Provisional Translation
The 2004 White Paper on Nuclear Safety
May 2005
Nuclear Safety Commission
The 2004 White Paper on Nuclear Safety (Contents)
Introduction Part 1 Safety Regulation for Nuclear Decommissioning and Clearance System Facility
The status of the on-going examination is described; it covers the regulation of nuclear facility decommissioning and the clearance level at which the decommissioned waste materials are not necessarily treated as radioactive materials. Chapter 1 Safety Regulation System on Nuclear Facility Decommissioning Chapter 2 Clearance System of Nuclear Facility
Part 2 Work in 2004
An explanation of the main Operations of the nuclear safety regulation of the Nuclear Safety Commission and the regulatory bodies in 2004 and Mihama Unit 3 Accident. Chapter 1 Activities of the Nuclear Safety Commission Chapter 2 Accidents and Malfunctions in 2004
Part 3
Government Activities for Ensuring Nuclear Safety
An introduction of various activities for the general preservation of nuclear safety in Japan. Chapter 1 Safety Regulation Systems for Nuclear Facilities Chapter 2 Disaster Preparedness of Nuclear Facilities Chapter 3 Progress in Nuclear Research Chapter 4 Environmental Radiation Surveys Chapter 5 International Cooperation on Nuclear Safety
Appendices
Various materials and data related to the Nuclear Safety Commission
The 2004 White Paper on Nuclear Safety
Introduction
A key term simply expressed on the present status of the nuclear safety assurance in Japan is
[Quality Control System]
Accidents and Malfunctions of Nuclear Facilities in 2004 There were 23 reports defined as accidents and malfunctions in 2004. Many of their causes were parts that were either damaged or out of order, defacement of piping, stress corrosion cracks etc. Human errors such as lack of continuous knowledge between workers at periodical inspection are also reported. The Secondary System Piping Rupture Accident of the Mihama Nuclear Power Plant Unit 3, Owned by Kansai Electric Power Company (August, 2004) Although the rupture could be protected by means of the appropriate management to be done along with the managing guideline set up independently by the owner, the fact that the rupture portion was not included in the inspection list and for a long time no one noticed, which forced the accident to occur. The defect of the owner's quality control system were exposed. Quality Control System of Rokkasho Reprocessing Facility in Japan Nuclear Fuel Ltd. The Nuclear and Industrial Safety Agency demanded to persist in their safety regulation activities, including quality control systems. It also stressed future security based on, among other factors, improper welding construction. of facilities and equipment in March, 2004. Radioisotopes Handling The radioisotopes that should have been managed within the controlled area were actually frequently left outside that area. The Ministry of Education, Culture, Sports, and Science notified the storage management of the radioisotopes to be implemented thoroughly in July, 2004. It is important to avoid a carelessness. The improvement of safety should be always the goal. and the quality control systems should function appropriately.
The Nuclear Safety Commission will promote the improvement of quality control systems for safety assurance in the future.
Part
1
Safety
Regulation
for
Nuclear
Facility
Decommissioning
Safety Regulation Decommissioning
and Clearance System
System on Nuclear Facility
Chapter 1
. Safety Regulation on Nuclear Facility Decommissioning
Present Status of Decommissioning in Japan
The JRR-1 that was the research reactor of the Japan Atomic Energy Research Institute achieved criticality for the first time in our country in August, 1957. The Japan Power Demonstration Reactor (JPDR) of the Japan Atomic Energy Research Institute performed nuclear power generation for the first time in October, 1963. The Tokai power plant of the Japan Atomic Power Company Ltd. a nuclear reactor for commerce began commercial operations in July, 1966. Thus, Japan’s history of nuclear power generation in our country stretches back almost 40 years. The JPDR ended operations in 1976; the dismantling and removal of buildings and equipment was done from 1986 to 1996. Radioactive wastes were buried, and the site of the JPDR was leveled.
Before dismantling
After dismantling
Example of dismantlement removal of the Japan Power Demonstration Reactor (JPDR) of the Japan Atomic Energy Research Institute
Presently, eight of the test research reactors besides the Tokai power plant of the Japan Atomic Power Company Ltd are being dismantled, and seven nuclear reactor facilities have completed decommissioning. Nine nuclear reactor facilities are now being dismantled.
Examination Concerning Decommissioning of Nuclear Facilities in the Nuclear Safety Commission
Regarding the decommissioning of nuclear facilities the Nuclear Safety Commission in 1985 published a document titled "Basic Idea of the Safety Assurance on the Dismantlement of Nuclear Reactor Facilities” on December 19, 1985 (and partially revised on August 6, 2001) that considered the increasing possibility of further reactor dismantling. The generation of radioactive waste from facilities, the change of the radiation level in facilities, and the change of the situation of necessary safety devices (among other factors) under the progressing dismantlement are covered. Moreover, it was shown to have to adopt an appropriate dismantlement removal engineering method and dismantlement removal procedure to attempt to decrease radiation exposure to the public and, especially, to radiation workers, and to evaluate the amount of the radiation exposure appropriately beforehand. The dismantlement of the Tokai power plant of the Japan Atomic Power Company progressed, and various concrete acts according to the dismantlement of the nuclear plant were carried out. However, the safety regulation at the present decommissioning stage of nuclear reactor facilities was applied on the basis of the system of law enacted in the past year, when the actual decommissioning situation was insufficiently assessed. Based on the above situation, the Nuclear Safety Commission carried out a “regulation investigation concerning the safety regulation system since after the operation termination of nuclear reactor facilities," and presented the investigation results in October, 2004. Although this regulation investigation was carried out for the nuclear reactor facilities, afterwards the Nuclear Safety Commission conducted an investigative discussion of fundamental thoughts on the safety regulation system since after the operation termination for all Japanese nuclear facilities, including not only nuclear reactor facilities but also nuclear fuel facilities. That is, the Nuclear Safety Commission examined the idea of ideal safety regulation, based on the experience of the decommissioning of the nuclear facilities. It also took into consideration the features of the nuclear facilities post-termination and the level of the potential risks, and issued a document titled, "An Ideal Safety Regulation System for Nuclear Facilities Post Termination” in February, 2005.
Current Status and Problem of Safety Regulation System at Decommissioning Stage
The current status and the problem of the safety regulation system at the decommissioning stage is as follows. 1. While the present safety regulation system is focused on the regulations necessary for construction and operation, the nuclear reactor facilities are not necessarily considered sufficient on legislation for dismantlement and decommissioning Post-termination. 2. Regulation content should be changed according to different safety activities, because the main safety activities post-termination differ from those while under operation. 3. It is necessary to examine safety regulations so that a necessary inspection and confirmation could be implemented at the appropriate time according to an important level of safety assurance. 4. In the regulation bodies, it is hoped to begin a review of the safety regulation system. 5. As for the nuclear fuel facilities, the features and operative forms of each facility are different. 6. Safety regulation on the dismantlement of large-scale facilities such as post irradiation examination facilities for nuclear fuel (among others) has not been institutionalized. 7. Unless nuclear fuel material. and radioactive waste can be shipped out even after dismantlement is finished, the decommissioning is not complete.
Feature of Nuclear Facilities in Decommissioning Stage
Nuclear facilities in the decommissioning stage on which the investigation discussion was done by the Special Committee on Radioactive Waste Disposal Safety and Decommissioning Safety in the Nuclear Safety Commission are fetured as follows.
(1).
Nuclear Reactor Facilities
1) The type, the nuclear power, and the operation form of the nuclear reactor are vared, and the level and range of both the activation of the equipment and the structure and the contamination by the radioactive differ greatly. 2) Aspect that should be examined on safety assurance upon dismantling are different in each nuclear reactor. 3) The amount of the radioactivity to which the nuclear reactor facilities are involved decreases greatly at each stage of dismantlement. 4) The decommissioned land may be cleared and reused for other purposes.
Tokai Nuclear Power Plant in Japan Atomic Power Company Ltd.
(2) Refinery Facilities and Fabrication Facilities 1) Radioactive waste contaminated by nuclear fuel material, along with nuclear fuel material itself (depleted uranium and scrap) may remain. 2) A facility may dismantled in bulk or in part. 3) During the dismantling, sign of remaining uranium and other contamination must be posted. 4) It is necessary to consider the confinement and inner exposure in plutonium handling facilities.
Nuclear Fuel fabrication Facility(fuel assemblies in Mitsubishi Nuclear Fuel Ltd.)
(3) Reprocessing Plant 1) It is possible to dismantle a facility in bulk and in batches. 2) It is necessary to consider the contamination of each facility by plutonium and fission products.
Reprocessing facility of Reprocessing Works in Japan Nuclear Fuel Ltd.
(4) Waste Facilities( underground waste and management) 1) Because facilities of underground waste contain only trace amounts of radioactivity, the consideration to safety assurance of exposure is small. 2) As for management facilities, the potential risk is the same level as the waste facilities of other nuclear facilities. Management facilities of vitrified waste contain trace amounts of radioactivity that remain after shipping it outside the site; the potential risk is low.
Storage pit of High Level Radioactive Waste Storage Management Center in Japan Nuclear Fuel Ltd.
(5) Use Facilities 1) The amount of the radioactive material handled varies, depending on the facility. 2) Potential risk to the use facilities where a large amount of spent fuels and plutonium are handled might be large in comparison to the processing facilities and the test and research reactors. 3) Consideration according to the features of each facility, including the level of contamination and the activation, is needed.
Nuclear fuel Use Facility (Hot Lab Facility of Japan Nuclear Fuel Development Ltd).
Consideration To Safety Regulation System on Decommissioning
In "Basic Idea of the Safety Assurance on the Dismantlement of Nuclear Reactor Facilities," which was documented by the Nuclear Safety Commission, the following five items have been identifiied as items that should be considered when the nuclear reactor facilities are dismantled. 1. Ideal function-stop measures of reactor To remove all nuclear fuels and neutron sources from the reactor core of the reactor. To ship the removed nuclear fuels outside facilities or to keep them in storage facilities. Ideal maintenance management of reactor facilities under dismantlement To prevent a third party from illegally approaching the reactor facilities being dismantled. To divide appropriately a controlled area so as to prevent workers from needless exposure. To isolate and enclose appropriately a system for leakage prevention of the remaining radioactive materials. 3. Ideal safety assurance in dismantlement work To evaluate amount of remaining radioactive materials and radioactive waste. To chose procedures and work methods for the dismantling paying special attention to decontamination and to shielding materials. To make the safety assurance plan available to the public. Ideal way of confirmation of dismantlement completion To remove all nuclear fuels. To carry out thoroughly the appropriate disposal of all radioactive waste materials. Reduction of exposure To make a plan of safety assurance on the basis of the fundamental principle ALARA, radiation dose limit shown by the International Committee on Radiation Protection (ICRP)
2.
4.
5.
. Examination of New Regulation System on Decommissioning
Examination of the Nuclear Safety Commission
The Nuclear Safety Commission has created the following ideas on the ideals of safety regulation of the nuclear facilities in the decommissioning stage. (February, 2005)
(1) Operation termination stage The system of the safety regulation applied while under operation need not be applied in principle. When the system is examined, it is necessary to construct the mechanism of the safety regulation for safety assurance corresponding to the level of potential risk. (2) Stage from beginning of dismantlement to end It is necessary for the safety regulation system during the dismantlement period to pay attention to safety assurance in the dismantlement work. It is also necessary that the regulation body appropriately participates. It is necessary for the regulation body participation to take measures on security corresponding to the level of potential risk on the basis of step by step based on the feature and the progress status of the dismantlement of facilities. (3) Stage from dismantlement completion to decommissioning It is necessary for the regulation body at the decommissioning to appropriately take part in safety assurance such as confirmation of the execution condition of the measures taken by the owner. Where two or more reactors exist in the same site, the decommissioning of each reactor should be done one by one.
Examination of the Regulation Body
Regarding the ideal way of regulating the decommissioning of reactor facilities, the fundamental idea of the safety assurance on the dismantlement of reactor facilities, "Aiming at Decommissioning of Commercial Nuclear Power Facilities " (Nuclear Energy Subcommittee, Advisory Committee for Natural Resources and Energy in January, 1997) and "Idea of Safety Assurance and Safety Regulation on the Decommissioning of Nuclear Reactor Facilities for Practical Power Generation" (Decommissioning Safety Subcommittee of Nuclear and Industrial Safety Subcommittee of Advisory Committee for Energy in August, 2001 ) have been examined so far.
The Nuclear and Industrial Safety Agency examined the transparency of the regulations and the ideal regulation system at the stage of the dismantlement and decommissioning under a major premise: necessary safety assurance based on the regulation experience until now on the dismantlement and the reactors and the document titled, “Ideal Way of the Decommissioning Regulation of the Nuclear Facilities" was published in December, 2004. Moreover, the Ministry of Education, Culture, Sports, Science and Technology examine the ideal way regulating at the stage of the dismantlement and decommissioning for the test and research reactors and nuclear fuel use facilities under a major premise of the safety assurance based on the safety regulation until now on the dismantlement and the decommissioning and the document titled “Ideal Way of the Safety Regulation on Test and Research Reactor Facilities," issued in January, 2005. An examination was carried out on the revision of a part of the Nuclear Reactor Regulation Law including the regulations concerning quitting of business and other issues. The main contents are - To obligate the consideration of decommissioning, and to obtain the authorization of the decommissioning plan beforehand when the owners are about to quit the business. - To receive the relevant minister's confirmation upon the completion of the decommissioning. - A phased regulation is enabled on the application of the regulation of facility regular inspection and the operation plans in the decommissioning stage considering whether or not there are the remaining nuclear fuel materials.
safety assurance in operation of reactor
function change of facility required on safety
safety ensure in decommissioning containment (radioactive material)
unnecessary function maintenance required to spent fuel storage facility, excluded part of waste processing system, etc. Risks such as radioactive material being released in to environment with fuel shipment from the facility are reduced.
stop, cool, contain
maintenance of facility function
change of important security activity
security activities mainly for operations
dismantlement work management, radiation management, waste management, nuclear fuel material management
time until spent fuel shipment
Figure. Difference of thought to safety assurance between in operation and in decommissioning of nuclear reactors.
continuation of owner and permission In decommissioning In operation
transfer, decontamination, waste, etc
dismantlement and other measures
operation termination approval application of plan decommissioning process and method of "dismantlement and other measures" process and disposal of radioactive waste
dismantlement of facility and decontamination with change of the facility
confirmation
criteria of permission
decommissioning completion confirmation application confirmation criteria
regulation based on decommissioning plan (compliance obligation of decommissioning plan)
facility regulation regulation for waste and transfer out of sate security regulation nuclear material physical protection regulation [point] 1. To apply a "decommissioning rule" to a decommissioning of the part of the reactor facility 2. Facility regulation and safety regulation in the decommissioning stage are concretely provided as a ministerial order to assume a reasonable regulation level corresponding to the decommissioning.
Figure. image of new decommissioning regulation
The government submitted an amendment bill to the 162nd regular session of the Diet on a part of Nuclear Reactor Regulation Law including regulations concerning the quitting of business and other issues, based on the report to clarify the participation of the state in the dismantlement and the decommissioning of the nuclear facilities and to enhance the decommissioning regulation.
. Future Issues
Issues that should be examined in addition in the future include the following. Because the decommissioning is carried out with a part of the facilities remaining in case a part of the nuclear reactor facilities is utilized as re-used for other purposes it is necessary to examine the standard (i.e., the site liberating standard) since no radiation protection is necessary when the decommissioning is completed. Furthermore, because a comparatively high active density waste could be disposed by the underground waste disposal by choosing the place "where the depth is considered to be much more affordable (for example about 50 to 100 meter from ground surface)” against underground usage. In general, however, it is necessary to examine concretely the safety regulations of such an underground disposal. In the mean value of each prefecture of the natural radiation during a year in Japan, a width of 0.4 milli-sieverts (400 micro-sieverts) is the maximum. It can be said that the value of 10 micro-sieverts/year is a very small value compared with this.
Chapter 2 Clearance System of Nuclear Facilities
. Clearance System
What is Clearance?
We have received radiation of about 2.4 milli-sieverts a year on a global average from the natural radiation that originates in naturally occurring radioactive materials (uranium, radon, potassium 40, etc.) in the earth, in the air, in the human body, in food, and in cosmic rays. Clearance: To remove from the framework of the regulation on radiation protection, since “it is not necessary to treat as a radioactive material" Clearance Level: Level at which a material not necessarily treated as a radioactive material is divided The global standard for materials exposed to radiation to not be to be treated as radioactive materials is an individual annual exposure of several ten micro-sieverts or fewer. Based on this, the Nuclear Safety Commission considers the reference dose as 0.01 milli-sieverts a year (ten micro-sieverts *) (1/100 or less of the amount of the annual exposure received from the natural world), and calculates the clearance level by converting the reference exposure into the density of the radionuclide. In the mean value of each prefecture of the natural radiation during year in our country, there is width of 0.4 milli-sieverts (400 micro sievert) in the maximum. It can be said that the value of ten micro-sieverts/year is a very small value compared with this.
Daily life and radiation
Natural radiation The clearance level (10 sieverts / year) is about 1/200 of the amounts of the dose received from the radiation of nature(2,400 micro-sieverts/ year).
Amount of radiation (millisievert)
Radiation of Brazil Gravari (annual, from the earth, and others)
Artificial radiation
Chest X-ray computer tomography inspection (CT scan) (once)
from space natural radiation per person (global average) from earth General public's dose limit (year; medical treatment is excluded) Gihu by the inhalation (mainly radon) Difference of domestic natural radiation (year) (maximum of difference of each prefecture mean value) X-ray mass examination of stomach (once) Kanagawa
from food
X-ray mass examination of chest (once) Tokyo - New York aircraft travel (round trip) (increase in cosmic rays by high attitude)
* 1 milli-sievert (mSv) =
Dose target value (year) around nuclear power plant (light-water reactor). (Results are less than 0.001 milli-sieverts, and it greatly falls below this target value.)
1000 micro-sieverts (µSv)
Dose target value (year) of clearance level derivation
adapted from “Atom 2003” (Agency for National Resources and Energy) (partially added)
Necessity of Clearance System
As the dismantlement of the reactor facilities progresses, materials exist that are not contaminated with radioactive matter, and that are not treated as radioactive materials contaminated with radioactive materials of extremely low level, adding to the radioactive waste materials to be controlled from the viewpoint of radiation protection. However, because at present no criteria exist for a meaningful distinction between radioactive waste materials and waste materials, even materials not be treated as a radioactive material are handled as radioactive waste materials. It is thought that such handling does not work well with the government’s promotion of the formation of a “recycling society.” Such promotions include waste-generation control, the re-use of products multiple uses of raw materials, and many others. Such handling is both inappropriate and inefficient from the viewpoint of the social costs involved. From such a viewpoint it is necessary to establish a system (a clearance system) that divides radioactive waste and materials that are not necessary to treat as radioactive materials.
. Examination of Clearance in Domestically and Overseas
Fundamental Concept of Clearance
The following three ideas have been crudely proposed in discussions both domestically and with international organizations, including the International Atomic Energy Agency (IAEA), centering on how to divide materials to be treated (or not treated) radioactive material.
(1) clearance: "Removal of the radioactive source from the framework of the regulatory control on radiation protection due to the small risk it poses to the health of people exposed to a certain radioactive source." (2) exemption: "Not be subject to the framework of the regulatory control on radiation protection due to the small risk it poses to the health of people exposed to a certain radioactive source." (Example: fluorescent paint) (3) exclusion: "Originally, regulatory control did not target minute radioactive sources such as the radioactive materials contained in soil, cosmic ray, and others that exist in the natural world, which cannot be controlled." (Even if they could be controlled, it
wouldn’t be effective to do so.)
Examination Situation of Clearance in the International Atomic Energy Agency
The IAEA general conference in September, 2000, resolved to settle the argument on the density of the radioactive material acceptable in a given commodity (especially food and wood) for the smooth international trade of that commodity in regions contaminated by a nuclear accident. The IAEA deliberated on derivation of the density of the radioactive material for setting up exemptions and clearance levels. The "Safety Guide RS-G-1.7: Application of the Concepts of Exclusion, Exemption and Clearance " (hereafter, the IAEA Guide) was arranged and published in August, 2004. Materials in the IAEA guide are solid materials in bulk, except foodstuffs and drinking water, and the activity concentration (exemption level) of each radionuclide, which is applicable for the exemption, is derived from the exclusion concept on the nuclide of a natural origin and the exemption concept on the nuclide of an artificial origin, respectively. And, it is assumed that this exemption level may be used as a clearance level to a similar material. In the IAEA guide, the dose criterion (the level assumed to be an exemption if it is below this dose) when the exemption level of the radionuclide of an artificial origin is decided is shown the order of 0.01 milli-sieverts (10 micro-sieverts)/year or less in effective dose to the individual with the radionuclide concerned. The activity concentration that may be used for exclusion, exemption, and clearance to radionuclide of natural origin is shown in Table 1. That of artificial origin about typical nuclides appears in Table 2.
Table 1. Values of activity concentration for radionuclides of natural origin to be applied for exclusion, exemption, and clearance Activity concentration (Becquerel/g) 10 1
Radionuclide potassium - 40 All other radionuclides existing naturally other than above
Table 2. Values of activity concentration for main radionuclides of artificial origin, in bulk Activity concentration (Becquerel/g) 100 1 0.1 0.1 1 1 Activity concentration (Becquerel/g) 0.1 0.1 0.1 0.1 0.1 1
Radionuclide H-3 C-14 Mn-54 Co-60 Sr-90 Tc-99
Radionuclide Sb-125 Cs-137 Eu-152 Pu-239 Am-241 Cm-244
Examination of Clearance in the Nuclear Safety Commission
(1) Current actions Up to now, the Nuclear Safety Commission has arranged the following reports. • "Clearance Level in the Main Nuclear Reactor Facilities" (1999) (object: nuclear commercial power reactor facilities (light water reactor) and gas reactors) • "Clearance Level in Heavy Water Reactors and Fast Reactors" (2001) (object: Test and research reactor and research and development stage reactor) • "Clearance Level in Nuclear Fuel Use Facilities” (irradiated fuels and materials handling facilities ) (2003) (object: nuclear fuel use facilities) Moreover, the "Ideal Clearance Level Verification in Nuclear Reactor Facilities" was arranged in 2001.
(2) Review of clearance level The Nuclear Safety Commission has asked the Special Committee on Radiation Waste Disposal Safety and Decommissioning Safety to extract the latest findings, which should be reflected in the three reports mentioned above, from the application concept of the exemption level and the
evaluation method shown in the IAEA guide on clearance level. The Committee then reviewed and reevaluated the clearance level of the reports, which were subsequently published by the Nuclear Safety Commission. The evaluation was conducted under the consideration of four items: skin exposure dose evaluation, review of dose conversion coefficient (adult), addition of direct oral intake pathway, and children between the ages of one and two. The result was arranged in December, 2004 as "Activity concentration for making decisions on radioactive material on whether or not is should be handled as radioactive, one of which is generated along with the dismantlement of nuclear reactor facilities and nuclear fuel use facilities." Comparing the calculation value of the clearance level reevaluated with the calculation value of the clearance level in the report, the large difference of the numerical values is to only nickel-59 and nickel- 63 of 1/10 less or 10 times more. We can conclude that there was no great divergent value about most nuclides, even though it is different from most nuclides.
Table 3. Minimum value of activity concentration of equivalent to 0.01 milli-sieverts (ten micro-sieverts)/year and calculation value at clearance level in each examination item (Becquerel/g) Calculation value reevaluated at clearance level 64 3.8 1.6 0.31 35 130 0.19 Calculation value at clearance level in the report until now 220 5.1 1.1 0.37 560 1900 0.20
Name of nuclide H-3 C-14 Mn-54 Co-60 Ni-59 Ni-63 Pu-239
(3) Setting of clearance level The exemption level of the IAEA guide targets general solid material. Because it is not limited to the waste generated by the dismantlement of the nuclear reactor facilities which is within the applicable range by this review the comparison of the calculation values reevaluated of the clearance level with the calculation value which had been used when the exemption level of the IAEA guide was derived, were done, though it should not be compared directly with this revaluation result.
In the IAEA guide, the standard of the amount of an individual dose when the exemption level is derived should be about 0.01 milli-sieverts (ten micro-sieverts)/year or same level (one figure less concretely). Moreover, because the exemption level is a very low value in comparison with the radiation level of the natural world that we usually receive, it is admitted that the actual exemption level to be implemented is about 10 times less than the derived exemption level by the judgment of each country’s regulatory body. Based on above, the difference between the reevaluated calculation value of the clearance level shown by the Nuclear Safety Commission and the calculation value of the IAEA guide is approximately the majority of radionuclides within one figure; it is almost equal substantially to the ideas of the IAEA guide. Therefore, taking into account that the reevaluated calculation value of the clearance level and the calculation value of the IAEA guide are almost equal, it is appropriate to adopt the clearance level that the Nuclear Safety Commission reevaluated; it also decided on a large amount of materials, generated along with the dismantlement of the nuclear facilities from the viewpoint of an international adjustment, or to adopt the exemption level of the IAEA guide that is, a general exemption level as the clearance levels of concrete and metals that are generated as Japan’s nuclear reactor facilities are dismanled.
Low-level nuclear waste (about 1 percent)* The one that it is not necessary to treat as radioactive waste (about 3 percent)*
Clearance Level
(10 micro-sieverts)/year
The exhaust tower
Concrete wall Containment
Object: Metal and concrete, etc.
The pressurizer The pressure vessel The steam generator The main steam Control rod (steam) The turbine The dynamo
The filter for the emergency
The condenser (Water) Fuel
(Marine water)
Waste that is not radioactive waste (about 96 percent)* (There is clearly no contamination by adhesion, infiltration etc., of radioactive material from the use history)
It is possible to recycle as industrial waste.
Water (moderator coolant)
Example of pressurized water reactor (PWR)
* Quotation from Waste Sub committee in Nuclear and Industrial Safety of Advisory Committee for Energy "Maintenance of clearance system in nuclear installation".
adapted from “ATOMIKA” (partially added)
. Examination for Institutionalization of Clearance
With regard to the examination of the Nuclear Safety Commission, the Nuclear and Industrial Safety Agency carried out an examination in the Waste Safety Subcommittee on the fundamental matters of necessary technological requirements for clearance verification, assuming a concrete safety regulation for the verification by the regulatory body on the basis of sharing a role between the state and the owners concerning the verification system focusing on the clearance level verification method that is highly reliable and reasonably applicable. A report entitled "Maintenance of the Clearance System in Nuclear Installation" was then published in September, 2004. Based on the situation of test and research reactor facilities, reactor owner’s development toward implementation of radioactive waste disposal, and the status of the examination of clearance, the Ministry of Education, Culture, Sports, Science and Technology also carried out an examination on the clearance system in the safety regulation examination meeting for research reactors, in consideration of each role of among regulation bodies and reactor owners, to introduce the clearance system of test and research reactors. A report titled, "Ideal Safety Restrictions--Nuclear Reactor Facilities for the Test Research" was published in January, 2005.
government approval of measurement and judgment method *1 government confirmation of measurement and judgment result*2 -pre-examination -verification object selection -establishment of measurement judgment method ( reuse and reproduction use ) ( appropriate disposal ) *3 Measurement and judgment of clearance level verification object dismantlement or modification
small components, concrete structures, etc. dismantlement or withdrawal
measurement judgment large component
measurement judgment building, building all-in-one design equipment
dismantlement or modification
private standard establishment of criterion of measurement and judgment method
record
The use of the Japan Nuclear Energy Safety Organization as an implementation body.
* 1. Government approval of measurement and judgment method (review content upon approval) Establishment method of radioactive nuclide selection for evaluation object and composition ratio, setting and measuring method of measurement condition corresponding to characteristic of object, evaluation method of measurement result, method of temporary storage of object completed measurement and judgment, confirmation of record, creating quality assurance, and others. *2. government confirmation of measurement and judgment result The record concerning the measurement and the judgment done based on the method of obtaining approval is confirmed (using extraction measurements, if necessary). Moreover, the state can conduct at an appropriate opportunity the confirmation of implementation status of quality assurance activity concerning a series of measurements and judgments for the objects selected by reevaluation. *3. It is requested that owners should hold and record the first shipping location upon disposal and reproduction use of clearance objects until the system is established.
Custody, management and shipment
measurement judgment custody and management
The government, based on the arranged report, submitted a part of the Nuclear Reactor Regulation Law amendment bill to the 162nd regular session of the Diet, proposing that the system which enables the handling of extremely low radiation levels among materials caused from the nuclear facility as materials that are not" contaminated by nuclear fuel material," and thus liberating it from the regulation of Nuclear Reactor Regulation Law, was introduced.
. Future Issues
The following issues are shown as the ones that should be examined furthermore in the future. It will be necessary to examine the clearance system, including waste generated from smelting facilities, fabrication facilities, reprocessing facilities, and radioisotope use facilities, which have not been heretofore examined. Moreover, it is thought that an examination of the clearance level of radioisotopes should be necessarily done consistent with the exemption level above, mentioned on the basis of the movement; that is, the IAEA is planning to examine to take the IAEA guide to international fundamental safety standards. It is also important to examine the clearance of the waste contaminated with the uranium generated from the smelting facilities, fabrication facilities, etc., referring to the exemption level of the IAEA guide and to the regulatory method of NORM*1 and TENORM*2 in the IAEA and each country’s exemption level. In the future, the clearance level and the exemption level for waste that has not yet been examined shall be examined from view point of a safe and reasonable processing disposal and effective use for the resource for the waste generated by the use of nuclear power or the radioisotope.
1 NORM Naturally Occurring Radioactive Material as technological use or its by-product
natural radioactive material
2 TENORM Technically Enhanced NORM natural radioactive material of which density is increased
Part 2 Work in 2004
Chapter 1 Activity of the Nuclear Safety Commission
The new "The Basic Policies of the Nuclear Safety Commission,” revised in 2004, is introduced. In the new basic policies, both the items to be solved within the next three years or so and the issues to be steadily discussed form a long- term viewpoint are shown below as three pillars. (1) Improvement and reinforcement of the quality in the present activities of assurance (2) Further enhancement of the nuclear safety regulatory system in foreseeing the future (3) Establishment of firm basis of infrastructure for nuclear safety assurance In reviewing and executing these matters, it will be necessary to carefully watch and positively cope with world-wide movements more than ever, because the matters regarding nuclear safety assurance have been widely recognized to be globally important issues.
Moreover, the reports issued by the Nuclear Safety Commission in 2004 are presented. The main reports are as follows: - Basic concepts concerning safety regulation of near-surface disposal for radioactive solid waste generated from radioisotope use facilities - Examination guide concerning the technical ability of nuclear power owners - Common important matters in the safety regulation of radioactive waste disposal - Important nuclear safety research plan - Interim report by the Subcommittee on the secondary system piping accident at Mihama power plant Unit 3. The document of "Examination Guide Concerning the Technical Ability of Nuclear Power Owners" is indicating the fundamental requirements upon the examination concerning the adaptability of having a technical ability to suffice for the appropriate accomplishment of the owners who intend to run the business of fabrication, storage, reprocessing, and decommissioning, and to set up a nuclear reactor by the Nuclear Reactor Regulation Law in order for the disaster not to be caused by the use of the nuclear fuel material and the nuclear reactor.
- Basic requirements Construction of organization with clarified roles Holding on to engineers Sufficient experience Quality assurance activity Education and training Selection and arrangement of qualified persons. In addition, the following are mentioned: the activity status of each Special Committee, the implemented regulation review, the safety culture opinion exchange meeting, and the information disclosure task force et al in 2004.
Chapter 2 Accidents and Malfunctions in 2004
The outline and the response of the regulatory bodies to the secondary system piping rupture accident at the Mihama power plant Unit 3 of the Kansai Electric Power Company happened in 2004 are introduced.
- Outline of accident During the operation at the rated thermal output of the Mihama Unit 3 (Mihama-cho, Mikata-gun, Fukui Prefecture, the output of 826,000kW and PWR) of the Kansai Electric Power Company, the warning signal of "fire alarm" in the central control room was dispatched at 15:22 in August 9, 2004 and the reactor stopped automatically at 15:28. A rupture was confirmed in the A system condenser piping, which is the water supply line to air ejector from the 4th low pressure water supply heater in the vicinity of the ceiling of the air ejector of the 2nd floor, as a result of the check in the turbine building. As a result of this accident, five workers of the enterprise that did the preparatory work of the periodic inspection in the turbine building died by the steam and the high-temperature water that flowed out upon the rupture occurred. Six people were also injured, though the reactor stopped safely and there was no trace of radiation.
Schematic system figure
Reactor containment vessel
Pressurizer Steam Control rod Water High-pressure turbine
Water Condenser
Steam
Low-pressure turbine
[condenser piping] outer diameter: about 560 mm Thickness: about 10 mm Maximum inner pressure: about 1.27 MPa Maximum temperature: about 195 Material: Carbon steel Flow rate: about 1,700 t/hour
Electric generator
Circulating water pomp
Sea water
Condenser pump
Sea water
Steam generator High pressure heater
Ejector
Water Outlet Condensate demineralizer No.1 Main water supply pump No.2 No.3 No.4 Ground steam condenser
Fuel
Water
Reactor vessel
Coolant pump
A-condenser piping ruptured portion
Low pressure water supply heater
- Response of the Nuclear Safety Commission The Nuclear Safety Commission held a special meeting on the day after the accident on August 9, 2004, and decided on the policies to be take regarding the accident. It then carried out an investigation at the site on the 11th of August, and set up the Subcommittee on the Secondary System Piping Accident at Mihama Unit 3 on the 13th. It is now examining this accident further. As for "Interim report" of the accident investigation by the Nuclear and Industrial Safety Agency (NISA) issued on September 27, 2004, the Subcommittee interim report of October 20 in the same year and the Nuclear Safety Commission's decision made upon receiving it the next day (the 21st) pointed out a necessary discussion point for the examination of the cause investigation and a recurrence prevention plan on the basis that the fundamental directionality is appropriate in the future. The NISA made the final report on March 30, 2005, and the Nuclear Safety Commission received the explanation of the report from the NISA in Subcommittee on April 5. Taking this into account, the investigation discussion on the future action to be done by the Nuclear Safety Commission to the evaluation of the validity of the final report provided by the NISA and the regulation investigation is progressing (as of April 5).
The number of accidents and malfunctions and their outline in 2004 at nuclear power reactors, test and research reactors and other nuclear facilities were 23, and the evaluation by this International Nuclear Event Scale (INES) was 0 for all of them.
Nuclear power reactors Research reactors for basic study (Number of cases) 45 40 35 30 25 20 15 10 5 0 7 8 9 10 11 12 30 23 2 1 2 0 25 18 3 1 4 3 30 28 0 6 5 7 2
Research reactors for electric power Other nuclear facilities
0 2 1 14
3 2 14
1 2 3 1 10 15 16 (year) 20
13
14
Trends in the number or accidents and malfunctions at nuclear facilities reported to the Nuclear Safety Commission over the past 10 years.
Part 3 Government Activities for Ensuring Nuclear Safet
Chapter 1 Safety Regulation Systems for Nuclear Facilities
This chapter presents the safety regulation system in Japan for nuclear power reactor facilities, research reactor facilities of basic study, nuclear fuel facilities, the disposal and handling of radioactive wastes, transport of nuclear fuel materials, and radioactive isotopes.
Operator Adminisitrative agency Nuclear Safety Commission
Planning site selection
First public hearing (Main sponsorship by Ministry of Economy, Trade and Industry)
Planning stage
Application for nuclear reactor installation
Ministry of Economy, Trade and Industry evaluation Consensus of the Minister of Education, Culture, Sports, Science and Technology
Inquiry Response
Nuclear Safety Commission evaluation
Second public hearing (Main sponsorship by the Nuclear Safety Commission)
Approval of the Ministry of Economy, Trade and Industry Construction stage Application for construction plan approval Construction Ministry of Economy, Trade and Industry evaluation Construction plan approval
Pre-operation inspection Welding safety management evaluation Fuel INspection Safty regulation verification
Operation stage
Start of operation
Periodic inspection On-set inspection Safety review Periodic safety management evaluation Reports on operation
Regulatory review
Dismantling stage Decommissioning stage
Notice of dismantling Administrative order Notice of decommissioning Administrative order Reactor disposal
Flow from design stage to decommissioning for a nuclear power reactor facility.
Chapter 2 Disaster Measures at Nuclear Facilities
This chapter introduces the Special Measures of the Nuclear Disaster Act, established for the purpose of protecting the lives, assets, and health of citizens from the effects of a nuclear disaster. This act explains the responsibilities of nuclear power companies, the strengthening of the nation's emergency response system, and the role of the Nuclear Safety Commission under the Special Measures of the Nuclear Disaster Act. It also insures organic coordination between the central
government and local government bodies, and ensures initial prompt action after an incident occurs.
Tokyo
Report information regarding situations out of order Occurrence of a nuclear emergency
The Government Nuclear Disaster Management Headquarters Chief: Prime Minister Request for advice Technical advice The Government local Disaster Management Headquarters Technical advice Commission of the NSC Emergency policy research committee members Towns Municipal Disaster Management Headquarters
Off-site area Remote center Remote center
Prefecture Government local Disaster Management Headquarters Joint Council for the Management of Nuclear Disasters Prefecture Government Management Headquarters
Nuclear Safety Commission
Commission of the NSC Emergency policy research committee members Dispatch participation
Nuclear disaster management specialist
Instruction Information supplement etc.
Police, Fireman, Selfdefense forces etc. Nuclear power companies Prevent disaster from spreading
Instructions regarding evacuation, taking shelter indoors etc. Municipal government
Designated public organizations
Citizens
Emergency medical organizations for people exposed to radiation
Support for evacuation etc. Announce radiation level to public Relive victims Measure radiation exposure Removal of radioactive substances Emergency medical care for people exposed to radiation
Site of accident
Response system under the Special Measures of Nuclear Disaster Act
Moreover, the nuclear disaster training executed and the "Law Concerning the Measures to Protect the People During an Arms Attack" enforced in 2004, are referred.
Prior training for nuclear disaster prevention training in 2004 (Niigata Prefecture)
Chapter 3
Progress in Nuclear Safety Research
The latest scientific knowledge is continually reflected in the safety evaluation guidelines and safety reviews. An introduction to nuclear energy safety research contributes to the creation and maintenance of a high-level safety regulation system. Moreover, the "Prioritized Plan for Nuclear Safety Research" newly decided in July, 2004, was introduced. The Plan proposes safety research (prioritized safety research), that should be emphatically executed for about five years from fiscal 2005, and containing the following 12 items in seven fields.
. Regulation system field Utilization of risk information, analytical evaluation technologies of accident and malfunction factors . Light water reactor field Safety evaluation technology, material degradation and high-aging measures technology, earthquake-proof safety technology . Nuclear fuel cycle facility field Safety evaluation technology . Radioactive waste and decommissioning field Disposal of high level radioactive waste, Process and disposal of high βγ waste, TRU waste, uranium waste, and other wastes, decommissioning technology . Advanced reactor field Safety evaluation technology of fast breeder reactor . Radiation effect field Radiation risk and effect evaluation technology . Nuclear disaster prevention field Nuclear disaster prevention technology
Moreover, the importance of the fundamental and basic safety research as a technological base that supports such a prioritized safety research is pointed out.
Chapter 4 Environmental Radiation Surveys
This chapter explains the surveys conducted by the government, including the radioactivity surveys in the areas around nuclear facilities, handling of radioactive fallout, environmental surveys on the issues of misuse of weapons containing depleted uranium, and radioactivity surveys for bays, coastal areas, and the surrounding areas of the ports for nuclear-powered warships.
Chapter 5 International Cooperation on Nuclear Safety
This chapter introduces the current situation of nuclear safety regulation systems in various foreign countries, as well as international activities to ensure nuclear safety.
Appendices
Includes information on the organizational chart of the Nuclear Safety Commission (NSC), the main decisions of the NSC in 2004, safety evaluation guidelines established by the NSC, results of public hearings, and dose equivalent distributions for employees dealing with radiation at nuclear facilities, sites for nuclear facilities, and the operation and management status of nuclear facilities in Japan.