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					          50th Annual Meeting of the Institute of Nuclear Materials Management (INMM)

                            Tucson, Arizona, USA, 12-16 July 2009


Hidekazu Chayama and Eckhard Haas, International Atomic Energy Agency; Michael
Zentner, Pacific Northwest National Laboratory, USA; Jeremy Whitlock, Atomic Energy of
Canada Limited; Hong-Lae Chang, Won Il Ko, and Eun Ha Kwon, Korea Atomic Energy
Research Institute; Keyuan Zhou, China Institute of Atomic Energy

The international Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO) has
developed an assessment methodology, which covers holistically all facilities of a nuclear
energy system during their life time, and all associated institutional measures. The results in
several areas, including proliferation resistance, were published in October 2007. Currently
three activities are ongoing for improvement of the methodology in proliferation resistance.
The first one is a review of the results of national assessment studies using the INPRO
methodology. Six assessment studies have been performed by individual countries plus one
assessment study with international participation of eight countries. The workshop for
reviewing feedback and proposals from these national assessment studies was organized in
Vienna in February 2009. The second activity is an INPRO Collaborative Project called
PRADA (Proliferation Resistance: Acquisition/Diversion Pathway Analysis), focusing on the
methodology for evaluating INPRO User Requirement 4 regarding multiplicity and
robustness of barriers against proliferation covering each acquisition path. PRADA intends to
develop appropriate methods for the identification and analysis of high-level pathways for the
acquisition of fissile material for a nuclear weapons program, and make recommendations for
evaluating multiplicity and robustness of barriers along each pathway against proliferation.
PRADA is based on a case study of the DUPIC fuel cycle (Figure 1) conducted by the
Republic of Korea. Four consultancy meetings were held in 2007-2009. The third activity is
the continuous efforts together with the Generation IV International Forum (GIF) working
group on proliferation resistance and physical protection in order to address compatibility and
use of the both GIF and INPRO methodologies in this area. The above-mentioned activities
are all underway and contents publically available documentation is currently limited.
However, future direction of the INPRO methodology is of current interest of stakeholders
including technology holders and designers. Current statuses in these activities are reported.

In expectation of a nuclear “renaissance” and to help ensure a reduction of associated
proliferation risks, over the last few years the international community has conducted
substantial work on the proliferation resistance of future nuclear energy fuel cycles and
related facilities.

INPRO was launched in 2000. It’s purpose is to help ensure that nuclear energy is available
in the 21st century in a sustainable manner, and it seeks to bring together all interested

Member States, both technology holders and technology users to jointly consider , actions to
achieve desired innovations.

INPRO has developed a assessment methodology that can be used to evaluate whether
innovative nuclear energy systems (INS) are compatible with the objective of helping to
ensure that nuclear energy is available to contribute to fulfilling the energy needs in the 21st
century in a sustainable manner [1].

Proliferation resistance is one of the specific issues to be addressed, being relevant to the
development and deployment of INS sustainable energy supply. The INPRO assessment
methodology was published as IAEA-TECDOC 1575 [1].

INPRO has established a hierarchy of basic principles, user requirements and criteria that
must be fulfilled by an innovative nuclear energy system to meet the overall target of
sustainable energy supply. The highest level in the INPRO structure are Basic Principles
(BP), which are statements of general goals that are to be achieved in an INS and that provide
broad guidance for the development of an INS (or a design feature thereof). The second level
in the INPRO hierarchy are User Requirements (UR). URs are the conditions that should be
met to achieve users’ acceptance of a given INS.

Criteria (CR) are required to enable the INPRO assessor to determine whether and how well
a given user requirement is being met by a given INS. An INPRO criterion consists of one or
more Indicators (IN) and associated Acceptance Limits (AL). The AL of an INPRO criterion
is a target, either qualitative or quantitative, against which the value of an indicator can be
compared by the INPRO assessor leading to a judgement of acceptability (pass/fail, good/bad,
better/poor.). In correspondence to the two types of indicators there are also two types of
acceptance limits, numerical (for quantitative targets) and logical (for qualitative targets).
Typically, a logical AL is a positive (yes) or negative (no) answer to a question raised by the
indicator. Some indicators utilize Evaluation Parameters (EP). These parameters were
introduced to assist the INPRO assessor in determining whether the acceptance limit for an
indicator has been met [1].

The INPRO proliferation resistance (PR) methodology defined one BP: “Proliferation
resistance intrinsic features and extrinsic measures shall be implemented throughout the full
life cycle for INS to help ensure that INSs will continue to be an unattractive means to
acquire fissile material for a nuclear weapons program. Both intrinsic features and extrinsic
measures are essential, and neither shall be considered sufficient by itself.” To fulfil the
basic principle INPRO PR methodology presents five user requirements: 1) the State to
establish a sufficient legal framework, e.g., NPT, comprehensive safeguard agreement,
regulatory body etc; 2) the designer to keep the attractiveness of nuclear material low; 3)
make diversion of nuclear material difficult and detectable; 4) incorporate multiple barriers;
and 5) optimize costs of proliferation resistance measures, including safeguards. The set of
requirements in INPRO PR methodology is shown in Table 1.

In essence, INPRO PR methodology can be summarised as an approach to ensure that
safeguards experts confirm that nuclear facilities or system evaluated can be safeguarded
effectively and efficiently and that costs for implementing international safeguards are
affordable or minimized.

                                                           Table 1: INPRO PR methodology

      Basic Principle                          User Requirements                                                 Criteria                                      Indicators

BP Proliferation resistance         UR 1 States' commitments:                                      CR 1.1 Legal framework                         IN 1.1 States’ commitments, obligations and
features and measures shall be      States' commitments, obligations and policies regarding        CR 1.2 Institutional structural arrangements   policies established?
implemented throughout the full     non-proliferation and its implementation should be                                                            IN 1.2 Institutional structural arrangements in
life cycle for innovative nuclear   adequate to fulfil international standards in the non-                                                        support of PR have been considered
energy systems to help ensure       proliferation regime.                                                                                         accordingly?
that INSs will continue to be an
unattractive means to acquire
fissile material for a nuclear
                                    UR 2 Attractiveness of NM and technology:                      CR 2.1 Attractiveness of NM quality            IN 2.1 Nuclear Material quality
weapons programme. Both
                                    The attractiveness of nuclear material and nuclear             CR 2.2 Attractiveness of NM quantity           IN 2.2 Nuclear Material quantity
intrinsic features and extrinsic
                                    technology in an INS for a nuclear weapons programme           CR 2.3 Attractiveness of NM form               IN 2.3 Nuclear Material classification
measures are essential, and
                                    should be low.                                                 CR 2.4 Attractiveness of nuclear technology    IN 2.4 Nuclear technology
neither shall be considered
sufficient by itself.

                                    UR 3 Difficulty and detectability of diversion:                CR 3.1 Quality of measurement system           IN 3.1 Accountability
                                    The diversion of nuclear material should be reasonably         CR 3.2 C/S measures and monitoring             IN 3.2 Amenability
                                    difficult and detectable.                                      CR 3.3 Detectability of NM                     IN 3.3 Detectability of NM
                                                                                                   CR 3.4 Facility process                        IN 3.4 Difficulty to modify the process
                                                                                                   CR 3.5 Facility design                         IN 3.5 Difficulty to modify the facility design
                                                                                                   CR 3.6 Facility misuse                         IN 3.6 Detectability of misuse of technology or

                                    UR 4 Multiple barriers:                                        CR 4.1: Effectiveness of features and          IN 4.1 The extent by which the INS is covered
                                    Innovative nuclear energy systems should incorporate           measures                                       by multiple intrinsic features and extrinsic
                                    multiple proliferation resistance features and measures.       CR 4.2: Robustness of barriers                 measures
                                                                                                                                                  IN 4.2 Robustness of barriers covering an
                                                                                                                                                  acquisition path.

                                    UR 5 Optimization of design:                                   CR 5.1 Inclusion of PR in INS design           IN 5.1 PR has been taken into account as early
                                    The combination of intrinsic features and extrinsic            CR 5.2 Cost of PR features and measures        as possible in the design and development of
                                    measures, compatible with other design considerations,         CR 5.3 Verification approach                   the INS.
                                    should be optimized in the design/engineering phase to                                                        IN 5.2 Cost of incorporating into an INS those
                                    provide cost-efficient proliferation resistance.                                                              intrinsic features and extrinsic measures, which
                                                                                                                                                  are required to provide or improve proliferation
                                                                                                                                                  IN 5.3 Verification approach with a level of
                                                                                                                                                  extrinsic measures agreed between State and
                                                                                                                                                  verification authority?

The INPRO methodology has been applied by several INPRO member States (Argentina,
Armenia, Brazil, India, Korea, and Ukraine and the so-called “Joint Study” members
(Canada, China, France, India, Japan, Korea, Russia, and Ukraine)). The results of the
assessment study were reported and discussed at the Technical Cooperation (TC) Workshop
on Lessons learned from INPRO assessment studies, held from 16 to 20 in February 2009.

Member States’ recommendations based on their study were primarily related to the
following two points; 1) clarification for treatment of early design stages and 2) a need for
internationally accepted standards for evaluation parameters (EP) (or reconsideration thereof).
During the TC workshop it was emphasized that even if an INS is analyzed as “weak” or
“very weak” for some of the EP’s proposed in the analysis methodology, it does not imply
that the INS does not meet the assessment methodology AL’s. It was also stressed that weak
intrinsic proliferation resistance levels found by the analysis may require more stringent
safeguards. Moreover, an identified gap between UR or AL and current status of an INS may
also identify further R&D requirements for technology developers. Proliferation resistance
will be enhanced if it is taken into account as early as possible in the design and development
of a nuclear energy system. It will be most effective if an optimal combination of intrinsic

features and extrinsic measures, compatible with other design considerations, e.g. operation,
safety and security, is achieved in a nuclear energy system.

Through the workshop, a common understanding of the INPRO PR methodology was
achieved among the participating States. Results of the national assessment study will soon
be published. Based on the feedback from the workshop it was proposed to develop a nuclear
energy system assessment (NESA) support package. This issue will be addressed in the next
workshop to be held in July 2009 at the IAEA Headquarters.

The INPRO PR methodology needs to include an approach for evaluating User Requirement
(UR) 4 addressing the multiplicity and robustness of barriers against proliferation. This will
require a suitable acquisition/diversion pathway analysis.

In 2007, the project PRADA (Proliferation Resistance: Acquisition/Diversion Pathway
Analysis) was initiated as one of the INPRO Collaborative Projects by the following IAEA
Member States: Canada, China, the Republic of Korea, the USA and the European

The objectives of PRADA are to develop appropriate methods for the identification and
analysis of pathways for the acquisition of weapons-usable nuclear material, and make
recommendations for evaluating multiplicity and robustness of barriers against proliferation.
PRADA is based on a case study on the DUPIC fuel cycle (figure 1) conducted by the
Republic of Korea, which proposed the project.


           Spent PWR Fuel                                          Natural Uranium

           On-site Storage                                             CANDU

                                       DUPIC Fuel Fab
                                                               Spent CANDU/DUPIC Fuel
            AFR Storage

                                                                    On-site Storage
                                       PWR once-through
                                       CANDU once-through
          Permanent Disposal
                                                                  Permanent Disposal

                No                                                      Less

                             Figure 1: Concept of the DUPIC fuel cycle

PRADA consists of three stages:
– Stage 1: Selection of prospective pathways;
– Stage 2: Pathway Analysis and
– Stage 3: Assessment of multiplicity and robustness.

During Stage 1 [2], the threat analysis/definition (host State’s capabilities, institutional
arrangements and reasonable acquisition strategies) was described. Eight targets and 15
pathways were identified (Table 2). A systematic approach to pathway analysis was
developed (see Table 3). This approach will be used as the basic guideline for performing the
PRADA analysis. First a qualitative pathway analysis will be done and then if necessary a
quantitative proliferation resistance analysis may be performed based on the results of the
high-level qualitative pathway analysis. Quantitative pathway analysis may be useful for
evaluating robustness of barriers.

                      Table 2: Identified targets and possible diversion points
       Diversion targets                                 Possible diversion points
                                     1. During transport of spent PWR fuel assemblies from onsite storage
 Spent PWR fuel assemblies
                                        at PWR reactor to the DUPIC fuel fabrication facility
 Spent PWR fuel rod cuts             2. DUPIC fuel fabrication facility (after shearing step)
 PWR spent fuel pellets or fuel
                                     3. DUPIC fuel fabrication facility (feed line after decladding)
 material stuck on inside of hulls
 DUPIC fuel powder                   4. DUPIC fuel fabrication facility (before pelletizing step)
 Sintered DUPIC fuel pellets         5. DUPIC fuel fabrication facility (before welding stage)
 Sintered DUPIC fuel elements        6. DUPIC fuel fabrication facility (before welding stage)
                                     7. DUPIC fuel fabrication facility (product line in maintenance cell)
 Fresh DUPIC fuel bundles            8. Transport from DUPIC facility to CANDU power plant
                                     9. Fresh DUPIC fuel storage racks in the fuel storage bay
                                     10. Failed DUPIC fuel bundles from the reception bay of the plant
                                     11. Spent DUPIC fuel storage racks of the CANDU power plant
                                     12. Transport from CANDU plant to the Interim Dry Storage
 Spent DUPIC fuel bundles
                                     13. Interim Dry Storage
                                     14. Transport from Interim Storage to Permanent Disposal Repository
                                     15. Permanent Disposal Repository

Under Stage 2, qualitative pathway analysis has proceeded [3]. In this stage, sufficient design
and process information for the DUPIC fuel cycle system were collected and analyzed in
order to perform a detailed analysis of selected diversion pathways. Based on this
information an event sequence diagram (ESD) was developed for the scenario of covertly
diverting fresh DUPIC fuel from the storage bay of the DUPIC fuel cycle system. A draft
system notebook documenting the analysis has also been developed for this event sequence
diagram. It includes information such as system descriptions, identification of potential
safeguards systems to be installed in the DUPIC fuel cycle system, and concealment
strategies for the development of success trees for the selected diversion pathways.

                                    Table 3 Evaluation “Checklist”

                                      Activity                                              Complete
1   Identify State specific conditions, capabilities, institutional arrangements in place
    and reasonable acquisition strategies
2   Identify Innovative Nuclear Energy System (INS)
        • Establish Boundary conditions of INS considered/evaluated/assessed
             including operational state

3   Identify specific INS elements
4   Identify and categorize proliferation targets (Materials, equipment and processes,
    equipment and technology)
        • Define any needed clandestine facilities
5   Analyze INS elements to identify plausible acquisition/diversion pathways
        • Decomposition of the INS into sub-elements
        • Operational states of the system required for acquisition of the targets –
             Normal operational state
        • Identify different process steps in each sub-element – storage phase
6   Qualitative acquisition/diversion pathway analysis
        • Identify and describe acquisition strategies/coarse pathways including
             concealment strategies for each target
        • Specify possible means of acquisition of the targets including diversion
             points – transport containers
        • Identification of proliferation resistance intrinsic features and extrinsic
        • Check whether all identified pathways are covered by safeguards measures
        • Perform qualitative pathway analysis
        • Examine multiplicity and robustness of barriers
        • Select subset of pathways for quantitative analysis
7   Detailed quantitative acquisition/diversion pathway analysis
        • Identify proliferation resistance intrinsic features and extrinsic measures
        • Examine multiplicity and evaluate robustness of barriers
8   Go to step 4 as needed

The Evaluation “Checklist”, to help structure the analysis approach, is to be further
developed. It should include elements listed in Table 3.

The final report is expected to be drafted by the end of 2010.
The two most widely accepted methodologies for assessing the proliferation resistance of nuclear
energy systems have been developed by two international nuclear energy development programs,

INPRO and GIF. These programs have taken different but related approaches to evaluating
proliferation resistance. The necessity of efforts “harmonization” or “compatibility” of these two
approaches has been recognized among developers and potential users of the methodologies.

In this context, experts from INPRO and GIF met in at the IAEA in Vienna in May 2008 and
discussed similarities, differences and compatibilities of the two methodologies. The
participants recognized that the methods can productively be used in conjunction with each
other. For example, the GIF pathway approach is useful for evaluating INPRO User
Requirement 4 concerning multiplicity and robustness of barriers. Figures 2, 3, and 4 from
Pomeroy, G, et al. [4] display the interaction of the two approaches and the relationship
between the GIF Measures and INPRO User Requirements.

The participants agreed that continued interaction and exchange of information is important.
The results of the meeting and a discussion summary were reported at the Institute of Nuclear
Material Management (INMM) Annual Meeting last year [4].

Efforts to harmonize these approaches will continue through activities such as PRADA. The
stated purpose of PRADA is to further develop a documented approach for performing
proliferation resistance assessments using the INPRO methodology and where appropriate
the GIF methodology. As this paper demonstrates, procedures using the INPRO methodology
and appropriate aspects of the GIF methodology, can provide a basis for future analysis.
Based on current progress in this area of PR evaluation methodology including these efforts
between INPRO and GIF, a workshop on proliferation resistance assessment methodologies
is tentatively being planned for fall 2009.

Figure 2: Proliferation resistance assessments, GIF–INPRO comparison

                                                               State Requirements                                                  Annex 2
                                                              System Requirements

                                                                System Design

                                       Technology users                            Technology holders
                                        (States, utilities)     Who wants              (designers)
                                                                to know?

                   INPRO PR APPROACH                                                                  GIF PRPP APPROACH
                                                          UR4 (Multiplicity of Barriers)
           1. Basic principle                                                              1. Technology goals
           2. User requirements: (UR1 – 5)                                                 2. Measures
           3. Indicators                                                                   3. Metrics
                                                           Acquisition Pathway Analysis
           4 Assessment: evaluation parameters                                             4. Evaluation: challenge   response   outcomes
                                                             (“robustness” indicator)

                            INPRO                                                                         PRPP
                                                              common elements
                         ASSESSMENT                                                                    EVALUATION

                                                     NO            PR
                                                                                                 INTERACTION OF INPRO AND
                                                                                                     GIF PROLIFERATION
                                                                        YES                       RESISTANCE APPROACHES

Figure 3: Interaction of INPRO and GIF proliferation resistance approaches [4]

Figure 4: Dependencies of Measures in the GIF PR Evaluation Methodology and their
relation to INPRO User Requirements/Indicators [4]


Proliferation resistance is an important pillar of development and deployment of nuclear
energy systems. Further continuous efforts for developing and using proliferation resistance
assessment methodologies are expected.

PRADA plays an important role not only in further developing the INPRO PR methodology
but also in the effort for harmonizing the GIF and INPRO PR assessment/evaluation
methodologies. The draft of the final report of PRADA is expected to be prepared by the end
of 2010. An enhanced INPRO PR Methodology will have greater usefulness for both
technology holder and u technology ser Member States. Further close cooperation between
GIF and INPRO in this field will continue.

Above mentioned activities have been implemented in cooperation with international experts
and the IAEA staff. The followings are the last, but not the least of them. All of contributors’
efforts are appreciated.
Allan, C. International Atomic Energy Agency, Austria
Beatty, R. International Atomic Energy Agency, Austria
Cojazzi, G. Joint Research Centre, Italy
Depisch, F. International Atomic Energy Agency, Austria
Gang, Z. China Institute of Atomic Energy, China
Killeen, T. International Atomic Energy Agency, Austria
Sevini, F. Joint Research Centre, Italy

[1] IAEA TECDOC 1575 Rev.1 Guidance for the Application of an Assessment
   Methodology for Innovative Nuclear Energy Systems, INPRO Manual – Overview of the
   Methodology, 2008
[2] H.L. Chang and W.I. Ko, The First Year Progress Report of the INPRO Phase 2
   Collaborative Project, ROK1, “Proliferation Resistance: Acquisition/Diversion Pathway
   Analysis (PRADA)”, Presented at the INPRO Consultancy Meeting, IAEA, November
[3] H.L. Chang and W.I. Ko, The Interim Second Year Progress Report of the INPRO Phase
   2 Collaborative Project, ROK1, “Proliferation Resistance: Acquisition/Diversion Pathway
   Analysis (PRADA)”, Presented at the INPRO Consultancy Meeting, Jeju-City, Korea,
   June 2009
[4] Pomeroy, G, et al., Approaches to Evaluation of Proliferation Resistance of Nuclear
   Energy Systems, Proceedings of INMM (Institute of Nuclear material Management) 49th
   Annual Meeting, Nashville, TN, 2008


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