# NS&E 618 Treatment of LLW Class 3 - Regulations - PowerPoint by 26s66gVB

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```									Class 2
Review last week’s presentation
Review activity
Complete 8/29 slides
Origin of waste
Regulations
Homework

9/17/2012          NS&E 618 -- GAB     1
Definition of a Curie: the activity of 1
Radionuclides were found to have a
decay rate proportional to the number,
dN/dt = -λN (minus sign for decay, λ is
the proportionality constant)
dN/N = -λdt

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Solution to Activity
Integrate last equation
ln(N) = -λt
N = Noe-λt
Solve for λ, by choosing a time when
the initial population, No, has decreased
to half
N = 0.5No = Noe-λt(1/2), take logarithm,
ln(0.5) = -λt1/2
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Activity Solution Continued
Therefore, λ = -ln(0.50)/t1/2 = -(-0.693)/t1/2
λ = 0.693/t1/2
Therefore
N = Noe-0.693t/t(1/2)
Note: This is only true for the number of atoms, it is
not true for grams or mass. If you know the mass in
grams, you must first change to N
N = (6.023E23)*(mass in grams)/(Atomic mass)
Where the second term is the number of moles

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Activity Units
Finally, recall that the activity is
Activity = -dN/dt = λN = 0.693N/t1/2
t, time, is in seconds, 1 y = 3.15E7 s
The above will give activity in
transitions per sec which is definition of
Becquerel or Bq
1 Curie (from 1 g of Ra) = 3.7E10 Bq

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Observations on Activity
Note that typical masses of
radionuclides in LLW are pico to micro
grams
Typical half life is 30 years or 1E9 s
Typical activities
~ 6E23*1E-9 moles/(1E9 s *3.3E10) =
microCuries

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Alternate method of
estimating Activity
Work from old definition, 1 g Ra => 1 Ci
The mathematical solution states that Activity is
inversely proportional to half life
At. mass of Ra-226, t1/2 = 1600 y
If I had 1 g of Sr-90, t1/2 = 30 y, then
Activity(1 g of Sr-90) = (226/90)*(1600/30) =134
(compared to IDB value of 136.4)
Note: 1st term says lower At. mass, the more
atoms/g, and 2nd term says shorter half life, the
higher the activity.

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Remember this chart?
http://nucleardata.nuclear.lu.se/nuclear
data/toi/pdf/chart.pdf
The correct way to read it is to save to
your disk, open in Acrobat, and zoom in

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1 Ci of 1 MeV Gamma
= 1 R at 1 m
It’s really applicable to 2 Ci, not 1 but its close enough
Applicable to gamma that is not appreciably absorbed
Follows 1/r2 law for point source because gamma’s are
randomly generated and equal numbers must pass through
concentric spheres.
For a line source (pipe) it follows 1/r (concentric cylinders)
For plane source (floor or wall) it is 1/r0 or independent of
distance (until air absorption takes over)
If you measure outside a drum, it can be treated as a point
source if it is relatively uniform or you are far away (1 m)
If you look down a pipe through concrete, into a contaminated
liquid, the point source you see is all the radionuclides in a
volume through which the radiation can penetrate and you can
see. Penetration distance for 1 MeV ~ 1 foot

9/17/2012                  NS&E 618 -- GAB                          9
Geometry
Point source
1/r2

Line source
1/r1

Plane source
1/r0

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Origin of the Waste
Reactor operation, fuel storage, and reprocessing
Fuel rods occasionally fail (rupture or develop pin
holes)
Activated components corrode
Water coolant becomes contaminated
Reactors are decontaminated; the process aims to
dissolve extremely insoluble oxides and metals;
therefore, the solvents pose a serious solubility
problem
Water clean-up systems result in difficult to handle
resins and sludges.

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Typical LWR Commercial
Fuel Bundle. Probably a
14x14 in array weighing
around 1000 lbs
Stainless steel or zircaloy
tubes, 0.5 in. diameter,
contains uranium oxide
fuel.
Naval, production, gas-
cooled, sodium cooled, and
research reactors differ
significantly.

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High Level Waste
Includes Spent Fuel, first cycle raffinate
(FCR), and solids derived from FCR
Transuranic Wastes include in this course, but
mostly it is in the HLW course
FCR derived from fuel reprocessing
Subsequent handling and processing of HLW
results in LLW. The associated hazardous
chemicals make it MLLW.

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Fuel Reprocessing
Dissolve clad fuel, (dissolve fuel and
only)
Extract U, Pu, or both, or FP only
Fuel is measured in terms of MTHM and
MWd (burn-up)
Observe concentrations

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Pu Concentrations of Fuel
Depends on reactor
Commercial Reactors use 3.5 to 5 wt.% U-
235 enriched fuel
If you remove the fuel at 1% U-235, then Pu
may be around 2-3 wt.%
If you extract 99.5% of the Pu, you have
0.01% left in the waste
0.01% = 100 ppm -- TRU lower limit 2 ppm

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Other Sources
Space applications
Research applications
Weapons

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10 CFR 20; 10 CFR 60; 10 CFR
61
These Regulations tell when, what and
how well to Treat
These Regulations do not tell how to
treat, but the requirements for disposal.
We treat to meet the requirements for
disposal.

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Waste Management Regulations
• 10 CFR 20.2001 through 2005 in essence defines radioactive
waste by what you can do with Radioactive Material:
Keep
–      Transfer
–      Decay
–      Vent - if less than Table 2 of appendix B
–      Flush - if less than Table 3 of appendix B
–      Incinerate
–      Environmentally Safe 40 CRF 190
–      Dispose of per 10 CFR 60, or
–      Dispose of per 10 CFR 61

All are required for HLW treatment
In DOE, we must also include WIPP WAC

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Alternatives
Requiring                              Vent
Treatment
Incinerate

Material                •Use                 Transfer
•Process
•Store

Treat
Flush                 Dispose of

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10 CFR 20 Appendix B

•   Use for effluents
•   Note only low allowable concentrations
•   10E-8 to 10E-7 micro Ci/ml in air.
•   Appreciate that it is Safety Based
•   Human Safety takes precedence over Table
2 – 3 values

10 CFR 20 is primarily applicable to
the effluent streams, not disposal streams.
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Waste Disposal Regulations

• 10 CFR 60
High Level Waste NS&E 619
• 10 CFR 61
Low Level Radioactive Waste - scope of this class
• Also not included in class is UMTRAP, FUSRAP,
and NARM
•UMTRAP -Uranium mill tailings remedial action program
•FUSRAP – Formerly Utilized Sites Remedial Action Program
•NARM - Naturally Occurring and Accelerator-Produced Wastes

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10CFR 61.56 - General Waste Characteristics

• No cardboard containers
• No free liquid (< 1%)
• No explosives
• No toxic or pressurized (1.5 atm) gas
• No pyrophorics
• Minimum hazardous, pathogenic and infectious

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10 CFR 61 General Requirements
• License based on human health and safety (10 CFR 61.23)

• Performance Objectives (10 CFR 61.41-44)
– 25 mRem whole body dose or individual organ
– 75 mRem thyroid
– Protect inadvertent intruder (waste form)
– Long term site stability after closure
(waste form, no voids)

• Control Based on Waste Classes A, B, C
• If Greater Than Class C one should technically
go to 10 CFR 60, However, this is actually a
politically sensitive issue)

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10 CFR 61.56 - Specific Characteristics
(allocable to waste or container)

• Stability against slumping, collapse, or failure
of the unit
• Stability against moisture, microbes, radiation
• <1% liquid in container; or <0.5% in stable waste
• Minimum void volume

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The Problem
Transuranics (Np, Pu, Am, Cm) and
Actinides (Ac, Th, Pa, U plus TRU)
Long-lived beta/gamma emitters
Ultimately dominated by Actinides:
Am(241 and 243), Pu(239 and 240),
and Np-237
and, Fission and Activation products I-
129, Tc-99, C-14, Nb-94

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The Problem, cont.
First 1000 years, HLW has both high
Radiation is high enough to cause
material damage
Thermal is high enough to raise
temperatures to 700 - 800 C
After 1000 yr, HLW equivalent to TRU

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The Solution, HLW
Deep Geologic Disposal
10,000 -100,000 year confinement
Allocate first 1000 years to waste
container
Next 10,000 years to Waste Form
Next 100,000 years to Geologic Media

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The Solution, LLW
Near Surface Disposal
100 year institutional control
300 year waste form

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Geologically Stable Materials

NaCl              S
C                 Clays
Granites          Basalts (Glasses) Tuft
Shale, Schist
Phosphates                  Carbonates

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• Glass
• Bricks
• Hydraulic Cements

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Compare 10 CFR 61 Waste
Characteristics with:

• 10 CFR 60 (HLW)
and
• WIPP WAC

9/17/2012           NS&E 618 -- GAB   31

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