ML20023C073
| ML20023C073 | |
| Person / Time | |
|---|---|
| Issue date: | 04/15/1983 |
| From: | Higginbotham L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Rouse L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| REF-WM-3 NUDOCS 8305090617 | |
| Download: ML20023C073 (4) | |
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APR 151983 DiSIRIBRTION noas y1 WMLi. r/f WM s/f /
414.8.2/TJ/83/04/04/0 TCJohnson PHLohaus LHigginbotham REBrowning MEMORANDUM FOR:
Leland C. Rouse, Chief PDR g\\.2 5" g Advanced Fuel & Spent Fuel 73 Licensing Branch FROM:
Leo B. Higginbotham, Chief Low-Level Waste Licensing Branch (Return to n, c23-SS
SUBJECT:
REVIEW 0F EVALUATION TO SELECT SOLIDIFICdiluh AbtNI FOR WEST VALLEY In response to your memorandum dated March 24, 1983, we have reviewed the
" Selection of the West Valley Demonstration Project Low-Level and Transuranic Waste Form, Rev. 1."
This document had been transmitted to T. Clark from W.H. Hannum of the Department of Energy (D0E).
The document on the West Valley waste form selection is very general in nature. There is insufficient technical data in the document to judge the adequacy of either cement or asphalt for the solidification of West Valley wastes. However, we have provided several comments which should be helpful to DOE.
The request to provide comments on the acceptability as it relates to 10 CFR Part 61, of either asphalt er cement for use with transuranic wastes, is difficult without knowledge of the proposed disposal site or disposal methods. As we have stated in 10 CFR Part 61, we would evaluate the acceptability of wastes which exceed Class C limits, on a case-by-case basis considering the proposed disposal site conditions, waste form and method of disposal.
The evaluation assumes that the the TRU limit for the disposal of West Valley wastes at West Valley would be 100 nCi/gm. The TRU Limit in 10 CFR Part 61 was based on a complex series of scenarios which assumed as a t
source term commercial wastes as would be projected through the year 2000.
If the West Valley wastes are significantly different from the 10 l
CFR Part 61 Source Term, the 100 nCi/gm TRU Limit may be inappropriate.
If you have any questions, please contact myself (74300) or P. Lohaus (74500).
Original Signca E7 Leo B. Higginbotham, Chief g 5 g 7 830415 Low-Level Waste Licensing Branch WM-3 pg I
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Comments on the " Selection of The West Valley Demonstration Project Low-Level and Transuranic Waste Form, Rev.1"
- 1. General The Low-Level Waste Regulation, 10 CFR Part 61, establishes waste form requirements based on a waste classification system. Class A wastes need to meet the minimum waste form requirements. Class B and C wastes need to be in a stable form. The selection document does not include a characterization of the expected wastes. For the purposes of this review, it has been assumed that any of the expected waste streams could be Class B or C wastes and that stable waste forms are desired.
- 2. 2nd Para., P. 1 For Class B and C wastes our Technical Position on Waste Form (TP) provides a recommended test program for demonstrating stability to meet the requirements in 10 CFR 61.56 (b). The TP recommends test methods for demonstrating that a waste form will remain structurally stable under the expected disposal conditions which include exposure to radiation, mechnical loads, moisture and microbial activity. The data presented in this paragraph does not address all the areas for den.onstrating stability of Class 8 and C wastes.
The recommended leach test results in our revised TP are given in terms of the leachibility index as calculated in accordance with the draft ANS 16.1 standard. We are unable to directly compare the leach rates given without knowledge of the cumulative releases over time.
10 The radiation exposure level of 10 Rads is very high for bitumen products. The mechanical integrity following the proposed total accumulated dose should be tested to ensure that its structurally stability has not been affected.
The supernatant contains primarily nitrates and nitrites. Leach testing should include the release of these chemicals, in addition to the release of radioactive species. The release of these chemicals should be considered in assessing suitable disposal options.
- 3. Top Incomplete Para., P. 2 The statement that process controls are important for the bitumen process should also include the cement process. Process control is intended to ensure that the solidification formulations will produce a consistent and
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414.8.2/TJ/83/04/04/0 acceptable waste form for the applicable, proposea waste streams.
Process control is essential for all solidification processes.
In order to develop a process control program, the expected waste stream chemistries should be enveloped and testing performed to qualify each applicable formulation.
- 4. Second and Third Para's, P. 2 The solidification of nitric acid, organics and decontamination solutions may not be straightforward. These wastes, depending on their chemistry, may make solidification difficult and affect the quality of the resultant product.
Consequently, the decision to use these chemicals should reflect the capability to process these streams. Tests should be performed to ensure that the proposed solidification agents will properly solidify these wastes.
It should also be noted that decontamination solutions generally contain chelating agents to increase the solubility of specific metals. These chelating agents can increase the mobility of radioactive species in a burial environment. Therefore, the disposal of these wastes should be considered in the selection of any decontamination solution used at West Valley.
The rule, 10 CFR Part 61, requires that wastes containing greater than 0.1 percent by weight of chelating agents be specifically marked. The acceptability for disposal of these wastes would be dependent on the proposed disposal environment, operations and waste form.
- 5. Top Incomplete Para., P. 3 Testing needs to be performed to confirm that the West Valley decontamination solutions can be solidified into acceptable waste forms.
- 6. Second Full Para., P. 3 Again testing needs to be performed to confirm that all proposed waste streams can be solidified into acceptable waste forms. Decommissioning operations could generate wastes containing non-routine chemicals which could cause difficulties in solidification.
- 7. Third Full Para., P. 3 There has been very little nuclear experience using evaporators wh1ch produce 50 weight percent sclids. However, evaporation experience has indicated that, many times, estimates of volume reduction have been overly optimistic. These practical problems should be reflected in the 1FC :
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414.8.2/TJ/83/04/04/0 selection of a solidification agent, since these problems may have large economic effects.
The last sentence states that a cement facility utilizing evaporation is capable of providing greater overall volume reduction than a bitumen facility. Such a situation obviously depends on the individual waste streams and the type of asphalt system assumed. Some asphalt systems claim substantial volume reduction factors.
- 8. General It is not clear why polymer solidification agents were dismissed summarily in Reference A. Polymeric binders like Vinyl Ester Styrene (VES), have been shown to be very effective for solidifying some decontamination solutions. VES may be a more generally suitable solidification agent considering the wide chemical spectrum in the expected West Valley wastes.
- 9. Last Para., P. 4 It is not clear why the evaporator was assumed for use with the bitumen facility. Most bitumen systems inherently volume reduce aqueous waste streams by evaporation. Preconcentration would be unnecessary unless it was used to increase the effective capacity of the bitumen solidification process.
- 10. First Incomplete Para., P. 5 If wastes are evaporated to complete or near complete dryness, additional water may need to be added for hydration of the cement. It is assumed that testing will be performed to obtain the appropriate waste formulations for this waste.
The evaluation states that if all the proposed West Valley waste streams were included, the analysis would favor cement. This is not clear considering the potential difficulty in solidifying waste streams containing chemicals which may be incompatible with cement.
In order to achieve adequate solidification, high waste to cement ratios may not be appropriate.
Low waste loadings could result in substantial cost penalties for the cement option. Obviously, the effectiveness of cement I
solidification can only be determined by testing using the expected waste chemistries.
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