ML20203K416
| ML20203K416 | |
| Person / Time | |
|---|---|
| Issue date: | 02/25/1998 |
| From: | Phil Brochman NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| Shared Package | |
| ML20203K419 | List: |
| References | |
| FRN-63FR32600, RULE-PRM-71-11 AF59-2-004, AF59-2-4, NUDOCS 9803050079 | |
| Download: ML20203K416 (4) | |
Text
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l February 25, 1998 I -
MEMORANDUM TO: File FROM: Philip Brochman, Nuclear Engineer Origli.a1 /s/ by Spent Fuel Project Offico Office of Nuclear Maten Safety and Safeguar ",
SUBJECT:
ACRS QUESTIONS ON RULEMAKING TO REVISE 10 CFR PART 71.63 The attached questions were received on February 10,1998, from a member of the Advisory Committee on Reactor Safety (ACRS), Dr. Dana A. Powers. These questions pertain to a final rule to amend 10 CFR Part 71 to add vitrified high-level waste to the forms of plutonium which are exempt from the double containment requirement of 9 71.63(b).
Docket: PRM-71-11 :,
/sttachment: As stated Distribuition:
NRC f/c PUBLIC SFPO r/f M. Haisfield, INMS N. Dudley, ACRS
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i l To: N Dudley and T. Kress From: Dana A. Powers
Subject:
ACRS Review of
- Requirements for Shipptr; Packages Used to Transport Vitrified liigh Leve' "/aste (PRM-71-11)
Transportation of radioactive waste is not a high psionty topic for the ACRS and historically has been found by dispassionate analysis to pose relatively low iisk. It is, however, a very visible safety issue for the public and does mandate attention from Congress. I think therefore that we need to be careful about any changes to rules regarding the transpon of nuclear waste to assure that they are based on very sound science. I have some technical questions about the proposed final rule, " Requirements for Shipping Packages Used to Transport Vitrified High Level Waste' (PRM-71-11). I think we need to have satisfactory answers to these questions before we conclude that this rule can go fonvard without ACRS review. My questions are:
- The hazard analysis done on the proposal for not zequiring double containment of vitrified waste assumed based on results of tests done at Savannah River that transportation accidents would not yield significant amounts of plutonium contaminated fines. It is, known, however, that the amount of fines produced by glass impacts depends very much on the glass properties. What precautions are to be taken to assure that vitrified waste has propenies similar to those of the glasses tested at Savannah River? What precautions are to t>e taken to assure that loading of the borosilicate glass does not lead to devitrification of this unstable glass with the consequent formation oflocalized stress risers in the glass? What precautions will be taken to assure that the thermal stresses in the glass at the time ofimpact are bounded by the thermal stresses in the ,11 ass tested at Savannah River?
- To my knowledge, the DOE has not selected a partiet.lar geometry and configuration for vitrified waste logs. Configuration twice as large and ten times as large es that now made at Savannah River have been considered at other sites including the DOE sites to be affected by this proposed rule. The decision to use private contractors to fabricate vitrified waste logs could also lead to some substantial variability in the susceptibility of the vitrified waste to fines formation in the event of a transportation accident. Why, then, do we feel the testing done at Savannah River is in any sense bounding?
- Vitrified waste canisters are unavoidably contaminated with plutonium-bearing materials du-ing the fabrication or loading process. Does this contamination disqualify the stainless steel as the first container, much less the only container, in connection with the double containment rule? Was the external contamination of the canisters recognized in the assessment of accident risk?
- Does thermal shock to the vitrified waste in the event of fire during a transportation accident contribute to the formation of respirable fines contaminated with plutonium? What tests have been done on this matter and how do they bound the range of possible accideats?
Attachment ,
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- Did the risk analyses take into account the contributions of americium to the dose from
- the plutonium waste form? What limits will be placed on the contamination of the waste by radioactive isotopes having more penetrating radiation than plutonium such as the radioactive isotopes of Sr, Cs, and Tc? Will not the contamination by these isotopes affect the risk?
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- The environmental analysis asserts the increase in risk caused by transportation of the singly contained vitrified waste is 0.5% of normal transportation risk. Quantitative health
. objectives for nuclear facilities assert a goal for the NRC regulations of 0.1% of normal accident 2
risks both with respect to prompt fatality and latent fatality. Why is this 5 fold difference in the l risk limit tolerable?
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- Uncertainty analyses of the quantitative assessments of risk need to be provided, i
1 i it may well be that answers to all of these questions are readily available in the supporting documents and can be ,ssembled easily, if not, I think the ACRS should hear about the rule change and that during the hearing answers to the above questions should be provided.
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Mail Envelope' Infos (34E050EC.2DB : 24 : 7.18)
Subj9ct ACRS Questions creation Date: 2/10/98 8:06am From: -- Noel D.2dley created By: TWD1.TWP2:NFD Recipients Post Office WND1.WNP7 PGB (Philip Brochman)
- Domain. Post Office Route WND1.WNP7- WND1.WNP7 Files Sise Date & Time GLASS 6.WPD 6181 02/09/98 10
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