ML20245G032
| ML20245G032 | |
| Person / Time | |
|---|---|
| Issue date: | 07/20/1989 |
| From: | Rouse L NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Cool D NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| References | |
| NUDOCS 8908150169 | |
| Download: ML20245G032 (2) | |
Text
__
JUL 2 012
. MEMORANDUM FOR:
Donald A. Cool, Chief Radiation Protection and l
Health Effects Branch Division of Regulatory Applications, RES FROM:
Leland C. Rouse, Chief Fuel Cycle Safety Branch L4 vision of Industrial and Medical Nuclear Safety, NMSS
SUBJECT:
CHEMICAL T0XICITY OF URANIUM HEXAFLUORIDE RELATED TO RADIATION DOSES On June 1,1989, Alan Roecklein transmitted a draft report on the health effects of uranyl fluoride to Dick Cunningham, and asked for any comments.
suggestions, or requests for further work. The report was in response to the l
second part of our Jul.y 8,1988 request to Messrs. Morris and Arlotto for technical support en the development of guidance levels for uranium uptake i
consequent to accidental uranium hexafluoride releases.
l The results of the work are an important part of the criteria and guidance l
necessary for licensing reviews of uranium enrichment plant applications, and the results shculd be published as a NUREG report. We believe this can be accomplished by tightening up some of the wording of the draft report and by.
consideration of the following additional comments by my. staff.
We think there should be a discussion of the lack of any direct comparability between the health effects from the 25 rems dose used in 10 CFR Part 100 and the chemical health effects from any acute exposure to hydrogen fluoride hydrolyzed I
from uranium hexafluoride. The organs affected, the type of injury, and the i
timing of health effects are all different. Furthermore, the relationship of the respective exposure / health effects is different.
For example, doubling the rediation dose might increase the number, but not the severity, of health effects; 4
doubling the exposure to hydrogen fluoride might increase the severity from an 1
irritation to permanent injury. This phenomenon also implies that uncertainties in the exposures resulting from accidental releases may be more important in the uranium hexaflucride case.
4 The lack of direct comparability also suggests that it is unnecessary to discuss, in the section on effects of the radiation doses in 10 CFR Part 100,-
details about non-comparable health effects, in particular those resulting l
from doses far different than those of interest. Also, unless information is available about the health effects on persons other than adults from exposure to hydrogen fluoride, it may be inappropriate to discuss health effects on
)
embryos, fetuses, and children from radiation exposure.
In the section on chemical toxicity of uranium hexafluoride and its products, effects of UO,F onfetusesmightbediscussedbothinterms'oftransferofflourideanduf,abium to the fetus and in terms of the effects of inbalances in the mother's metabolism due to flouride and/or uranium poisoning. With regard to HF acid burning of the lungs, a child's lung mass and breathing rate might alter the sensitivity relative to adults.
OF0f
)b
$h69 Q20 yOi I t PDR NE FRE CENTE CDPY
[
J Donald Cool 2
.The subsection on radiation dose from uranium, which is part of-the section on chemical toxicity of uranium hexafluoride and its products, needs an introduction to the question posed. Footnote 4 to 10 CFR Part 20, Appendix B should provide the source of an introduction. The discussion should also make it clear that, while radiotoxicity overrides chemical toxicity for chronic exposures to soluble forms of uranium only above about 5% U 235 enrichment, chemical toxicity is the limiting factor for acute exposures regardless of-U 235 enrichment. The introduction of U-236 from recycling spent fuels might affect this conclusion. Since the concept presented in this-subsection has not been publicized before, we recommend that the assumptions and the reasoning used be verified before publication..
The conclusions section contains a design basis accident to demonstrate distances at which. hydrogen fluoride exposures exceeding the amount equivalent to 25 rems would occur. While inclusion of such an example is useful, placing it in the conclusions section may improperly imply that it is the design basis-accident that the NRC will consider.
Please contact Jerry Swift, Section Leader for Advanced Fuel and Special-Facilities Section, if you wish more information about any of these comments.
OrfdialS%nad by Leland C. Rouse, Chief Fuel Cycle Safety Branch-Division of Industrial and Medical Nuclear Safety, NMSS Distribution:
NRC File Center PDR LPDR NMSS R/F IMSB R/F IMAF R/F JSwift PLoysen CNilsen FSturz FBrown b
0FC :IMAF [
- IMIF
- IM F
- IMS //_/
l L NAME : Ploy 57en:jc :JJSwift own
- LC'ouse i
__---:............:............j DATE :7//1/89
- 7/ /89-
- 7/l$/89-
- 7/@/89 OFFICIAL RECORD COPY L_1___ _ _
_