ML20055G921
| ML20055G921 | |
| Person / Time | |
|---|---|
| Issue date: | 07/20/1990 |
| From: | Liza Cunningham Office of Nuclear Reactor Regulation |
| To: | Knapp M, Norelius C, Stohr J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| FRN-55FR31113, RULE-PR-20 NUDOCS 9007240346 | |
| Download: ML20055G921 (3) | |
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Malcolm R. Knapp, Director, DRSS, RI J. Philip Stohr. Director, DRSS Region 11 Charles E. Morelius.. Director DRSS, Rlll Authur B. Beach, Director, DRSS, RIV Ross A. Scarano, Director, DRSS, RV
.s FROM:
LeMoine J. Cunningham, Chief m
Radiation Protection Branch Divisioh of Radiation Protection and Emergency Preparedness, NRR
SUBJECT:
DETERMINING COMPLIANCE WITH THE OCCUPATIONAL DOSE LIMITS IN 10 CFR 20.101 The purpose of this memorandum is to re; erste established NRC requirements and positions with respect to determining occupational doses for comparison with the limits of 10 CFR Section 20.101.
This reiteration is prompted by the continuing attempts by somc licensees, in i
determining doses for comparison with the limits of 10 CFR 20.101, to use assumptions and positions other than those established by the NRC. For example.
in a recent enforcement case, the licensee argued that an estimate of the actual thickness of a contaminated area of a thumb, and not 7 mg/cm2, should be used to calculate the skin dose for comparison with the limit in 10 CFR 20.101.
To mention only a few other examples, in.other cases licensces have argued that the dose limit for the hands and forearms, feet and ankles applies to the lower leg above the ankle',-that the "whole body" dose limit did not apply to the
' thigh of a particular worker because.of the absence of red bone marrow in the lower part of the femur of an individual, and that the area for averaging dose I
i' from a hot particle on the skin should be greate than 1 cat.
Questions as to which of the three different limits in 10 CFR 20.101 applies in a particular situation have arisen in a number of cases.
In general, if the dose is to some part of the body other than the hands and forearms, feet and ' ankles, the "whole-body" limit (1.25 or 3 rem per quarter) and " skin ~
ot the whole body" limit (7.5 rem per quarter) apply (Memo. from L. J. Cunningham, NRR, to R. R. Bellamy, Region I, et al., June 22,1989).
CONTACT:
John Buchanan, NRR 492-3184 9c
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The " hand and iorearm" includes the hand, the arm below the elbow and the elbow. The dose from each appendage may be separately determined and compared to the limit.
(IE Information Notice No. 63-59, September 15,1983).
The term " extremities" is not used in 10 CFR Part 20; however, if this term is it should be understooc used in the context of the dose limits of 10 CFR 20.101} rom L. J. Cunningham, hkR, to mean " hands and forearms, feet and ankles".
(Memo.
to R. R. Bellamy, Region 1, et al., June 22,1989).
Assumptiers concerning tissut' ctpths for oose determinations for regulatory purposes are provided in the Instructions for Preparation of NRC Form 5 litem 5) on the back of HRC Form 5.
The NRC Office of the General Counsel (OGC) has conf 4meo that these instructions are regulatory requirements (Memo.
f rom J. L4 German, DGC, to P. McKee, IE, January 13,1987).
An area of I cm2 has been established f or calculating skin doses for comparison' with the dose limits f or the skin of the whole body or for the hands and forearms, itet and ankles when the skin exposure is highly localized and non-unif orm, such as in cases of exposures f rom hat particles on or near the skin.
(IE Iniormation Notices Nos. 86-23 April 9,1986, ano 87-39, August 21, 1987).
In general, the parameters specified in regulatory positions for determining dose for comparison with limits have been established conservatively for protection of all workers regarcless of race, sex, age, or other individual differences. Consiceration 01 differences involving race, sex, and age has the potential 1or violating state and federal laws prohibiting discrimination on the basis of race, age, and sex.
Having reiterated the current regulatory positions f or these issues, it is also apprcpriate to note that some will be changing in the nt,t to distant future. For example, the revised Part 20 will redefine the lower extremities and a change to Part 20 will establish new limits for hot particle exposures.
Also, the revised Part 20 although specifying a weighting f actor of 1.0 for external "whole body" exposures, allows the approval of other weighting factors on a case-by-case basis until such time as specific guidance is issued by the NRC.
Although NRC-established requirements and positicns must be used in determining compliance with the limits of 10 CFR 20.101, licensees may, of course, use other assumptions in determining coses for purposes other than for comparison with NRC limits. The results of these calculations may be entered, as supplemental information, in occupational cose records. Such supplemental information may be used to obtain a " dose" value (such as the eff ective dose equivalent) that is more representative of the actual risk to an individual worker in a particular case than the dose value that must be used for comparison with the dose limits
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-;31-i of 10 CFR 20.101.
It also is possible that-the NRC may consider such $upplemental information, depending on the circumstances of the individual case, when-
< exercising enforcement discretion to determine the' nature and severity of the enf orcement action to be taken v'en the dose limits of:10 CFR 20.101 have been 3
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exceeded.-
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LeMoine J. Cunningham, Chief-Radiation Protection Branch Division-of Radiation. Protection-and Emergency Preparedness, NRR-l DISTRIBUTION:
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