ML20058K049
| ML20058K049 | |
| Person / Time | |
|---|---|
| Issue date: | 02/09/1989 |
| From: | Sniezek J Office of Nuclear Reactor Regulation |
| To: | Jordan E Committee To Review Generic Requirements |
| References | |
| NUDOCS 8902170071 | |
| Download: ML20058K049 (24) | |
Text
_
SD 0 q
as.
\\
UNITED 8 TAT 88 l
'4
.[
NUCLEAR RE@ULATORY COMMISSION evannewetow.o.c.senes 7e' g
k....
l e
FEB 9 %I99 MEMORANDUM FOR: Edward L. Jordan Chairman Comittee to Review Generic Requirements FROM:
James H.-Snierek. Deputy Director Office of Nuclear Reactor Regulation
SUBJECT:
GElG IC LETTER AND INTERIM STANDARD CONCERNING HOT PARTICLE EXPOSURES OF SKIN The subject draft generic letter is included as Enclosure 1 for your attention.
We request that the Committee to Review Generic Requirements (CRGR) review the proposed generic letter under the provisions of the CRGR charter.
The purpose'of the' generic letter is to inform licensees of an effective change (increase) in existing limits on occupational exposure of skin to radiation emitted f rom hot particles. This change is warranted because of the relatively low risk associated vith these hot particle exposures and the additional whole body exposures that may be resulting from monitoring workers for hot particle contaminatitn to prevent exposures of the skin in excess of the current applicable 1 mits._ This effective change of the relevant limits will be accomplished by inplementation of an irterim standard that will be used by the NRC staff in exercising its enforcement discretion in cases involving potential overexposures of this type. This interim standard will be transmit-ted to licensees as an enclosure to the generic letter.
Please perform the formal CRGR review of the issues presented in this draft generic letter. CRGR requirement item IV.B is provided as Enclosure 2.
Also included as Enclosure 3 is a draft staff paper that will be sent to the Comission af ter resolution of CRGR comments and recommendations on the generic letter.
0?GCG CONTACT:
)(O John D. Buchana R
') \\\\
492-1097
\\
qQ PI J
(f' Q
h Sb A
/
[
f
.i
+
I#
f Edward L. Jordan.
s 4
If you have any questions, please contact y staff.
Orl inal sl ned by l
E E
hmes H. ?nittek James H. Sniezek, Deputy Director Office of Nuclear Reactor Regulation l
Enclosures:
l
. 1 ', Draft Generic Letter and Interim Standard 2.
CRGR Package 3.
Draft Commission Paper Distribution:
JH5nitzek, NRR FJMiraglia, NRR FPGillespie, NRR CHBerlinger, NRR FJCongel, NRR j
LJCunningham, NRR JEWigginton, NRR i
THEssig, NRR JDBuchanan, NRR WDTravers, NRR RJBarrett, NRR 5
BMMorris, RES-AKRoecklein, RES JBell, RES JLieherman, OE SATreby, OGC.
RECunningham, HMSS.
MVFederline. OCM/KC Central Files RPB R/F l
Record Note: This 1stter and all enclosures were edited by a technical editor, J. F. Beeson, November 29-30, 1988, and those editorial comments have been l-considered.
l-
- see previous concurrence p
DOEA:llRR
- 0GC WADT:NRR D
CHBerlinger SAireby FJMiraglia J
zek 02/01/89 12/15/88 02//$/89 02/ /89
- RPB:DREP
- SC:RPB:DREP
- C:RPB:DREP
- DRA:RES
- D:DREP
- D:0E JDBuchanan:bt JEWigginton LJCunningham BMMorris FJCongel JLieberman 12/06/88 12/06/88 12/06/88 12/14/88 01/25/89 01/19/89 i
ENCLOSURE 1 i
TO:
- ALL REACTOR LICENSEES AND APPLICANTS
SUBJECT:
INTERIM STANDARD FOR OCCUPATIONAL EXPOSURE OF THE SKIN TO RADIATION FROM SMALL RADI0 ACTIVE PARTICLES (HOT PARTICLES)
(GENERIC LETTER 88-XX) i 1
The purpose of this letter is to inform you of the NRC staff's position on en-forcement of limits on occupational exposure of the skin to radiation emitted from small radioactive particles, commonly known as hot particles.
As defined in this letter, a hot particle means a discrete radioactive fragment.
The NRC plans to amend 10 CFR Part 20 to provide a new limit for exposure of the skin by hot particles.
In the interim until this amendment to 10 CFR Part 20 becomes effective, the interim standard that is enclosed with this let-ter will be used by the NRC staff in taking enforcement actions for violations involving exposure of the skin to radiation emitted from hot particles.
The interim standard provides that, for a single hot particle exposure of an individual, the NRC will enforce a limit on doses to the skin of 50 rad aver-aged over 1 cm2 at a depth of 7 mg/cmt.
A notice of violation will not be is-sued for a single hot particle exposure of an individual below this limit.
BACKGROUND Since about mid-1985, many nuclear power stations have detected contamination of individuals and their clothing by small, usually microscopic, highly radio-active particles with relatively high specific activity (hot particles).
Hot particles arise primarily from two major sources:
degraded fuel (containing fission products) and neutron-activated corrosion and wear products (e.g.,
Stellite).
The increased incidence of detection of hot particle contamination has coincided with the increased use of new high-sensitivity whole-body ew-
--v,,
y-a
)
personal contamination monitors and the attendant increase in the probability of detecting hot particle contamination on a worker. These high sensitivity monitors are used in 95 percent or more of U.S. power reactor facilities, and 80 percent or more of commercial nuclear power plants have detected fuel fragments, cobalt-60 particles, or both.
In an earlier survey by the Electric Power Research Institute (EPRI), only 17 of 61 nuclear power plants surveyed reported no hot particle problems.
(Although all hot particles reported to the NRC have been associated with nuclear power plants, this letter also is being sent to non power reactor licensees because of the possibility of hot particle exposures at their facilities).
t Information concerning hot particle exposures and resulting doses and control of hot particle contamination has.been provided in two NRC information notices:
IE Information Notice No. 86-23 " Excessive Skin Exposure Due to Con-tamination with Hot Particles" (April 9,1986) and NRC Infomation Notice No. 87-39, " Control of Hot Particle Contamination at Nuclear Power Plants,"
(August 21,1987).
Other information concerning hot particle events and con-trol has been provided to industry by the Institute of Nuclear Power Operations (INPO).
Numerous papers concerning hot particle contamination have appeared in the technical literature in recent years.
NRC regulations, in 10 CFR 20.101(a), include limits on occupational exposure of the skin. These regulations are based on the National Council on Radiation Protection and Measurements (NCRP) recommendations in National Bureau of Stan-f dards (NBS) Handbook 59, (NCRP Report No. 17) " Permissible Dose from External Sources of Ionizing Radiation," published in 1954, with an addendum published in 1957.
For purposes of dose limitation, NBS Handbook 59 considered the sig-nificant area of skin in the region of highest dose rate to be I cm2 and the assumed average depth of the basal cells for purposes of dose calculation to be l
l 7 mg/cm2 Therefore, the NRC staff has considered the 1-cm2 area, including the region of highest dose, and the depth of 7 mg/cm2 to be appropriate for calculating skin dose to determine compliance with the limits of I
10 CFR 20.101(a) applicable to skin; this information was included in IE Infor-mation Notice No. 86-23 and reaffirmed in NRC Information Notice No. 87-39.
l l
l 2
In'its Publication 26, the International Commission on Radiological Protection (ICRP) discusses the assessment of dose to the skin and recommends the use of a j
depth of 7 mg/cm2 for this assessment.
For the situation in which the dose distribution is extremely non-uniform, as in the case of a hot particle on the skin, the NRC staff understands the ICRP recommendations to be (1) that the local distribution of absorbed dose (which involves a very steep dose gradient i
-and area much less than 1 cm2) should be assessed, but not compared to the dose (equivalent) limits and (2) that an estimate should be made of the dose equiva-lent averaged over 1 cet and that this value should then be compared to the dose equivalent limit.
An ICRP task group on the biological basis for radia-tion protection limits for skin is now studying the question of hot particle J
exposures and may provide additional recommendations on this subject within about a year.
NCRP Report No. 39 published in 1971, superseded NBS Handbook 59 (NCRP Report No. 17).
NCRP Report No. 39, like NBS Handbook 59 and ICRP Publication 26, recommends that " external radiation of low penetration could reasonably'be av eraged over a one square centimeter area" and that the " depth of reference is normally taken as the mass thickness of 7 mg/cm2." NCRP Report No. 91, "Recom-mendations on Limits for Exposure to Ionizing Radiation," published in 1987, superseded NCRP Report No. 39 and contains recommendations on radiation expo-sure limits that replace the recommendations of NCRP Report No. 39. However, NCRP Report No. 91 does not address the question of the area or depth to be i
used for assessing dose to the skin, nor does it otherwise address the question of hot particle exposure of skin.
Furthermore, the NCRP, in its draf t NCRP Report No. 101, (which is subsequently discussed), states that the " existing l
limits" of NCRP Report No. 91 "are overly restrictive" for very small areas of skin irradiation such as the irradiation that occurs with hot particles.
Both ICRP Publication 26 and NCRP Report 91 recommend an annual dose equivalent limit of 50 rem (occupational exposure) for skin to prevent (unacceptable) non-stochastic effects.
In a number of cases, occupational exposure of skin to radiation from hot par-ticles has resulted in doses to the skin in excess of the dose limits of 10 CFR 20.101(a) for the skin of the whole body and for the hands and forearms l
3 l
l
and feet and ankles.
In its enforcement actions for cases of overexposures from hot particles, the NRC staff has exercised enforcement discretion in rec-ognition of the lower risk from exposure of the skin to radiation from a hot particle as compared to the risk from exposure of larger areas of skin. This enforcement discretion has resulted in notices of violation for exposures that have had lower severity levels than would have been the case if larger areas of skin had been involved.
In regard to hot particle exposures of skin, the NRC staff recognized inadequa-cies in 10 CFR Part 20, the NCRP recommendations on which 10 CFR Part 20 was based, and subsequent NCRP and ICRP recommendations.
Because of these inade-quacies, the NRC staff, in March 1987, asked the NCRP to study the health sig-nificance of exposure from hot particles on the skin and to provide recommendations based on the findings of this study.
An NCRP subcommittee per-formed this study, and the NCRP provided a draft document entitled
" Recommendations on Limits of Exposure to ' Hot Particles' on the Skin" to the NRC on June 17, 1988.
The current 10 CFR Part 20 dose limits for skin and the NRC staff postMon on the method for calculating dose to skin from hot particles for comparison with j
the skin dose limits are considered by many to be too restrictive.
In general, concern has been expressed that the dose calculated in this manner does not l
adequately express the relatively low risk for those hot particle exposures that have occurred and that have been determined to be in excess of the regula-tory limits.
Industry representatives have expressed a concern that, as a re-suit of the current regulatory position, an unduly high level of attention and emphasis is being given to hot particles and hot particle doses at nuclear power plants.
These representatives have indicated that this attention and emphasis is causing unnecessary fear and concern among nuclear power plant workers.
Other concerns expressed by industry are costs and additional radia-tion exposures of workers (from sources other than hot particles), "inconsis-tent with ALARA principles," that could be substantially reduced by a change in the NRC position on hot particle exposures.
In some licensee efforts to avoid overexposures from hot particles, workers are being monitored more often for j
I hot particles during work in radiation areas that have the potential for hot particle exposures. This more frequent monitoring increases the time workers 4
]
spend in radiation areas and thus increases "whole body" radiation exposures.
The results of industry surveys reported to the NRC by the Nuclear Management and Resources Council (NUMARC) indicate that implementation of the new limit recommended in draf t NCRP Report No.101 for exposures resulting from hot par-ticles on the skin would tesult in an estimated reduction in whole-body dose of I
about one person-rem per year per nuclear power plant unit.
(For1987,the average total collective dose per unit was 420 person-rem.) Industry represen-
- tatives have emphasized that a change in the NRC position would not result in a i
decrease in the protection of workers or the general public nor in the controls j
that have been established to prevent hot particles from being transported offsite.
The NRC plans to consider the recommendations in NCRP Report No.101 in revis-l ing appropriate sections of 10 CFR Part 20.
However, the NRC recognizes that f
it will be at least 2 years until this revision can become effective and be-lieves that, in the interim, it is appropriate for the staff to use an interim standard in the exercise of its enforcement discretion regarding hot particle exposures of the skin.
i The NRC considered implementing the recommendations in draft NCRP Report No.
101 in an-interim standard for hot particle exposures of skin.
However, the NRC has decided, for a number of reasons, that it would be inappropriate to implement these NCRP recommendations in the draft report at this time.
In-stead, the interim standard enclosed with this letter, in effect, changes the limit for exposure of the skin to radiation from hot particles from 7.5 rem (skin of the whole body) or 18.75 rem (skin of the hands and forearms and feet and ankles) per calendar quarter to 50 rad per hot particle exposure.
The following considerations led to the decision to use a 50-tad limit rather than the NCRP-recommended emission limit for the interim standard, 1.
The recommendations in draft NCRP Report No. 101 include significant depar-tures from past radiation protection standards that should nct be implemented by the NRC without the opportunity for public comment provf ed by the rulemaking process.
These departures include (a) the establishment of a radia-tion protection limit that could allow some observable non-stochastic effects 5
. + - -
(offacts that the NCRP considers to be of negligible consequence), (b) the ex-pression of the limit in tems of beta particle emission rather than in terms of dose or dose equivalent, and (c) the absence of a safety factor in the value for the limit.
r 2.
NCRP Scientific Committee (SC) 80-1, which prepared draft NCRP Report No. 101, is considering some possible revisions to the report. At the time-this generic letter is being prepared, these revisions and the final report are not available.
3.
The NCRP recommendations are limited (consistent with the NRC request for these recommendations) to the case of a hot particle on (in contact with) the t
' skin. The NCRP recommt ndations do not apply to hot particles near, but not on, the skin (e.g., parti:les on hair or clothing).
The NRC staff plans to request the NCRP to study and provide recommendations on situations involving hot par-ticle exposure that were not dealt with in draf t NCRP Report No.101. However, in the interim, the staff believes that an interim standard that is less re-3 strictive than the current limits of 10 CFR Part 20 should apply to situations involving a hot particle on hair or clothing, as well as to situations in which a hot particle is on the skin.
{
4.
As recognized by NCRP SC 80-1, there are wide variations in the data con-sidered by SC 80-1 in reaching its recommendations, and additional research is needed on the biological effects of hot particles and the dosimetry of hot par-ticles.
The NCRP set the emission limit for a hot particle on the skin at the threshold for ulceration; however, the NCRP (in the June 1988 draft) did not provide an estimate of the uncertainty associated with the threshold value nor did it incorporate a safety factor in the recommended limit to preclude exceed-ing.this threshold. Also, as mentioned previously, a task group of the ICRP, on the biological basis for radiation protection limits for skin, is studying the question of hot particle exposures and may complete its work within about a year.
(The recommendations of the ICRP will not necessarily be the same as those of the NCRP in its Report No. 101).
5.
The NRC staff believes that the effective limit for hot particle exposure in an interim NRC standard should be conservative considering the uncertainty l
6
1 j
about the value that will be selected for the final rule change.
The selected value of 50 rad is conservatively below the approximate dose (at 7 ag/cm2 aver-aged over 1 cm2) of 500 rad (for fission products) that corresponds to the NCRP-recommended emission limit for a hot particle in contact with the skin.
6.
The selection of the 50-tad dose as a conservative, interin value is sup-ported by the results of studies by English investigators of the problems asso-ciated with localized skin exposures. With respect to dose limitation of such exposures, one of these investigators has stated that "Our results...would in-dicate that for acute single exposures, limitation of the dose to 0.5 Gy over 1 cm2 to a basal layer at a depth of 70 pm, would prevent sacroscopically visi-ble non-stochastic ef fects, other than possibly a transient ' point' erythema."
[
(J. Wells, Brit. 1,Radioloo.y Supplement 19, p. 149, 1986).
Similarly, another of these investigators has stated that "the data appear to support an extension of the ICRP dose averaging procedure (over 1 cm2 in the basal layer) to non-uniform exposures.
Acute exposures, even from the smallest sources, are highly unlikely to produce a detrimental skin response if limited to the 0.5 Gy.
annual dose limit recommended by the ICRP." (M. W. Charles, J. Soc. Radio 1. Prot. 6 (2), p. 80, 1986).
Considering the radiation doses in the cases to date of hot particle overexpo-i sures, all doses that have been below the NCRP-recommended emission limit are also below the interim 50-tad limit.
In one additional case, the NCRP limit would not apply (because the particle was not on the skin), but the dose in this case while in excess of the 10 CFR 20.101(a) limits was less than the in-terim standard of 50 rad. Thus, considering actual enforcement cases to date, application of a 50-tad limit would have been somewhat more effective than the NCRP-recommended emission limit in eliminating notices of vioistions for hot particle overexposures that are considered to be of little biological consequence.
DISCUSSION OF THE INTERIM STANDARD The interim standard provides that, for a single hot particle exposure of an individual, the NRC will enforce a limit on dose to the skin of 50 rad averaged over I cm2 at a depth of 7 mg/cm2 Notices of violation will not be issued for 7
- + - -
+---m
-+
a single hot particle exposure below this limit.
The 50 tad value is more ap-propriate than existing limits of 7.5 and 18.75 rem / quarter for hot particle Some exposureb of skin that are considered to be of little or no consequence.
reduction in the f requency of monitoring of workers for hot particle contami-nation and cortsequent reduction in related'whole-body exposures is expected to result from implementation of this standard.
The 50-rad value also is below the level at which observable non-stochastic effects other than possibly a point erythema" (e.g., changes in pigmentation, desquamation, scarring, ulcera-tion) are expected to result from the exposure and is at a level at whfch the risk of skin cancer from the exposure is very small. Thus the staff believes that the 50-rad value will provide an adequate level of protection for public health and safety for occupational exposures of skin resulting from hot parti-cles.
An even less restrictive standard for a hot particle in contact with the skin, such as that recommended by the NCRP in its draft Report No. 101, may also provide an adequate level of protection; however, as discussed previously, the NRC believes that public comments should be solicited before such a stan-dard is implemented.
The NRC recognizes that the 50-tad interim limit is comparable to the 50-rem annual dose equivalent limit which is recommended in ICRP Publication 26 and NCRP Report 91 for avoidance of non-stochastic effects and which is included in the proposed major revision of 10 CFR Part 20.
However, the 50-tad limit in this interim standard is not an annual limit; it is a limit for a single hot particle exposure of the skin of an individual.
In addition to the 50-tad limit, the interim standard includes criteria the staff will use in evaluating licensees' practices related to records, reports, and notifications for occupational exposures resulting from a hot particle on the body or on clothing.
The level for recording exposures, in accordance with 10 CFR 20.401(a), has been set at 10 percent or more of the 50-rad limit, a level which is consistent with the instructions for Form NRC 5.
The interim standard also includes examples for determining the severity level for violations that involve occupational exposures of the skin in excess of the applicable limit.
These examples are interim additions to 10 CFR Part 2, Appendix C, Supplement IV-Severity Categories, " Health Physics 10 CFR Part 20,"
8 l
w w---.,
- ~ - - - - - - - - - - -
w
and are based on qualitative considerations of the significance of hot particle exposures of the skin compared with other exposures.
i This interim standard falls within the definition of backfitting as defined in
+
However, in relaxing the limits on occupational radiation exposure of the skin from hot particles, this interim standard involves rede-fining the level of adequate protection of the public health and safety for occupational exposures that result from hot particles. Therefore, this interim standard falls within the exemption of 10 CFR 50.109(a)(4)(iii) from the provi-sions of 10 CFR 50.109(a)(2) and (a)(3). These latter provisions require a l
systematic and documented analysis, which is described in 10 CFR 50.109(c),
leading to a determination that there is a substantial increase in the overall public health and safety or common defense and security to be derived from the backfit and that the direct and indirect costs of implementation for the backfit are justified in view of the increased protection.
As was made clear in the statement of considerations for revising the backfitting rule
}'
(53 FR 20603; June 6, 1988), the Commission will not and cannot take economic costs into consideration in defining or redefining what level of protection for the public health and safety or common defense and security should be regarded as adequate.
l i
-Finally, the NRC staff does not intend that the implementation of this interim standard will result in a decrease in radiation protection of workers or the general public or in a decrease in the controls needed to contain hot particles within each plant and prevent them from being transported offsite.
Steven A. Varga Acting Associate Director for Projects Office of Nuclear Reactor Regulation 9
4 1
t J
ENCLOSURE l
.M'
' t Interin Standard t
f on Occupational Dose b
for Skin from Beta Radiation Emitted from a Hot Particle 1,
Purpose i
The purpose of this interim standard is to identify the criteria the staff will use in implementing enforcement discretion that invoWes occupational
[
doses to skin resulting from exposure to radiation emitted from a hot particle on or near the skin. The provisions of this interim standard will be followed by the NRC Otaff until a new limit for this purpose is l
established by revising of 10 CFR Part 20 or by revising this interim standard.
2.
Scope This interim standard applies only to occupational doses to the skin that are the result of radiation emitted from a hot particio on the body or clothing of the exposed individual.
3.
Definitions As used in this interim standard --
" Hot particle" means a discrete radioactive fragment.
" Hot particle exposure" means an occupational dose to the skin resulting from exposure to radiation emitted from the radionuclides in a hot particle on the body or clothing of the exposed individual.
" Occupational dose" includes exposure of an individual to radiation (i) in a restricted area; or (ii) in the course of employment in which the indi-vidual's duties involve exposure to radiation, provided, that "occupa-4
+-...
y.-
re
tional dose" shall. not be deemed to include any exposure of an individual to radiation for the purpose of medical diagnosis or medical therapy of such individual.
(Note: This is the definition of this term given in 10 CFR Part 20).
4.
Occupational Exposure Limit I
The limits on occupational dose specified in the table in paragraph (a) of 10 CFR 20.101 for the hands and forearms, feet and ankles, and the skin of the whole body apply to hot particle exposures. However, because of the nature of the principal radiation (beta) involved, the extremely localized f
effects, and the lower biological risk, the staff believes a different limit should be applied in the interin until a new limit for hot particles-is established by rule.
For a single hot particle exposure of an individual, the Commission will enforce a limit on dose to the skin of 50 rad at a depth of 7 mg/cm2 averaged over an area of I cm2, including the region of highest dose.
A notice of violation will not be issued for,
a single hot particle exposure below this limit.
However, a notice of violation may be issued for additional violations associated with potential hot particle exposures (e.g., violation of 10 CFR 20.201, i
" Surveys") regardless of the exposure level, i
5.
Record Reouirements i
Radiation exposure of individuals.
The staff will consider that the requirements of 10 CFR 20.401(a) for maintaining records of exposures of individuals are adequately met for hot particle exposures if the record includes the following information for an exposure that results in a dose to the skin exceeding 5 rad:
j (a) The specific location of the particle on the skin, hair, or clothing; and b
i 2
4 e-.
e
.e.+_w,__,1, e,_
_ _ _,,.gw wm+y--y-.-+
--y w m
2 ;
i j
I (b) - The activity. of radionuclides in the particle, the duration of.
exposure of the skin, the dose to the skin (rad) at,7 og/ cat j
averaged over 1 cet, and the method used to detemine these values.
4 1
6.
Notifica'tions of Incidents-i The staff will-casider that the notification requirements of y
i 10 CFR 20.403 are adequately met for hot particle exposures if --
(a) for 10 CFR 20.403(a)(1), a value for dose to the skin of 2000 rad or-i more is used as a reporting criterion; and j
(b) for 10 CFR 20.403(b)(1), a value for dose to the skin of 200 rad is used as a reporting criterion.
.7.
Reports of Hot Particle Overexposures The staff will consider that the provisions of 20.405(a)(1)(1) are adequately met for hot particle exposures if reports are submitted for j
ll exposures resulting in doses to the skin exceeding 50 rad.
8.
Personnel Monitorina Reports i
Because the provisions of 10 CFR 20.407 apply to reports of whole-body exposures (and not skin exposures), this section of the regulations is not t
l applicable to hot particle exposures of skin.
y 9.
Reports of Personnel Monitoring on Termination of Employment or Work i
The staff expects reports of hot particle exposures to be included in the reports required by 10 CFR 20.408, using information recorded in accordance with Section 5, " Recording Requirements," of this interim standard.
l 10.
Notifications and Reports to Individuals i
3
i 4 f-O The staff will consider that the provisions of 10 CFR 19.13 and 10 CFR 20.409 are adequately met for hot particle exposures if these notifications and reports to individuals include information recorded in accordance with Section 5. " Recording Requirements," of this interim standard.
11.
Enforcement Examples:
10 CFR Part 2, Appendix C, Supplement IV For hot particle exposures, the staff will use the following values for beta dose to the skin:
(a) Severity Level 1 - Violations involving, for example --
hot particle exposures for which the dose to the skin exceeds 2500 rad.
(b) uverity Level II - Violations involving, for example --
hot particle exposures for which the dose to the skin exceeds 500 rad.
(c) Severity Level III - Violat' as involving, for example --
hot particle exposures for which the dose to the skin exceeds 100 rad.
(d) Severity Level IV - Violations involving, for example --
hot particle exposures for which the dose to the skin exceeds 50 rad, but exposures that do not constitute Severity Level I, II, or III violations.
12.
Effective Date This interim standard is ef fective immediately.
4
1
,.. - ~'
ENCLOSURE 2
., f CRGR Review Package PROPOSED ACTION:
Issue a generic letter to inform licensees of an interim standard that will be used by the NRC staff in exercising enforcement discre-tion for issues that-involve occupational exposure of the skin to radiation emitted from hot particles..The offact of the interim standard will be to
~
change (increase) existing limits on these exposures.
This change is warranted
'because of the.relatively low risk associated with these hot particle exposures and the additional whole-body exposures that may be resulting from monitoring 1
workers for hot particle contamination to prevent exposures of the skin in excess of the current applicable limits.
L q
CATEG_0_RJ: 2 RESPONSE'TO' REQUIREMENTS FOR CONTENT OF PACKAGE SUBMITTED FOR CRGR REVIEW (Item IV.B. of CRGR Charter, Rev. 4 April 1987) 1.
The proposed generic requirement or staff position as it is proposed to be sent out to licensees.
[
i
.The proposed generic regolatory position is contained in the interim j
standard, which is an enclosure to the proposed generic letter that is 1
included with this package'.
l 11.
Draf t. staff papers or other underlying staff documents supporting the requirements or staff positions.
(A copy of all materials referenced in the document shall be made available upon request to the CRGR staff.
Any committee member may request CRGR staff to obtain a copy of.any referenced material for his or her use.)
The staff position is supported in the draft generic letter, which is included with this package.
m The. staff position with respect to use of a 50-rad limit as a conservative interim value for hot particles is supported by scientific information in L
the following two publications by English investigators:
l J. Wells, " Problems Associated with Localized Skin Exposures,"
British Journal of Radiology, Supplement 19, pp.146-150 (1986).
M. W. Charles, " Skin, Eye, and Testis:
Current Exposure Problems and Recent Advances in Radiobiology," J. Soc. Radiol. Protection 6 (2),
4 pp. 69-81 (1986).
The draft generic letter references these publications.
1 III. Each proposed requirement or staff position shall contain the sponsoring office's position as to whetrer the proposal would increase requirements or staff positions, implement e d sting requirements or staff positions, or would relax or reduce existing requirements or staff positions.
q
]V y,. -
q The'prtpened staff position w:uld relax (increase) existing licits en
~ occupational radiation exposure of skin for the particular case of expo-3 sure to radiation from.a hot particle ~-
1 I V.' - The proposed method of' implementation along with the concurrence (and any
[
comments) of OGC on the method proposed.-
j s
The proposed staff position will be implemented by the NRC staff in the exercise of its enforcement discretion in cases involving occupational radiation exposure of the skin to radiction from a hot particle.
o OGC has no legal objections to the proposed staff position.
a V.
Regulatory analyses' generally conforming to the directives and guidance of' NUREG/BR-0058 and NUREG/CR-3568.
n A' regulatory analysis will be included with a proposed amendment to'10 CFR Part 20 that would provide new limits for exposure of the skin from hot
(
3.
particles.
'The staff has. considered the alternative of taking no action other than the proposed rulemaking.
However, the staff recognizes that it will be at least 2 years until a revision to 10 CFR Part 20 can become effective, and the staff believes that, in the interim until the. proposed revision of 10 CFR 20 becomes effective, it is appropriate for the staff to use an
't interim standard that is less restrictive in exercising enforcement 1
discretion in cases that involve hot particle exposures of skin.
The
_l l
staff believes that this interim standard is needed primarily to utilize a i
radiation protection standard that is more appropriate technically for the-biological risk associated with hot particle exposure of the skin and secondarily to reduce additional whole-body radiation exposures frori sources other than hot particles that may result from the relatively frequent monitoring of workers for hot particle contamination. The Nuclear Management and Resources Council (NUMARC) has provided an estimate that monitoring for hot particle contamination is currently costing industry a total of about 20 person-rem per month whole-body dose for the 22 utilities that responded to a. survey, and NU9RC has stated that this cost could be decreased by 10 percent to 25 percent if the interim standard of 75 microcurie-hours recommended in draft Natitnal Council on 4
Radiation Protection and Measurements _(NCRP) Report No. 101 was adopted
~
(letter from T. E. Tipton to T. T. Martin, August 1, 1988, and letter from T.' E. Tipton to T. E. Murley, February 10,.1988).
The 22 utilities represented 47 units and the savings in dose expected by NUMARC if a 75 microcurie-hour limit was adopted is'0.6 to 1.5 person-rems per year per unit.
This savings may'be ccmpared to the industry light-water reactor average of 420 person-rem per unit in 1987.
The savings resulting from the 50-rad limit are not expected to exceed the savings from the 75 microcurie-hour limit.
This interim standard f alls within the definition cf backfitting as defined in 10 CFR 50.109(a)(1).
However, in relaxing limits on occupa-tional radiation exposure of skin from hot particles, this interim stan-dard involves redefining the level of adequate protection of the public health and safety.
Therefore, this interim standard falls within the 2
'i.
oxopptien of 10 CFR 50.109(a)(4)(iii) from the pr visions of 10 CFR 50.109(a)(2) and (a)(3).
These latter provisions require a systea-atic and documented analysis, described in 10 CFR 50.109(c), leading to a determination that there is a substantial increase in the overall public health and safety or common defense and security to be derived from the backfit and that the direct and indirect costs of implementation for the backfit are justified in view of the increased protection.
As was made clear in the statement of considerations for revising of the backfitting rule (53 FR 20603; June 6,1988), the Commission will not and cannot take economic costs into consideration in defining or redefining what level of protection for the public health and safety or common defense and security should be regarded as adequate.
VI.
Identification of the category of reactor plants to which the generic requirements or staff position is to apply (that is, whether it is to apply to new plants only, new OLs only, OLs af ter a certain date, OLs before a certain date, all OLs, all plants under construction, all plants, all water reactors, all PWRs only, some vendor types, some vintage types such as BWR 6 and 4 jet pump and nonjet pump plants, etc.).
This staff position applies to all NRC licensees (both reactor and material licensees); however, the additioral whole-body exposures that are being received because of increased monitoring programs are mainly at power reactor facilities.
The generic letter is being sent only to reactor licensees.
(NMSS may send a generic communication on this subject to its licensees sometime later.)
VII. For each such category of reactor plants, an evaluation which demonstrates how the action should be prioritized and scheduled in light of other ongoing regulatory activities.
The evaluation shall document for consid-eration information available concerning any of the following factors as may be appropriate and any other information relevant and material to the proposed action:
i (a) Statement of the specific objectives that the proposed action is designed to achieve; The proposed actior. 3 designed to change (increase) existing limits on occupational radiation exposure of skin and thereby to utilize radiation protection criteria that are more appropriate to the biological risk associated with hot particle exposures of skin.
A secondary objective is to reduce whole-body occupational radiation exposure from sources other than hot particles that is associated with monitoring of workers for hot particle contamination.
(b) General description of the activity that would be required by the licensee or applicant in order to complete the action; Not applicable.
The proposed action will be taken by the NRC staff.
Although it is not required, the staff expects, however, that some licensees will voluntarily reduce the frequency of monitoring workers for hot particle contamination and, thereby, reduce whole-body exposures from other sources.
3
(*
1 a*
. (c)l Potential change in:the risk to the public-from the accidental Q+
.offsite release of radioactive material;:
y 4
For members of the general'public'(i.e., those who are not occupa-4 tionally exposed),!the staff. expects;that the proposed action will
(
not result in any change in risk.
(d) Potential impact on radiological exposure of facility employees and other onsite workers.
For members of the public who are' occupationally exposed, the staff expects that the proposed. action (1) will; not result in any signifi-cant increase in the risk resulting from hot particle exposures of 4
skin' and (2) will result in a slightly decreased risk from whole-body exposures to radiation from sources other than hot particles..
u p
(e) Installation-and continuing costs associated with the action, includ-
.ing the cost.cf facility downtime or the cost of construction delay; Not applicable.
(f) The potential safety impact of changes in plant or operational complexity, including the relationship to proposed and existing.
i 1
regulatory requirements and staff positions; 1
.Not applicable.
There are no " changes in plant or operational complexity" associated with the proposed action.
(g) The estimated resource burden on the NRC associated with-the proposed
.j L
action'and the availability of such resources; There is virtually no resource burden on the NRC associated with the proposed action.
(h) The potential impact of differences in facility type, design or age J
on the relevancy-and practicality of the proposed action; No impact.
(i) Whether the proposed action is interim or final, and if interim, the justification for imposing the proposed action on an interim basis.
Interim.
See response to item V above for justification.
'VIII.
For each evaluation conducted pursuant to 10 CFR 50.109, the proposing J
office director's determination, together with the rationale for the i
determination based on the considerations of the above, that (a) There is a substantial increase in overall protection of public health and safety or the common defense and security to be derived from the proposal; and 1
4
The direct' and indir9ct costs'of implementation fGr the facilities y
i
, i ~ L(b) i 4x' affected are justified in view of_ this increased protection.
As _ noted in the respons( to item V;'although the proposed action is L
backfitting as defined in 10 CFR-50.109(a)(1)', the action is exempt under
~10 CFR 50.109(a)(4)(iii) from the requirements of 10 CFR 50.109(a)(2)'and (a)(3) that require evaluation pursuant to 10 CFR 50.109(c)'because the-proposed action involves redefining the. level of adequate protection of g
l the public health and safety, h
IX.
F'or each evaluation conducted for proposed relaxations or decreases in i
current requirements or staff positions, the proposing office director's i,
determination, together with the rationale for the determination based on.
i the considerations of the above, that (a) The public health and safety and the common defense and security would be adequately protected if the proposed reduction in require-1 ments or positions were implemented, and See response to VII(c). Although the proposed. action, in effect,'
i increases the limits for occupational exposures of skin to beta radiation from hot particles, the proposed action (1)'is not expected to result in any significant change in the risk resulting from hot 7L" particle exposures of skin and (2) is expected to result in a slightly decreased risk'from whole-body exposures to radiation from L
sources other than hot particles.
For members of the general public L-l (those not occupationally exposed), the proposed action is not 1
expected to result in any. change in risk.
The proposed actbn will h'
have no effect-on the common defense and security. Therefore, the public' health and safety and the common defense and security will be L
adequately protected-if the proposed action is implemented, l
p (b) The cost savings attributed to the action would be substantial enough to justify taking the action, u
1 As noted in the response to item V, the proposed interim standard P
involves redefining what level of, protection for the public health and safety is regarded as adequate, and, therefore, the Commission cannot take economic costs into consideration.
The proposed action is justified because of (1) the qualitative benefit of using a revised radiation protection limit that is based on scientific data that became available af ter the existing' limits in 10 CFR Part 20 were promulgated and that is more appropriate to the biological risk associated with occupational exposures resulting from hot particles and (2) the savings in collective whole-body radiation J
exposures that are expected to result from implementation of the proposed action.
m 5
5 e
f ij
, lo t
-i
. "s' ' L,
?
ENCLOSURE 3.
- 4 L
+
~(Ncgative. Consent' Paper) q s
i For:.
The Commissioners
- 1 From:'
Victor Stello, Jr.
y.
Executive Director for Operations
'i
' Subject-
. INTERIM' STANDARD FOR OCCUPATIONAL EXPOSURE OF THE SKINETO RADIATION FROM SMALL RADI0 ACTIVE PARTICLES'(HOT PARTICLES)
- \\
Purpose:
To_ obtain the Commission's~ approval of an interim standard
[i that will be used by the NRC staff in taking enforcement action for a: violation that involves occupational: exposure of the skin to. radiation emitted from hot particles.
,.1' Discussion:
The enclosed generic letter will be sent to all reactor licensees and applicants.. This letter is to inform-licensees of the-staff's position on enforcement of limits
.i s;
a I
J
= CONTACTS:
John D. Buchanan, NRR 492-1097
.I Jack Bell, RES 492-3747 James Lieberman, OE 492-0741 t.
k
\\
- s
- w
^ - ^
^-
{.
i{f O q;.y
'J g
y 4:
f't' on occupational exposure of the skin to radiation emitted i
from small radioactive particles, commonly known as hot-g particles. :The letter encloses an= interim standard for H
this type of. occupational exposure.
As' defined in this q
y U
letter and the standard, a hot particle means a discrete-1:
radioactive fragment.
,?
q The dose limits of 10 CFR Part 20 for occup9tional exposure
_of.the' skin are 7.5 rem per quarter except for.the skin of
.the hands and forearms and feet and ankles,.for which the limit is.18.75 rem per quarter.
It appears.that these
-.. limits are overly restrictive when applied to exposures 1
.from hot particles.
For the past several years,.the NRC staff has exercise 6 j
discretion in enforcement actions associated with exposures of small areas of the skin in excess of the ' current limits of-10 CFR Part 20 resulting from hot particles.. This has-l O
resulted in the severity levels in the Enforcement Policy-q (Supplement IV to Appendix C of 10 CFR Part 2) for such overexposures being lower than for similar exposure levels where larger skin areas (and volumes of tissue) are exposed to radiation.
(See Statement of Consideration for i
October 13, 1988 revision to the Enforcement Policy, 53 FR 40021.) However, for violations associated'with hot
.l particles, such as failure to do appropriate surveys, the staff has not deviated from the Enforcement Policy.
2
~~
m m~
3 s,.
,,. v -
,v, f
l t
j
{
f,' :
~.The staff, plans.to develop'an amendment:to 10 CFR Part-20 '
q D.:- -
j to prcvide a new: limit for exposure of the skin by hot-f particles.
In the interin until an' amendment to 10 CFR 20-1
- becomes effective, the interim standard will be used by.the -
l t
c staff;in evaluating violations of 10 CFR 20 that involve,
J. '
exposure of the skin to radiation emitted from hot parti--
.A E
l cles. The effect of this change is that licensees will: not.
l be required to meet the more restrictive provisionc~in 1
-10 CFR 20.
Enforcement action will be.taken for violations.
i
'I
^
- involving _ exposures to hot particles.only if:.theiconditions in this generic letter are not met.
However, other viola-!
.i
/
tions.such as failures to do' surveys may result in enforce--
)J F-
<w ment action regardless of the exposure-levels consistent 4
g with current practice.
- .e The interim standard enclosed with the generic letter t
f 9
provides that, for a single hot particlefexposure of.an individual, the NRC will enforce a 1imit on dose to the-
~
s skin of 50 rad averaged over-1 cm2latia. depth of 7 mg/cm2 M
A notice of violation will.not be issued for a' single: hot E
particle exposure of an individual below this limit..
y The rationale for the interim standard is provided in the generic letter.
f
(
3 D
=-. y.
a_
- o
'_'q y,.;,
+
,.J,tRetommendation: L
- The; staff intend's to. issue the enclosed generic letter en.
. me.
- (2' weeks after the daie of this informa '
tion paper), unless the. commission directs otherwise.
y 11 '-
Coordinationi:
- The Oftlee of the' General Counsel has no legal objection to?
7' 4 "
the use of enforcement discretion in this matter provided
,a-prompt rulemaking is undertaten..
r-p Victor'Stello, Jr.
Executive Director
- n
' ~
for Operations
Enclosure:
Generic Letter-
-t hl.
a l
4
!~
r i
h.
I
~
.i 1
I 1'
l-a l '
0 t.
I t
4 L.
(I