ML20236X776
| ML20236X776 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 12/03/1987 |
| From: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Nauman D SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| EA-87-007, EA-87-7, NUDOCS 8712100258 | |
| Download: ML20236X776 (7) | |
See also: IR 05000395/1986022
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DEC 0 31987
Docket No.: 50-395
License No.: NPF-12
EA 87-07
South Carolina Electric and Gas Company
ATTN: Mr. D. A. Nauman, Vice President
Nuclear Operations
P. O. Box 764 (167)
Columbia, SC 29218
Gentlemen:
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SUBJECT:
NRC INSPECTION REPORT NO. 50-395/86-22
Our letter dated July 13, 1987, in response to your letter of April 9,1987,
stated that with regard to violation A, we concluded for the reasons presented
in the Enclosure to our letter, the violction occurred as stated in the Notice
of V M ation (NOV) transmitted with NRC Inspection Report No. 50-395/86-22.
With regard to your letter of August 7,1987, after careful review of the bases
for your denial, we continue to conclude, for the reasons presented in the
Enclosure to this letter, that the violation occurrer: as stated in the NOV.
We
again have also considered your view that the proposed severity level for both
violations is not warranted and again concluded that the violations were
appropriately categorized as a Severity Level III problem.
Since you provided corrsctive actions for the violation durira the Enforcement
Conference held on December 16, 1986, as documented in NRC Inspection Report
No. 50-395/86-22 sent to you on March 12, 1987, no further response is
requi red.
If your understanding of corrective actions has changed since this
meeting, you should provide the NRC an update of the corrective actions.
The NRC recognizes that the calculated dose of 420 rems is a quite conservative
value and that the safety implications of the dose may be significantly reduced
because of the extremely limited area of exposure.
Because of the lessened
safety significance of this dose, as opposed to a similar dose to a large area
of skin, the NRC categorized the violation as a Severity Level III rather than
a Severity Level I, which is that listed in our Enforcement Policy in
10 CFR Part 2 for skin doses in excess of 375 rems.
We recognize the unique
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circumstances of high doses to very small areas of the skin. We also agree
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with your consultant's recommendation that the individual's cose record should
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contain a notation of the circumstances of this dose to put the dose in proper
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South Carolina Electric
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DEC 0 31987
and Gas Company
As we have indicated previously, the NRC recognizes the general need for a
reevaluation of the basis for dose assignment due to very small, highly
radioactive particles on the skin. The NRC formally requested the National
Council on Radiation Protection and Measurements to review and provide guidance
on the issue. We will keep you informed of any changes to our regulations and
criteria that may result from this review.
In the interim, and unless there
are changes forthcoming, however, the agency will continue to' assess skin
exposures in accordance with the existing policy.
In accordance with Section .2.790 of the NRC's " Rules of Practice," Part 2,
Title 10, Code of Federal Regulations, a copy of this letter and its enclosure
will be placed in the NRC Public Document Room.
We appreciate your cooperation in this matter.
Sincerely,
OF3GRiAL W !E0 U"
lie 1SDilCR!,
J. Nelson Grace
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Regional Administrator
Enclosure:
Staff Assessment of Licensee
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Response to Notice of Violation with
Attachment
cc w/ encl:
0. S. Bradham, Director, Nuclear Plant
Operations
J. L. Skolds, Deputy Director
Operations and Maintenance
J. B. Knotts, Jr.
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Debevoise and Liberman
W. A. Williams, Jr., Special
Assistant, Nuclear Operations -
Santee Cooper
A. M. Paglia, Jr., Manager
Nuclear Licensing
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DEC O 31987
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OEC 0 31987
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ENCLOSURE
STAFF ASSESSMENT OF LICENSEE RESPONSE TO
Violation A (50-395/86-22-02) involved the failure to control licensed material
in such a manner as to limit the occupational dose to an individual's
extremities to less than 18.75 rems per calendar quarter as required by
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Licensee Comment:
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10 CFR Part 20 does not prescribe a method of calculating non-uniform doses
resulting from a " hot particle" on the skin of an extremity, and NRC IEN 86-23
is not a regulatory requirement which can be made the basis for a Notice of
Violation.
NRC Response:
As stated previously in the Enclosure to our letter dated July 13, 1987, NRC
regulations are based on recommendations such as those in ICRP 26, Radiation
Protection Guidances to Federal Agencies (developed by EPA), NBS handbooks,
current research by recognized experts, and comments received during the public
comment period for proposed rule changes. The current 10 CFR Part 20 is based,
in substantial part, on the recommendations of NBS Handbook 59. Where there is
a need to clarify the intent of NRC regulations, the preferred approach is to
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obtain clarification from the base document, in this case NBS 59. Thus in this
case, where specific implementation details on how to do assessments are not
included in 10 CFR Part 20, the source documents were used to define the methods
used.
With regard to IEN 86-23, it should be noted that the main purpose of this
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Notice was to inform licensees of occurrences of skin contamination by small
particles of radioactivity.
Licensees were expected to review the information
in the Notice for applicability to their specific program.
In addition, the
Notice reminded licensees of the long-standing NRC policy regarding assessments
of dose to the skin. The Notice did not create a regulatory requirement; it
did provide information on events and remind licensees of techniques for skin
dose calculation.
The NRC recognizes that significant advances have been achieveo in the field of
Health Physics as noted in your response. The proposed 10 CFR Part 20 has been
out for comment, and comments received are being reviewed. The general points
made by SCE&G and those provided by other sources regarding the advancements in
health physics will be considered during the review.
Nonetheless, the current
regulations remain valid and in effect.
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DEC 0 31987
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Licensee Comment:
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Calculational methods consistent.with current good practice in the field of
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health physics, such as the method employed by SCE&G, should be accepted'in the
absence of a method prescribed, or incorporated by reference, in the
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regulations.
The thirty year old method on which NRC guidance and regulatory interpretation
is based (NBS Handbook No. 59) results in significant over estimation of
biolcgical effects of such an exoosure which is inconsistent with the
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philosophy of current recommendations, such as International Commission on
Radiological Protection (ICRP) Publication 26 and the principles of ALARA.
Based on recommendations of the ICRP and previous guidance provided by the NRC,
SCE&G contends that guidance given in IEN 86-23 is inappropriate for
determining dose equivalent due to hot particle contamination.
Furthermore,
ICRP-26 states in Paragraph 183, "... if the dose . distribution is extremely
non-uniform, as that from very small particles in contact with the skin, the
local absorbed dose (rads due to beta and gamma components) should be assessed
and used to predict possible local skin reactions." SCE&G implemented this
recommendation to determine the potential for non-stochastic effects (cosmetic
changes) and retained professional medical assistance to assure there were no
local skin reactions.
The ICRP goes on to say that "It is inappropriate,
however, to relate such localized absorbed doses to the absorbed doses
corresponding to the dose-equivalent limit." Regulatory interpretation as
reflected in IEN 86-23 contradicts previous staff guidance, Regulatory
Guide 8.23, while ignoring both current state-of-the-art and ICRP recommenda-
tions.
NRC Response:
NRC recognizes the need for a reevaluation of the basis for dose assignment due
to very small, highly radioactive particles.
Recently the NRC formally
requested the National Council on Radiation Protection and Measurements (NCRP)
to review and provide guidance on this issue.
As appropriate, when this
guidance is received, the NRC will re-evaluate the current basis of
10 CFR 20.101(a). However, until, and unless, the basis of 10 CFR 20.101(a) is
changed, the guidance in NBS Handbook 59 and IE Notice 86-23 is to be used in
determining compliance with the current regulations.
IEN 86-23, rather than
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being contrary to the regulations, as you indicated, represents the NRC
position on how licensees should calculate the dose to the skin from
radioactive contamination.
This guidance is considered most appropriate at
this time.
It is not at all clear, as suggested by SCE&G, that the basis of
10 CFR 20.101(a) should be changed.
Recent scientific publications (see
Attachment) have indicated that the ICRP-26 guidance is inadequate,
particularly for non-uniform exposures, and have suggested the continued use,
as an interim measure, of the current practice of determining skin dose at the
basal layer of the epidermis (7 mg/cm2) averaged over an area of one square
centimeter.
Licensee Comment:
Regulatory Guide 8.23 (in a footnote to Table 2) states that for the hands,
averaging over the whole area of the hands is acceptable, nominally 300 cm2,
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DEC 0 31987
NRC Response:
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The NRC had noted the need for a change in this portion of Regulatory
Guide 8.23 since it implied a method of calculation different from that upon
which the regulations were based.
Action has been initiated to revise this
Regulatory Guide to make it clearly consistent with NRC policy.
Licensee Comment:
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ICRP-26 does not, as pointed out by your response, support the omission of the
beta component; however, paragraph 17 states that the absorbed dose is
insufficient by itself to predict either the severity (non-stochastic) or the
probability (stochastic) of the deleterious effects on health resulting from
irradiation under unspecified conditions. The dose equivalent unit, rem, was
developed to correlate delayed stochastic effects with radiation exposure.
SCE&G has therefore assigned a dose equivalent which more appropriately
correlates the probability of future stochastic effects due to the skin
irradiation by this highly localized contamination.
That dose equivalent which
reflects current understanding of the 1.tochastic risks associated with skin
dose, has been recorded as 0.43 rem and does not exceed the limits of
NRC Response:
As stated in our letter of March 10, 1987, it is the NRC's position that the
methodology SCE&G used was inappropriate. The beta component cannot be
ignored, nor is it appropriate to average the dose over 100 cm2
Furthermore,
ICRP-26 does not suggest that the dose from the accidental contamination of
individuals from small particles should be averaged over any area larger than
one square centimeter. As stated above, the NRC does have under evaluation
consideration of changes in skin dose assessment methodology that might result
in a different factor for converison from a rad to a rem for doses to very small
areas of the skin. Until a decision is made on whether such a change is appro-
priate,10 CFR Part 20 specifies that for beta doses, one rad equals one rem.
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DEC 0 31987
ATTACHMENT
NUREG/CR-4418, " Dose Calculation for Contamination of the Skin
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Using the Computer Code VARSKIN," PNL 5610, August 1987.
Reece, W.
D., et al., " Extremity Monitoring: Considerations for
Use, Dosimeter Placement and Evaluation," NUREG/CR-4297,
December 1985.
Charles, M. W. and J. Wells, "The Development of Criteria for
Limiting the Non-Stochastic Effects of Non-Uniform Skin Exposure,"
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Proceedings of the 5th Congress of the International Radiation
Protection Society, Jerusalem, March 1980.
Rohlof, F. and M. Heinzelmann, " Calculation of Dose Rates for Skin
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Contamination by Beta Radiation," Radiation Protection
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Dosimetry 14 (4), 279-287 (1986).
Strather, J. W., " Radiation Damage to Skin," Report of a Workshop
on Radiation Damage to Skin, Fundamental and Practical Aspects,
Saclay, France, 9-11 October, 1985, NRPB Bulletin, No. 70,
(March 1986).
Francis, T. M. , " Dosimetry of Beta Particles and Low-Energy
X-Rays" Report of a Workshop held at the Nuclear Research Centre
(March 1986)y, France, 7-9 October, 1985, NRPB Bulletin, No. 70,
(CEA),Sacla
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Charles, M. W. , " Skin, Eye, and Testis:
Current Exposure Problems
and Recent Advances in Radiobiology," J. Soc. Radiol. Prot. 6, (2),
69-81 (1986).
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