ML20206E380

Responds to NRC 870310 Notice of Violation from Insp Rept 50-395/86-22.Corrective Actions:Health Physics Procedure HPP-405, Personnel Decontamination Revised to Include Precautions Re Nonuniform Contamination Events

ML20206E380
Person / Time
Site:	Summer
Issue date:	04/09/1987
From:	Nauman D SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
NUDOCS 8704130594
Download: ML20206E380 (6)

Text

'

Dan A. tmian

, $%Q'gna Electric & Gas Company um 29218 Nuclear Operations SCE&G

~*

April 9, 1987 Dr. J. Nelson Grace Regional Administrator U. S. Nuclear Regulatory Commission Region II, Suite 2900 101 Marietta Street, N.W.

Atlanta, Georgia 20323

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No. NPF-12 Response to Notice of Violation NRC Inspection Report 86-22

Dear Dr. Grace:

On March 10, 1987, the Nuclear Regulatory Commission (Region II) issued a Notice of Violation for alleged violations of NRC requirements at South Carolina Electric & Gas Company's (SCE&G) Virgil C. Summer Nuclear Station.

SCE&G has thoroughly reviewed and investigated the incidents described in the Notice and, pursuant to 10CFR2.201, is responding to the alleged violations in Attachments I and II.

In response to the incidents cited in the Notice, SCE&G has utilized the best available resources to investigate and evaluate the consequences of this inadvertent exposure, with the health and safety of the individual being the highest priority. An exhaustive evaluation of the estimated biological effect was performed and a dose equivalent assigned that most properly and conservatively reflects the stochastic and non-stochastic effects of this exposure. The calculational methodology used in determining the biological impact is not at variance with the existing regulations in 10CFR20 and is currently considered by recognized experts to be the most technically accurate approach to analyzing the effects of a highly localized exposure.

Given the lack of any specific methodology for these circumstances in the existing regulations, use by SCE&G of the most current technology for dose assessment of not particle contamination, and the prompt revision of existing procedures tJ allow assessment of dose due to hot particle skin contaminatior, a reduction of the Severity Level of this event is requested.

SCE&G i- committed to a stringent radiological protection program as evidencu by prior performance in Health Physics and the approach taken in this matter. The corrective actions taken and improvements made represent the level of management attention given to this matter in an effort to maximize the quality of the program. It is very important that differences between the industry consensus approach and NRC guidance regarding hot particle dose assessment be resolved in an expeditious manner. Without resolution, these differences will continue to generate unrealistic dose assignments and unnecessary enforcement activity.

pel 8704130594 R70409 ( f PDR ADOCK 0C000395 G PDR L

Dr. J. N]1 son Grace April 9, 1987 Page 2 The undersigned affirms that the statements and matters set forth in this letter and its attachments are true and correct to the best of my knowledge, information, and belief.

Very t ul ours, 1

1 6

i . u an AMP / DAN:jez Attachments c: 0. W. Dixon, Jr./T. C. Nichols, Jr.

E. C. Roberts

0. S. Bradham J. G. Connelly, Jr.

D. R. Moore W. A. Williams, Jr.

Group Managers W. R. Baehr C. A. Price W. T. Frady C. L. Ligon (NSRC)

R. M. Campbell, Jr.

K. E. Nodland R. A. Stough G. O. Percival R. L. Prevatte J. B. Knotts, Jr.

I&E Washington NPCF File

Attachment I to Dr. J. N31stn Grace Latter April 9, 1987 Page 1 of 2 Response to Notice of Violation Violation No. 50-395/86-22-01 I. ADMISSION OR DENIAL OF THE ALLEGE 0 VIOLATION South Carolina Electric & Gas Company is in partial agreement with the alleged violation.

II. REASON FOR THE VIOLATION South Carolina Electric & Gas Company did not have a procedure which adequately addressed calculations for skin exposures due to highly localized, hot particle, skin contamination. Such hot particle 4 contamination results in a significant under response of monitoring devices in comparison to contamination of a more uniform distribution.

Procedural requirements which address hot particle contamination had not been developed because no evidence of such contamination previously existed at the Virgil C. Summer Nuclear Station. However, procedures were in place which are adequate to address skin contaminations which are more uniformly distributed.

Procedural requirements for notification of management of significant contamination events were also in place. The delayed notification of management in this incident was due in part to the lack of specific procedural direction for hot particle contamination and personnel errors in recording the results of surveys taken.

III. CORRECTIVE ACTION TAKEN AND RESULTS ACHIEVED The corrective actions taken in responses to the procedural aspects of this incident inciude the following:

Health Physics Procedure HPP-405, " Personnel Decontamination," was revised on February 6,1987 to include precautions pertaining to non-uniform (hot particle) contamination events. Methods for determining the source distribution as well as appropriately conservative correction factors for point source geometrics for the RM-14/HP-210 and R0-2 survey instruments have been included in the revised procedure.

All health physics technicians have received additional training in handling skin contamination events including the determination of source distributions and the methods of estimating dose to the area of skin contaminated.

-m._ _.-_...__.._,7 , __y _m ,._m_y.,,,7._-_ , _ . , , . - . _ _ . - , -

_, ,,.,y_ . . . _ . . - . _ _ _ - ,

Attachment I to Dr. J. Nelson Graca Letter April 9, 1987 Page 2 of 2 IV. CORRECTIVE ACTION TAKEN TO AVOID FURTHER VIOLATION The Corporate and plant health physics groups will continue to assimilate information partaining to skin contamination dose assessment and will modify appropriate procedures as necessary to reflect industry best practices.

V. DATE OF FULL COMPLIANCE Full compliance was achieved upon approval of Revision 4 to HPP-405 on February 6, 1987.

L i .

i Attachment II to Dr. J. Nelson Graca Letter April 9, 1987 Page 1 of 2 l

Response to Notice of Violation Violation No. 50-395/86-22-02

1. ADMISSION OR DENIAL OF THE ALLEGED VIOLATION South Carolina Electric & Gas Company denies the alleged violation.

II. REASON FOR DENIAL OF THE VIOLATION The subject Regulation (10CFR20.101(a)) states that "no licensee shall possess, use, or transfer licensed material in such a manner as to cause any individual in a restricted area to receive in ary period of one calendar quarter from radioactive material and other sources of radiation a total occupational dose in excess of..18.75 rems per calendar quarter to the hands and forearms; feet and ankles (extremities)." Demonstration of compliance with 10CFR20.101(a) requires licensees to adequately assess the occupational dose and maintain records pursuant to 10CFR20.401. SCE&G contends that the dose to the individual in question was adequately assessed and appropriately recorded pursuant to 10CFR20.401 as 0.43 rem (LER 86-018 Rev. 1). Thus, the recorded exposure does not represent a violation of 10CFR20.101(a).

SCE&G understands the Staff position that NRC regulations are currently based on the recommendations of NBS Handbook 59; however, significant advancements in the field of Health Physics have been achieved since the publication of Handbook 59 in 1954. Most notable of these advancerrents was the publication of Report 26 by the International Conmission on Radiation Protection in 1977.

Recommendatiors contained within Report 26 have subsequently been endorsed by the intenurtional radiation protection community as well as proposed for ir. corporation into Federal Regulations (Federal Register, January 9, 1986, page 1092, Vol. 51, No. 6). The Commission stated that the intent of the proposed revision to 10CFR20 is to improve NRC radiation protection standards by reflecting developments in the principles that underlie radiation protection and advances in related sciences that have occurred since the promulgation of 10CFR20 thirty years ago. Report 26 recommends a system of dose limitations which requires assessment of dose equivalent proportional to the risk l of adverse health effects to the individual, either for medically discernable (non-stochastic) damage in the short term or the risk of cancer (stochastic) in the long term. Furthermore, this concept is codified in 10CFR20.4(c): "The Rem as used in this part, is a measure of the dose of any ionizing radiation to body tissues in terms of its estimated biological effect relative to a dose of one roentgen (r) of

3 Attachment II to Dr. J. Nelson Graca Letter April 9, 1987 Page 2 of 2 X rays. The relation of the Rem to other dose units depends upon the biological effect under consideration and upon the conditions of irradiation." Therefore, by regulation, dose-equivalent must be proportional to biological risk.

Guidance for calculating skin dose provided by the Staff in IEN 86-23 and instructions contained on Form NRC-5 represent methodologies which are acceptable to the Staff for the purpose of demonstrating compliance with 10CFR20. However, this guidance does not represent the only acceptable or most appropriate method for demonstrating compliance with federal regulations. An industry survey made as part of actions taken in response to this incident clearly indicates a wide variability in methodologies utilized in this area.

The fraction of cells irradiated by a hot particle is an infinitesimal fraction of the whole body with the majority of these cells being destroyed by the high doses within the range of the beta particles.

Therefore any real " dose-equivalent" from the beta component is vanishingly small and implementation of IEN 86-23 guidance would, contrary to the regulation, not only overestimate the risk, but would also give, in later years, a basis for an inaccurate probability of causation for any cancer the person might develop. For this reason, SCE&G considers IEN 86-23 guidance inappropriate for determining dose equivalent due to hot particle contamination.

With the foregoing discussion in mind, SCE&G has performed a dose assessment which incorporates the philosophy of ICRP 26 and has assigned, as required by 10CFR20.4(c), a dose-equivalent which is proportional to the biological risk incurred by the individual. That dose equivalent is 0.43 rem and represents an estimate of the risk for stochastic effects proportional to the number of basal cells which received a radiation dose and survived (dose equivalent due to gamma rays averaged over 100 square centimeters).

The dose equivalent of 0.43 rem to an extremity does not represent a violation of 10CFR20.101(a).

. . -- - - _ _ . _ __