ML20210J886

Provides Clarification to Commitment Made in Identifying Extent by Which Existing Plant Design Complied with RG 1.97,specifically Re Variable, Radiation Exposure Rate

ML20210J886
Person / Time
Site:	North Anna
Issue date:	08/02/1999
From:	Christian D VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-REGGD-01.097 99-396, NUDOCS 9908050131
Download: ML20210J886 (3)

Text

T Vuu;isir Ei.ecTRIC AN9 POWER Cmtl%NY l

RICHMONI), VHM; INIA 232fil l

August 2, 1999 U.S. Nuclear Regulatory Commission Serial No.99-396 Attention: Document Control Desk NL&OSvihR1 Washington, D.C. 20555 Docket Nos. 50-338 50-339 License Nos. NPF-4 i NPF-7 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 REGULATORY GUIDE 1.97, ACCIDENT MONITORING INSTRUMENTS CLARIFICATION OF COMMITMENT in a letter dated January 31,1984 (Serial No. 054) Virginia Electric and Power Company (Virginia Power) identified the extent by which the existing plant design l complied with Regulatory Guide 1.97. The NRC reviewed the submittal as the basis of i Virginia Power's commitment to Regulatory Guide 1.97. That review is documented in a NRC letter dated February 8,1985. This letter provides a clarification to that commitment, specifically regarding the variable, " Radiation Exposure Rate".

l l In our January 31,1984 letter, Virginia Power identified this variable as both a Type C and Type E variable. However, Revision 3 to Regulatory Guide 1.97 deleted the variable as a Type C indication based on the conclusion, "... that the function... could be just as effectively performed by the effluent monitors installed at release points from those buildings. Therefore, the exposure rate monitors inside buildings for the purpose 9 of detecting containment breach were deleted from the guide..." Consistent with the NRC review, which was performed based on Revision 3 of the Guide, Virginia Power is clarifying its commitment to Regulatory Guide 1.97 by formally deleting " Radiation Exposure Rate" as a Type C variable.

In addition, a recent evaluation of accident monitoring instrumentation identified that the range of the existing area radiation monitors designated as addressing the Type E variable, " Radiation Exposere Rate", was different than the range specified in Regulatory Guide 1.97. Specifically, these monitors cover a range from 10" mr/hr to

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,.10' mr/hr in lieu of 10 R/hr to 104 R/hr. In our January 31,1984, letter on Regulatory Guide 1.97, we did not identify any exceptions to the Guide for this variable.

I This Type E variable is identified in Regulatory Guide 1.97 as applying to "inside buildings or areas where access is required to service equipment important to safety" with a purpose of " detecting significant releases; release assessment; long term surveillance". For those areas where access is " required to service equipment important to safety", fixed area monitors are provided in conjunction with portable radiation monitoring instrumentation. The portable monitoring instrumentation is a separately provided Type E variable, " Plant and Environs Radiatbn", with an instrument range of 10-2 R/hr to 2 X104R/nr.

Most of the range specified by Regulatory Guide 1.97 for the fixed-location, Type E monitor is above radiation levels considered acceptable for human entry. The upper portion of the specified range (10' to 104 R/hr) is considered lethal. Unrestricted entry is precluded at North Anna for areas with radiation levels above 10 mr/hr or for fixed area monitors that are reading off-scale. Subsequent entry into such areas is controlled procedurally for radiation protection considerations.

Estimating dose for subsequent entry or an emergency exposure authorization requires l either use of an on-scale area radiation monitor or survey data as specified by l Emergency Plan Implementing Procedures (EPIPs). Subsequent monitoring of areas I with elevated radiation levels "where access is required to service equipment important  ;

to safety" will be conducted with portable monitoring equipment, consistent with Health l Physics practices and procedures.  ;

EPIP 4.14 requires that if the dose rate exceeds 103 mr/hr that the monitoring consist of a team of at least two individuals, one of which is a Health Physics technician with a portable survey meter. Furthermore, if the TEDE dose is greater than 5 Rem, HP coverage is required along with instrumentation capable of reading radiation levels up to 10' R/hr. EPIP 4.14 requires the range of the instrumentation be capable of measuring anH::ipated levels in accordance with Health Physics procedures.

Based on existing Health Physics practices and procedures, the Type E variable function for " Radiation Exposure Rate" to monitor areas "where access is required to service equipment important to safety", is accomplished by an integrated approach of fixed and portable equipment with ranges consistent with radiation protection practices.

Accordingly, Virginia Power clarifies and changes its commitment for this variable to correct the designated range of the associated fixed instrumentation to 10' to 10 mr/hr.

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. If you have any further questions, please contact us.

Very truly yours,

) b-David A. Christian I Vice President - Nuclear Operations Attachment Commitments made in this letter:

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1. Formal deletion of " Radiation Exposure Rate" as a Regulatory Guide 1.97 Type C variable. l

2. Correction of designated range commitment for Regulatory Guide 1.97 Type E 4

variable, " Radiation Exposure Rate", from 10 ' to 10 R/hr to 10-'- 10 mr/hr.

cc: U.S. Nuclear Regulatory Commission Region ll Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303 Mr. M. J. Morgan NRC Senior Resident inspector North Anna Power Station L