ML20105D058

Requests Extension Until 831007 for Completion of Outlined Action Plan Re Resolution of Discrepancy Between Beta Radiation Dose Measurements Made W/Portable Survey Instruments & W/Tlds,Per CAL-280/83-01 & CAL-281/83-01

ML20105D058
Person / Time
Site:	Surry, 05000000
Issue date:	07/01/1983
From:	Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20105C697	List: ML20105C946 ML20105D058 ML20105D110 ML20105D144 ML20105D178 ML20105D243
References
FOIA-84-574 242A, CAL-280-83-01, CAL-280-83-1, CAL-281-83-01, CAL-281-83-1, NUDOCS 8502090582
Download: ML20105D058 (2)

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Vart Patanpew7 wmea or .mo . July 1, 1983 .

Mr. James P. O'heilly Serial No. 242A Regional Administrator N0/WDC:aca ReFi on II Docket Nos. 50-280 U. S. Nuclear Regulatory Commission 50-281 i 101 Marietta Street, Suite 2900 License Nos. DPR-32 Atlanta, Georgia 30303 DPR-37

Dear Mr. O'Reilly:

BETA RADIATION DOSE MEASUREMENTS EVALUATION SURRY POWER STATION UNIT NOS. 1 AND 2 On April 11, 1983, Virginia Electric and Power Company (Vepco) received a Confirmation of Action letter (CAL-280/83-01 and CAL-281/83-01) pertaining to the Surry Power Station. Item Number 3_ stated, "By July 5,1983, complete 'an evaluation to resolve the discrepancy between beta radiation dose measurements made with portable survey instruments and measurements made with thermoluminescent desimeters. Until this evaluation is completed, retain detailed survey records to provide sufficient information to adjust thermoluminescent dosimetry results, should such adjustment become necessary.

Also, until the above evaluation is completed, control personnel exposure to beta radiation based on dose rate measurements made with portable survey instruments".

In order to resolve this item, Vepco developed the following action plan:

1. Empirically identify the beta spectral components;

2. Detemine the response of the beta survey instrumentation (Eberline Model - RO-2A) to the identified spectra and determine a correction factor for this instrumentation;

3. Assess the beta dose to the lens of the eye as it relates to whole body dose;

4. Detemine if beta source similar to the identified station beta spectra '

is available;

5. Review the thermoluminescent dosimetry (TLD) beta dose algorithms with respect to the identified station spectra in order to determine if a correction factor is required; s

6. Expose TLD's to a beta slab source at known distances and dose rates to determine a TLD correction factor;

7. Compare the TLD dose algorithm for Sr/Y-90 to the correction factor detertined asing the beta slab source. ggrgfpfJ 8502090582 840809 PDR FOIA g4 -f[

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, y);r.o[n. Ei.ecraic .xn ro.an cour.w, to James F. 0 % illy leplementation of the action plan was initiated by acquiring numeraus swipes from Surry's Unit Number 2 primary system components. A Feather's analysis '

was performed on each swipe to determine the beta transmission. This procedure was then duplicated using swipes _ acquired from Unit Nu=ber 1. Both . ,s sets of data indicated a characteristic beta spectra whose major components' were Co-58/60 and Cs-134/137 having an average maximum beta energy of approximately 631 kev. This maximum beta energy approximates T1-204's maximum beta energy of 622 kev when attenuated by 20 centimeters of air. This data when compared to Eberline literature on the R0-2A indicated that a multiplication factor of 1.8 should be applied to beta survey data.

The maximum range of 631 kev betas is approximately 225 mg/cm . Comparing this range to the lens of the eye mass density thickness of 300 mg/cm' indicates that there is no beta contribution to the lens of the eye dose. The dose to the lens of the eye is solely a function of the photon component of the radiation field.

Inquiries of vendors concerning commercially available T1-204 beta slab sources indicated they are not readily available. Further inquiries indicated, however, that ' the University of Lowell has a T1-204 beta slab source which can be used for irradiation of Vepco's TLD's. The results of these irradiations will be used to complete aforementioned Items 6 and 7.

Discussions with the University of Lowell have revealed that the estimated time of performance of the mentioned irradiations and associated calibrations will require approximately 45 days. Subsequent analysis of the results and additional irradiations, if necessary, will also require approximately 45 days. ,

Therefore, it is requestad that an extension of 90 days from the July'5, 1983, completion date be granted to facilitate completion of the action plan as delineated in this letter. A final response will be submitted no later than October 7, 1983.

In the interim, we will continue to comply with the provisions of the Confirmation of Action letter with regard to beta dose rate surveys.

Very trul ours, a /

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W. L. Stewa t ec: Mr. Steven A. Varga Operating Reactors Branch No. 1 Division of Licensing Mr. D. J. Burke NRC Resident Inspector Surry Power Station p-w- w --+~s