ML20105D110
| ML20105D110 | |
| Person / Time | |
|---|---|
| Site: | Surry, 05000000 |
| Issue date: | 10/07/1983 |
| 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: |
| References | |
| FOIA-84-574 242B, CAL-280-83-01, CAL-280-83-1, CAL-281-83-01, CAL-281-83-1, NUDOCS 8502090596 | |
| Download: ML20105D110 (2) | |
Text
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- w. L. srmwiar vare P===inen October 7, 1983 Nretuam oramations Mr. James P. O'Reilly Serial No. 242B Regional Administrator N0/WDC: ace Region II Docket Nos. 50 c80jD U. S. Nuclear Regulatory Commission 50-101 Marietta Street, Suite 2900 License Nos. DPR-32 Atlanta, Georgia 30303 DPR-37
Dear Mr. O'Reilly:
BETA RADZATION 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 dosimeters.
Until this evaluation is completed, retain detailed survey records to provide sufficient information to adjust thermoluminescent dosimetry results, should suc'c 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 actio'n plan:
1.
Empirically identify the beta spectral components; t
2.
Determine the response of the beta survey instrumentation (Eberline Model - RO-2A) to the identified spectra and determine a correction factor for this instrumentation; i
3.
Assess the beta dose to the lens of the eye as it relates to whole body l
dose; 4.
Determine if a beta source similar to the identified station beta spectra I
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; 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 determined using the beta slab source.
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A Vamo wa Etscraic an Powr= COMPANY TO James P. O'Reilly In our letter of July 1, 1983 (Serial No. 242A), Vepco addressed Items 1 through 3 and requested a 90-day extension to address Items 4 through 7.
These items have been completed.
The University of Lowell performed the necessary irradiations of the TLD badges using a thallium-204 beta source with an attenuated beta spectral caximum energy of 628 kev.
The results of the irradiations indicated that a correction factor of 2.25 should be applied to the Teledyne strontium /
yttrium-90 beta dose algorithms.
Personnel exposure records for the first two quarters of 1983, when the highest beta dose rates ever experienced at Surry were encountered due to failed fuel, were thoroughly examined. The newly determined correction factor was applied to the " worst case" skin dose assignment.
The resultant total skin dose was calculated to be less than Vepco's administrative limit of 5.0 rem per quarter and well below the regulatory limit of 7.5 rem per quarter.
Based on this fact and since skin dose limits apply only to current quarter exposure (i.e., there is no annual or lifetime limit), adjustment of previous quarterly skin dose records is not considered necessary.
Required procedural changes to incorporate the findings of our evaluation will be accomplished by October 15, 1983, and the new correction factor will be utilized to assess exposures received on or after October 1, 1983.
Very truly yaurs, W. L. Stewart cc:
Mr. Steven A. Varga Operation Reactors Branch No. 1 Division of Licensing Mr. D. J. Burke NRC Resident Inspector Surry Power Station L