ML20053D181
| ML20053D181 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 05/13/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20053D179 | List: |
| References | |
| NUDOCS 8206040161 | |
| Download: ML20053D181 (3) | |
Text
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 71 TO PROVISIONAL OPERATING LICENSE NO. DPR-19 COMMONWEALTH EDISON COMPANY DRESDEN STATION, UNIT NO. 2 DOCKET NO. 50-237
1.0 INTRODUCTION
By letter dated February 11, 1982, Commonwealth Edison Company (CECO) requested a technical specification change that would allow CECO to increase the main steam line radiation monitor set point during a hydrogen addition test that CECO plans to carry out during May and June of 1982.
The test involves the addition of hydrogen to the primary coolant to-lower the coolant free oxygen concentration by recombination. The reduction of free oxygen in the primary coolant is expected to reduce the extent of intergranular stress corrosion cracking of BWR piping.
.A by product of the oxygen suppression by hydrogen addition is an increase in the nitrogen carry over in the steam and an increase of the radiation background in the main steam lines caused by N-16,
.Because of the anticipated increase in the main steam line radiation level, CECO has proposed that the steam line radiation monitor set point be increased by no more than 25% during those porti6ns of the test when the hydrogen addition rate is less than or equal to 13 SCFM and by a factor of 3 and 8 for the two four hour portions of 'the test when the hydrogen addition rates are 31 and 62 SCFM respectively.
v 2.0 DISCUSSION AND EVALUATION _
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CECO has described the radiation protection considerations particular to the Hydrogen Addition Test and has described measures which will assure that occupational exposure will be as low as is reasonably achievable
,,ALARA).
Normal radiation protection /ALARA practices and procedures will
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continue in effect during the course of the test.
In addition, special l
surveys to monitor the expected main steam system dose rate increases.will be routinely performed, emphasizing accessible affected areas.
Special considerations for the radiation energies have been made. The dose rate increases anticipated during the test will be minimized by limiting H2 l
addition for most of the duration of the test.
Dose rates are not expected to exceed 1.2 times normally measured dose rates.
Two, four hour test l
8206040161 820513 PDR ADOCK 05000237 i
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2-segments are planned where doses are anticipated to reach a maximum of eight times normal.
These tests are planned for periods when personnel
- access can be minimized. Access control areas will be established to control access and restrict personnel entry to areas where high. does rates are measured, such as high radiation areas expected at the main steam line sample point during maximum hydrogen addition periods.
Since the test is of short duration (vone month), and dose rate increases are minimal, shielding will not be generally employed.
Local shielding will be available as needed for locations such as sample points during the special four hour test segments.
During porti6ns of the test, radiation monitor setpoints will be increased.
The capability to edter foi tuel element failures, which could result in increased occupational doses, i's maintained through: the continued capa-bility of the radiation monitor to detect failures at the partial hydrogen addition' levels (<25% increase most of the test); the performance of daily primary water analyses and the trends of these analyses; routine surveys, and the capability of downstream process monitors, such as the steam jet air ejector, to detect radioactivity from fuel failure. The test proce-dure has undergone ALARA review by General Electric personnel and pr,ofes-sional heal _th' physics personnel at the facility; ALARA/ radiation protection considerations are integrated into the test.
In general the licensee will control occupational exposure to an ALARA level through such means as restricting access through the use of RWP's, controlling access through the use of access control points, performing surveys to identify dose rate increases and high dose rate areas, controlling the dose rate increases and high dose rate areas, controlling the dose rate increases to a level only slightly above normal levels, minimizing the number of personnel exposed, utilizing temporary shielding as needed, and providing test coverage by radiation protection an'd test personnel. These actions are consistent with Regulatory Guide 8.8, "Information Relevant to Ensuring That Occupational Radiation Exposures at Nuclear Power Stations Will Be As Low As Reasonably Achievable" and other NRC staff guidance and are '
acceptable.
Based upon the 'above considerations we conclude that the Technical Specifications should be changed to permit the main steam line radiation monitor set point to be increased to account for the increased Nitrogen-16 background that will occur during this Hydrogen Addition Test.
3.0 ENVIRONMENTAL CONSIDERATION
We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
k 3-4.0 C0tlCLUSI0ft We have concluded, based on the considerations discussed above, that: (1) because the amendment does not involve a significant increase in the pro-bability or consequences of accidents previously considered and does not involve e eignificant decrease in a safety margin, the amendment does not involve a significant hazards consideration, (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance sith the Commission's regulations and the issuance of the amendment will not be inimical Eto the common defense and security or to the health and safety of the public.
Date:
May 13, 1982 O
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