ML20010E578
| ML20010E578 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 08/20/1981 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20010E575 | List: |
| References | |
| NUDOCS 8109040287 | |
| Download: ML20010E578 (3) | |
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UNITED STATES p,
NUCLEAR REGULATORY COMMISSION
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WASHINGTON, D. C. 20555 e
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p SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMIN1 NO. 65 TO FACILITY OPERATING LICENSE NO. NPF-1 PORTLAND GENERAL ELECTRIC COMPANY THE CITY OF EUGENE, OREGON PACIFIC POWER AND LIGHT COMPANY TROJAN NUCLEAR PLANT DOCKET NO. 50-344 Introduction By letter dated June 29, 1981, Portland General Electric Company, ~et al.,
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(the licensee) requested a change to the Technical Specifications appended to Facility Operating License No. NPF-1 for operation of the Trojan Nuclear Plant in Columbia County, Oregon. The proposed changes relate to the inservice inspection program for the Cortrol Building connection bolts.
Discussion and Evaluation Pursuant to the Initial Decision of the Atomic Safety and Licensing Board dated July 11, 1980, the NRC issued Amendment No. 47 to Facility Operating License No. NPF-1 for the Trojan Nuclear Plant on July 25, 1980. That amendment consisted of license conditions and Technical l
Spacifications related to the Control Building modification program, which authorized structural modifications to the Control Building to l
j substantially restore the originally-intended seismic design margins.
The major part of the modification program, which is now complete, l
consisted of adding a new structural wall and a thick (3") steel plate along column line R and increasing the thickness of the wall at columo I
line N of the Control Building. The new structural elements are clampeo together with heavy steel bolts to ensure that these elements act as a unit under earthquake forces.
The Technical Specifications issued with Amendment No. 47 included an inservice inspection program to ensure that the ciamping force produced by the bolts is maintained at an adequate level for the life of the plant. The present program consists of periodic testing of a sample of bolts for proper tension and a visual and ultrasonic examination designed to detect bolt degradation (bolts not removed).
8109040287 810820
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DR ADOCK CSOOO344 p
- o By letter dated June 29, 1981, the licensee proposed a revision to the method to be used to detect bolt degradation.
The present specification requires each bolt in the sample
- tc be examined by an in-situ ultrasonic test inspectica for evidence of cracks or other abnoniaf degradation. This method for testing (ultrasonic) was developed under the assumption that these bolts, under normal circumstances, would never be removed from the walls.
Original construction plans called for each bolt to be wrapped with Teflon tape to serve both as a bond breaker for the grout and as a corrosion inhibitor. Changes to the construction plans resulted in the need to move the bolts after pouring the grout. Therefore, the Jicensee changed the corrosion inhibitor to grease. since novement of the bolt in the grout cylindar would have damaged.,he integrity of the Teflon tape.
With this change, the bolts became removable-The licensee has therefore proposed, in lieu of in-situ ultrasonic examination, that 10%** of the total number of bolts Fe removed from the walls and examined by surface examination techniques (e.g. magnetic particle) for evicence of cracks In addition, the grease for each bolt or other abnormal degradation.
removed will also be checked for presence, consistency, appearance and If cracks to assure that it is within specification for water content.
or other degradation are discovered in any one bolt, two adjacent bolts would be similarly examined.
If problems are found in either of these, then all bolts would be examined.
We have reviewed the revised program as described above and concur i
with the licensee that it represents a more comprehensive inservice inspection program than that currently contained in the Technical Specifi-There have been recent cases wherein ultrasonic examination cation..
c has fai.ed to detect defects in bolts which were readily observable by visual inspection. Therefore, the revised program of bolt removal and surface examination should provide added assurance of bolt integrity.
In addition, bolt removal, handling, and preparation for surface examination will at the same time allow a visual examination of the bolts, and the corrosion inhibitor as well. We conclude that the proposed changes l
are acceptable.
Sample size is not less that 25% of the total number of bolts, dropping to 10% if the results of the first four inspections meet specified acceptance criteria.
- 5% after the first four inspections, if satisfactory results achieved.
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. 9 Environmental Consideration We have determined that the amendment does not authorize a change in effluent tyoes or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have furtter concluded that the amendment involves an action which is insignificant fror,' the standpoint of environmental impact and, pursuant to 10 CFR 551.5(d)(4), that an environmental impact statement or negative declaration and environ-mental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion
'r!e have concluded, based on the considerations discussed above, that:
(1) because the amendment does not involte a significant increase
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f a the probability or consequences of accidents previously considered and does not involve a significant 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 with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: August 20, 1981 i
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