ML20207E755

SER Supporting Removal of RCS Thermal Sleeves

ML20207E755
Person / Time
Site:	McGuire, Mcguire
Issue date:	12/30/1986
From:	Office of Nuclear Reactor Regulation
To:
Shared Package
ML20207E753	List: ML20207E748 ML20207E755
References
NUDOCS 8701050024
Download: ML20207E755 (2)

Text

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ENCLOSLT.E SAFETY EVALUATION REPORT REGARDihG RE!!0 VAL OF THERMAL SLEEVES t'CCUIRE NUCLEAR STATION, UNITS It.2 DOCKET NOS. 50-365 & 50-370 BACKGROUND For Westinghouse PURs, thermal sleeves have been traditionally installed at those reactor coolant system branch line nozzles where mixing of ficvs with different temperatures exists, such as at cozzles of safety injection lines, pressurizer surge lines, and charging lines.

Design evolution of the thermal sleeves has resulted in a total of five generations.

In 1982, cracking and failure was experienced in thermal sleeve attachment welds of certain operating Westinghouse reactors that used the " Generation 3" thermal sleeve design. Subseouently, Ucstinghouse reconnended that all

" Generation 3" thermal sleeves be removed, and orovided justification for operation of the affected plants without therral sleeves.

In 1983. McGuire Unit I removed all sleeves end McGuire Unit 2 started operations without sleeves installed. By License Condition 2.C.(4) of McGuire Unit 2 Facility Operating License NPF-17, the Commission required that "By December 31, 1983, the licensee shall provide, for NRC staff review and approval, justification for continued operation with the seven thermal sleeves removed from selected locations in the reactor coolant system." The required justification was submitted to the NRC by letter from Duke Power Company (the licensee) dated December 14, 1983.

The b'estinghouse recommendation and supporting analyses for plants with Generation 3 thermal sleeves were reviewed by the NRC staff. The NRC review concluded that plant operation without therral sleeves or with sleeves removed is acceptable, provided a program is implemented through requirements in the Technical Specifications to monitor the occurrence of injection ficw transients, and evaluate the fatigue usage factors for the affected nozzles. No action is required until the cumulative fatigue usage factor in a non-sleeved norrie approaches 0.8.

When that occurs, the Licensee should propose a plan for NRC approval to ensure early detection of possible nozzle oegradation.

In addition, for those nozzles retaining intact " Generation 3" therfral sleeves, a orogram to inspect attachment welds of these sleeves at each refueling outage should be initiated.

EVALUATION The staff position taken as a result of the above mentioned NRC review is intended to provide warning well in advance of piping failure. Sir,ce January 1980, NRC has required all Licensees to record the number and nature of actual transient occurrences that could significantly affect the fatigue life of reactor coolant piping or components, and to correlate that information with design assumptions used in analytical justification of such piping or compor.ents.

In this regard, McGuire Station Technical Specification 3/4.3.5.2 requires reporting of all ECCS actuations and injections, and the fatigue usage factor of each nozzle wherevtr its value exceeds 0.70.

Thus, the requirement for fatigue monitoring and reporting is met.

8701050024 861230

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Our review has concluded that McGuire Nuclear Station t.eetslconditons resditing

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from our review of plants with the Generation,3 thernal sleeve desier, ard c6r, be ocerated safely with the affected seven slee'ses'demoveqfrom Unit 1, and without thermal sleeves installed in Unit 2.

Accontinq7yj Urf t 2 License' ?.'

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Condition No. 2.C.(4) is satisfied and no further acMion,ih 4 quired.

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