ML20198N993
| ML20198N993 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Oyster Creek |
| Issue date: | 03/19/1986 |
| From: | Woodhead C NRC |
| To: | Lombardo J, Smith H NRC |
| Shared Package | |
| ML20151H203 | List:
|
| References | |
| FOIA-86-26 NUDOCS 8606060215 | |
| Download: ML20198N993 (3) | |
Text
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Note to: Jim Lombardo Hazel Smith From:
Colleen P. Woodhead Through: Joe Gray
SUBJECT:
0YSTER CREEK CORE SPRAY SPARGER AMENDMENT I am returning the Oyster Creek amendment package concerning an additional cycle of operation with cracked core spray sparger without concurrence and with recommendation that the proposed amendment be prenoticed again.
The reason for this is that the original prenotice and proposed NSH finding were based on reasons for confidence in safe operation which are contradicted by the safety evaluation accompanying the amendment.
The major differences in the. underlying bases for supporting the issuance of the amendment are set out below.
2 A.
The prenotice and NSH finding was based on new improved photographic inspection showing less cracking than previously indicated.
In the original prenotice package supporting a finding of no significant hazards, it was stated, on p. 2. that During the current refueling outage, the licensee has completed full inspection of the accessible surfaces and welds of the sparger and repair assemblies using new inspection techniques and computer photo enhancement and has compared indications of cracks to previous indications.
The new inspections and analyses appear to show that:
(1) many previous indications of cracks from prior inspections are, in fact, not cracks; (2) no further degradation of the sparger has occurred since the prior inspections; and (3) susceptibility to new cracking... in new locations is reduced by stress relief from existing cracks.
The staff has concluded that continued operation of the facility can be permitted if the extent of sparger cracking remains as evaluated in the SER supporting Amendment 47.
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s To ensure that no degradation in performance of the sparger will occur, the licensee will perform full inspections of the accessible surfaces and welds of both core spray spargers and repair assemblj_es at each refueling outage.
b Because, subject to NRC Staff confirmation prior to issuance of the proposed amendment, the magnitude of sparger cracking is not as severe as previously indicated, there has been rio additional degradation during the last fuel cycle, and the repair bracket assemblies should maintain the integrity of the existing sparger... the NRC Staff proposes to determine that issuance of the proposed amendment authorizing operation with the existing repaired sparger without further degradation until the end of life does not involve a significant increase in the probability or consequences of accidents previously considered (etc.)...
The October 26, 1983 Federal Register notice containing the proposed NSH determination stated the finding was based on the new inspections showing less cracking than previously believed.
B.
The Amendment Safety Evaluation states the photographic inspections are inconsistent and unr'eliable and puts in question the amount of cracking.
The Safety Evaluation accompanying the amendment, sent for OELD concurrence, significantly contradicts the basis for NSH in the prenotice. The SE states that the reports by GPU of the extent of cracking in the years 1978-1983 are inconsistent; that the 1982 evaluation by 3 NDE qualified inspectors of the 1980 video tapes, indicating cracking whereas the 1983 video tapes show none, demonstrates that the examination procedure " lacks a confirmed reliability" and the possible reasons for this are explained.
SE, p. 2.
The SE further states that since the replacement of the spargers is to be deferred " based on evidence that no major progression of cracking has occurred" an inspection method which is sensitive enough to allow crack measurement i
is necessary but that the method used at Oyster Creek " precludes the assignment of the reliability on the crack length measurement u?on which the deferment of replacement of the spargers could be based."
ievertheless, after stating that the method used at Oyster Creek is unreliable, the SE then states that it is " adequate to detect whether there is a major progression of existing cracks," and concludes that " major progression, while currently unquantifiable, has not occurred and operation with the present spargers for another fuel cycle is acceptable." The SE states that future inspections "by a method acceptable to the NRC" (undefined) will be performed for meaningful comparisons.
However, several methods of inspection are described on pp. 2-3 of the SE and declared impractical.
Thus, the SE essentially states that the previous inspections are unreliable so that we do not really know how much cracking has occurred but that another cycle of operation is approved because the licensee will use some
o undefined (and perhaps nonexistent) method of inspection in the future outages which will provide reliable information.
Given the radical difference in the NSH prenotice and the SE for the amendment,Tsuggest that the SE be rewritten to explain (if possible) the reason. Staff believes there is reasonable assurance that Oyster Creek can continue to operate with the cracked sparger without significant risk to the public and then renotice this amendment with opportunity for hearing (eliminating the proposed NSH finding).
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