ML19257D159
| ML19257D159 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 01/16/1980 |
| From: | Joseph Austin NRC COMMISSION (OCM) |
| To: | NRC OFFICE OF THE SECRETARY (SECY) |
| References | |
| NUDOCS 8002010431 | |
| Download: ML19257D159 (2) | |
Text
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UNITED STATES Docket No. 50-266 f f,f ]
NUCLEAR REGULATORY COMMISSION
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MEMORANDUM FOR:
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PARTIES TO WISCONSIN ELECTRIC POWER COMPANY PROCEEDING (POINT BEACH STEAM GENERATOR TUBE DEGRADATION)
FROM:
John H.
Austin, Technical Assistant to Commissioner Gilinsky
SUBJECT:
MEETING WITH PETER ANDERSON OF WISCONSIN ENVIRONMENTAL DECADE On January 2, 1980, Peter Anderson of Wisconsin's Environmental Decade entered my office and asked if he could discuss several matters regarding the Point Beach steam generators and the NRC staff briefing on the same that was to occur later in the morning.
Since I was not aware of the Decade request for a hearing on the subject, I agreed.
Mr. Anderson summarized the recent history of tube degradation, noting that all tubes at Point Beach had been tested during the October refueling outage.
However, he indicated in subsequent tests (performed after the December 11 shutdown) 20 new tubes were found to have indications of degradation, but that these degradations were not identified in the earlier tests.
Farther, Mr. Anderson noted the existence of an LER in mid-November reporting that, during the October outage, 5 tubes were identified as having defects above the tube sheet.
He stated that, based on licensee reviews of old eddy current test (ECT) tapes, the licensee claims the defects were old, perhaps from the 1974 time frame, and not indicative of continued degradation above the tube sheet.
Mr. Anderson also noted that the American Physical Society (APS) study group report of 1975 concluded that failure of from 1 to 10 tubes above the tube sheet could present a serious safety concern.
Based on the above, Mr. Anderson identified several issues that should be addressed.
The first issue was:
should there be a blind review of old ECT tapes by impartial experts (such as individuals from BNL) to independently determine
,zhether the 5 defective tubes identified in the LER were in fact cld defects.
He noted that ECT is more an art than 1855 005' 3 00201olL 1
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science and questioned the degree of assurance one could have on a conclusion that the 5 defective tubes were in fact old defects.
He also recommended determing whether NRC staff accepted the APS study group position on the number of tube failurer 2using a safety concern.
Mr. Anderson...dicated that two tubes had been pulled for metallurgical examinations and ECT.
ECT of one tube confirmed the metallurgical tests while the other tube showed no defects based on ECT but 33% metallurgical defects.
He indicated that he had been informed that for degradation in the range of 40 to 90%, the degradation rate was exponential as opposed to linear.
Mr. Anderson raised this question:
if one cannot detect degradations below 30% by ECT, how can one discount runaway degradation.
Mr. Anderson pointed out that it had previously been claimed that if the temperature was reduced on the hot side of the tubes, then degradation would be arrested.
However, there were 20 additional tubes identified as having defects following a reduction in temperature.
He questioned how a pressure change could do that which a temperature change could not.
He also questioned whether a pressure change would reduce the margins of safety.
Mr. Anderson concluded by noting he had submitted relevant documents on the subject, asked that I review them, and expressed a willingness to discuss the issues over the phone at a later date.
In accordance with Section 2.780(c), I am hereby notifyinc the parties to the proceeding of the meeting and of the thrust of the communication.
1856 006