IR 05000275/1986034
| ML16341E000 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 12/04/1986 |
| From: | Kirsch D, Mendonca M, Narbut P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML16341D999 | List: |
| References | |
| 50-275-86-34-MM, 50-323-86-32-MM, NUDOCS 8612120332 | |
| Download: ML16341E000 (8) | |
Text
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U. S.
NUCLEAR REGULATORY COMMISSION
REGION V
Report Nos. 50-275/86-34 and 50-323/86-32 Docket Nos. 50-275 and 50-323 License No.
DPR 80 and
Licensee:
Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 E
Facility Name:
Diablo Canyon Nuclear Power Plant Units 1 and
Inspection at:
Walnut Creek, California Inspection conducted:
November 24, 1986 M. M. Mendonca, Section Chief r~/) fg u Date Signed P. P. Narbut, Senior Resident 'Inspector Y~Zy/s r Date Signed Approved by:
D. F.
s
, Director Division of Reactor Safety and Prospects a
gne Su~azur:
Management meeting was held on November 24, 1986 on several problem areas and two apparent violations identified during routine inspection by the resident inspectors (Inspection Reports 50-275/86-29 and 50-323/86-27).
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MANAGEMENT MEETING DETAILS ATTENDEES Pacific Gas and Electric Company G. A. Maneatis, President J.
D. Shiffer, Vice President, Nuclear Power Generation R. C. Thornberry, Plant Manager, Diablo Canyon Power Plant J.
C. Carroll, Manager, Nuclear Operations'upport B. Lew, Director, Nuclear Regulatory Affairs J.
M. Gisclon, Assistant Plant Manager, Technical Services L. F. Womack, Operations Manager D. B. Miklush, Maintenance Manager T. L. Grebel, Regulatory Compliance Supervisor R.
S. Weinberg, News Services Representative Nuclear Regulatory Commission Staff 0,
J.
B. Martin, Regional Administrator B. H. Faulkenberry, Deputy Regional Administrator D. F. Kirsch, Director, Division of Reactor Safety and Projects A. E. Chaffee, Deputy Director, Division of Reactor Safety and Projects-J. L. Crews, Senior Reactor Engineer M. M. Mendonca, Section Chief, Project Section I P. P. Narbut, Senior Resident Inspector, Diablo Canyon Power Plant MEETING SUMMARY The meeting convened at approximately 1:00 p.m.
on November 24, 1986 in the Region V conference room.
Mr. Martin opened the meeting by indicating that the purpose of the meeting was to review the licensees performance, based on some recent events and NRC resident inspectors'indings (Inspection, Report Nos. 50-275/86-29, and 50-323/86-27).
Mr. Maneatis responded that the events and findings were of concern to himself and his staff and that efforts to address the issues were underway.
Mr. Maneatis then outlined a series of licensee presentations t'o address the events and findings:
Containment door mechanical interlock problems w'ould be addressed by Mr. Miklush; Snubber control problems would be addressed by Mr. Womack; Steam generator snubber pin, and main steamline isolation valve, check valve nut problems would be addressed by Mr. Gisclon; Operations attention to detail and configuration control would'e addressed by Mr.'oma'ck; and Root cause evaluation, and management follow-'p and awareness would be addressed by Mr. Thornberry.
y Mr. Shiffer then indicated that many of the problems were related to the Unit 1 refueling outage and that a critical assessment'f the outage activities was planned prior to the Spring 1987 outage for Unit 2 refueling.'r. Shiffer indicated that a large amount of work was accomplished during this current Unit 1 outage, that some activities went well (for example, radiation protection),
and that other activities (such as some of the topics for this management meeting)
needed improvemen P'f
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Mr. Miklush then presented a description of the containment personnel door mechanical inter'lock and associated problems.
This presentation closely paralleled the findings in the previously mentioned resident inspectors'eport.
Mr. Martin summarized the staff findings that these problems with the containment door interlock were not thoroughly investigated or understood by the licensee.
Further, Mr. Martin indicated that licensee management should closely examine their processes and their staff's understandings and directions for reacting and dealing with technical problems.
Mr. Womack then presented a description of the control of snubber problems which again paralleled the findings of the resident inspectors'eport.
Mr. Martin then summarized the staff's concerns as:
1.
Licensee management had not kept abreast of work scope and method in this area of snubber control; and 2.
Licensee management had not gotten to the root cause of the problem.
Mr. Womack stated that corrective actions were being taken by licensee management to maintain contact with work scope and to assure procedural compliance.
Mr. Gisclon's presentation commenced with an evaluation of a pin to a steam generator snubber that was found to be disengaged on September 12, 1986.
The licensee's review concluded that the pin was in place on September 10 based on two independent inspection activities.
The licensee also found two other pins on two different snubbers for the same steam generator that were to a lesser degree disengaged.
A multi-discipline task force was formed by the licensee to address this problem.
This task force included corporate engineering, Division of Engineering Research, security, and plant maintenance, operations and engineering personnel.
This task force postulated that the subject pins were "walked out due to vibratory motion."
This finding was based on the facts that:
(1) the disengaged pin had not dropped to the floor (2) grease marks on the pin indicated that it had moved and stopped at various times; (3) scratch marks on the pin from the allen screw indicated rotational and transverse motion; (4) a containment fan cooler, unit nearest the subject steam generator had relatively high vibrations; and (5) the steam generators had been undergoing filling and draining which changed their vibratory characteristics.
The licensee indicated that the use of an allen screw on a hardened pin may not be appropriate and that the allen. screw was last tightened about two years ago when the steam generator snubbers were overhauled.
The licensee has installed capture plates on Unit 1 that are double bolted to the snubber yoke with the thread disturbed so that the bolts would not back off.
This modification is also planned for Unit 2 at the next cold shutdown outage.
The licensee also had Westinghouse analyze the structural impact of a double design basis earthquake with the steam generator pin isengaged, and Westinghouse calculated that the systems would have thstood such an event.
Additionally, the licensee walked down the
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reactor coolant system and steamlines, and verified that system configuration 'as as'xpected.
Mr. Martin summarized the staffs concerns that the licensee had not sought corroborative evidence such as vibratory measurements, analytical verification, and laboratory tests.
Mr. Martin pointed out that this is another example similar to that on the containment door interlock problems where the licensee may not have done an acceptable root cause evaluation.
Mr. Gisclon then discussed the licensee's follow-up on the main steamline isolation valve check valve.
This presentation paralleled the resident inspectors'reviously mentioned report.
Mr. Martin indicated that this was a reasonable follow-up by the licensee on this problem.
Mr. Maneatis then indicated that the licensee's policy was to have their top people examine and identify problems and for the technical review groups (TRG) to get to the bottom of problems.
Mr. Shiffer indicated that a new program was being instituted to assure greater accountability for problem resolution.
Mr. Carroll indicated that the Onsite Safety Review Group was critiquing TRGs and these critiques were considered by the Plant. Staff Review Committee and the General Office Nuclear Plant Review and Audit Committee.
Mr. Martin concluded that the licensee management should closely examine their methods for dealing with technical problems, and take an aggressive role in setting plant staff attitudes which do not accept unresolved problems.
Mr. Martin also asked that Mr. Shiffer get back in touch with Mr. Martin on the resolution and follow-up of the containment door interlock and the steam generator snubber pin problems.
Mr. Shiffer indicated that additional administrative controls were planned to control clearances and system configuration for outages.
Mr. Martin asked if there were any topics that required further discussion and Mr. Maneatis indicated that the meeting had covered all points of interest.
The meeting so concluded at about 4:30 p.m.
on November 24, 198 CI
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