IR 05000275/1998013
| ML16342E227 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/17/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML16342E226 | List: |
| References | |
| 50-275-98-13, 50-323-98-13, NUDOCS 9808240076 | |
| Download: ML16342E227 (54) | |
Text
ENCLOSURE 1 U.S. NUCLEAR REGULATORYCOMMISSION
REGION IV
Docket Nos.:
License Nos.:
Report No.:
Licensee:
Facility:
Location:
Dates:
Inspector(s):
Approved By:
50-275 50-323 DPR-80 DPR-82 50-275/98-13 50-323/98-13 Pacific Gas and Electric Company Diablo Canyon Nuclear Power Plant, Units 1 and 2 7 1/2 miles NW of Avila Beach Avila Beach, California June 21, 1998 through August 1, 1998 David L. Proulx, Senior Resident Inspector Donald B. Allen, Resident Inspector Dyle G. Acker, Resident Inspector William P. Ang, Reactor Inspector Lee E. Ellershaw, Reactor Inspector Howard J. Wong, Chief, Reactor Projects Branch E
Attachment:
Supplemental Information
'7808240076 9808i7 PDR ADOCK 05000275 PDR
-2-EXECUTIVE SUMIVIARY Diablo Canyon Nuclear Power Plant, Units 1 and 2 NRC Inspection Report 50-275/98-13; 50-323/98-13 This inspection included aspects of licensee operations, maintenance, engine'ering and plant support.
The report covers a 6-week period resident inspection.
~Oe a 'ons The inspectors noted several minor errors in a sampling of two mqnths of control operator and shift foreman's logs. The amount of information entered in the logs have improved compared to previous reviews (Section 01.2).
Operator response to a high risk activity (work on 4 Kv panels for Bus G) was cautious and preparations were thorough.
The repair activity was well planned to prevent inadvertent loss of power to the vital bus (Section 01.3).
Ma'n enance The licensee provided good oversight and controls for testing of main steam safety valves.
The augmented testing of the MSSVs was scheduled and performed at the frequency specified in surveillance test Procedure STP M-77B, Appendix 7.1. 'The procedures governing the surveillance tests were technically adequate and personnel performing the surveillance demonstrated an adequate level of knowledge.
The inspectors noted that test results indicated that the MSSVs liftpoints meet the TS 3.7.1.1 requirements (Section M1.2).
Maintenance personnel demonstrated poor work practices in inadvertently leaving a check valve in a test gauge line. Although its installation did not impact the operability of the safety injection pump, it did raise concerns about the validity of the subsequent surveillance tests.
The check valve interfered with the measurement of a significant parameter used to determine pump operability, and could have masked actual degradation of the pump. The licensee's evaluation of the data logically led to the inspection of the suction pressure connection, which ultimately determined the cause, but the delay in review of the surveillance data from the April 27 test was a missed opportunity to correct the problem earlier (Section M1.3).
The effectiveness of the reorganization of Maintenance Services into asset teams is too recent to be evaluated.
The inspectors noted the implementation of oversight controls in that coaches and technical specialists have been assigned to assist and monitor the implementation of the new organization. Both positive and negative aspects of the new methods have been identified by the licensee, including a negative trend in performance (Section M6.1).
-3-Encnineeiinq The inspectors concluded that the licensee's operability evaluation (OE) for the Unit 1 containment fan cooler units (CFCUs) was adequate, pending a root cause of failure determination for CFCU 1-2.
However, the inspectors considered that there was a potential for the failure of CFCU 1-2 to be due to a common cause not yet recognized; therefore, the inspectors considered that it was prudent to remove CFCU 1-2 at the earliest opportunity, to verify that the suspected root cause was valid (Section E2.1).
Re ort Details Summa of Plan S a us Unit 1 began this inspection period at 100 percent power. On July 11, 1998, the unit power was down powered to 50 percent to replace control oil shuttle valves on main feedwater Pump 1-2.
The unit was returned to and remained at 100 percent power throughout the remainder of the inspection period.
Unit 2 operated at 100 percent power throughout this inspection period.
I. 0 eratio s
Conduct of Operations, 01.1 nera Commen s 71707 Using Inspection Procedure 71707, the inspectors conducted frequent reviews of ongoing plant operations.
In general, the conduct of operations was competent, professional and safety conscious.
a.
In ec'on Sco e 71707 The inspectors reviewed the control operator's and shift foreman's logs for the months of June and July.
b.
Observa io s and Findin s The inspectors reviewed the shift watch list and found, in general, that the personnel assigned to the fire brigade and minimum shift crew were properly designated.
However, several minor discrepancies were observed.
The shift watch list for day shift on June 11 did not designate which individuals were satisfying the TS minimum shift crew requirements for shift foreman or senior operator license.
By discussion with the shift foreman, it was apparent that the personnel were assigned on shift to meet these requirements and that this was an oversight in documentation only. In addition, the inspectors observed that blue ink is sometimes used, which results in poor or illegible photocopies.
One "summary of daily operations" log had not been signed by the shift foreman as reviewed.
The inspectors found a few log sheets that did not have the correct shift identified and several cases where shift turnover discussion topics were not checked off. These errors were identified to the shift foreman and properly resolved.
The inspectors noted, in general, more details have been included in the logs compared to previous review t
-2-c.
Conclusions The inspectors noted several minor errors in a sampling of two months of control operator and shift foreman's logs. The amount of information entered in the logs have improved compared to previous reviews.
01.3 0 era ions Res onse to Poenial Ris o Re airin 4 Kv Bus GAuxilia Power Cubicle Door a.
Ins ecionSco e 71707 On July 15, the inspectors observed operation's response to the potential for loss of startup power to the Unit 1, 4 KVvital Bus G while repairs were made to the auxiliary power cubicle door.
b.
Observations and Findin s While opening the door for auxiliary power cubicle, 52-HG-13, in order to perform surveillance test Procedure STP M-75, "4 Kv Vital Bus Undervoltage Relay Calibration" on Bus G of Unit 1, the technician found one of the cubicle door bolted fittings exhibiting galling. The seismic qualification of the cubicle required these bolts to be secure.
The bolt was found tight, but a work order was issued to repair the fitting. Although the breaker in this cubicle was open, the adjacent cubicle contained the startup power breaker, which was closed to provide power to the bus. The repair process required drilling out the existing fitting, with the potential for vibrations that could cause an inadvertent relay actuation that could trip the startup power breaker.
In preparations for this repair, oper'ations personnel verified all possible loads on the bus had been transferred to an alternate bus. The operators reviewed the expected effects of a loss of power to Bus G, and reviewed the applicable alarm response and bus restoration procedures.
The repair was designated a high risk activity, which resulted in additional administrative controls such as a detailed prework,briefing, interruption of other concurrent activities, and increased oversight by licensee management.
The inspectors observed the Operations Manager, Operations Director, Maintenance Manager, and Asset Team Leader in the control room during the briefing.
The repair was performed cautiously, using methods such as low speed drilling to reduce the risk of vibrations. The repair was completed without incident.
c.
Conc usions Operator response to a high risk activity (work on 4 Kv panels for Bus G) was cautious and preparations were thorough.
The repair activity was well planned to prevent inadvertent loss of power to the vital bu Miscellaneous Operations Issues (92700, 92901)
08.1 Closed Licensee Even Re o
LER 50-275323/96012 Revisions 0 and 1: reactor trips on Units 1 and 2 due to major western grid disturbances.
A major western grid disturbance o
Inspection Report
kilovolt
Licensing Amendment Request
Licensee Event Report
Nuclear Quality Services
Operability Evaluation
Reactor Coolant Pump
Refueling Water Storage Tank
Spent Fuel Pool
Technical Specification
Violation