IR 05000275/1992001
| ML17083C402 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/28/1992 |
| From: | Morrill P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML17083C399 | List: |
| References | |
| 50-275-92-01, 50-275-92-1, 50-323-92-01, 50-323-92-1, NUDOCS 9203170153 | |
| Download: ML17083C402 (28) | |
Text
U.S.
NUCLEAR REGULATORY COMMISSION REGION V
Report Nos:
50-275/92-01 and 50-323/92-01 Docket Nos:
50-275 and 50-323 License Nos:
Facility Name:
Inspected at:
Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 Diablo Canyon Units
and
Diablo Canyon Site, San Luis Obispo County, California Inspection Conducted:
January 1 through February 3, 1992 Inspectors:
H. Wong, Senior Resident Inspector M. Miller, Resident Inspector D. Acker, Reactor Inspector, Region V
Approved by:
P. J.
Mo ri
, Chief, eactor ProJects ection ate igne Summary:
Ins ection from Januar 1 throu h Februar
1992 Re ort Nos.
50-275/92-01 and 50-323/92-01 d:
it i
i i
Id d operations, maintenance and surveillance activities, followup of onsite events, open items, and licensee event reports (LERs),
as well as selected independent inspection activities.
Inspection Procedures 37828, 41500, 61726, 62703, 71707, 71710, 92700, 92703, and 93702 were used as guidance during this inspection.
Safet Issues Mana ement S stem SIMS Items:
None Results:
General Conclusions on Stren ths and Weaknesses:
Strength -
On January 9, 1991, during a routine plant tour, the licensee's chemistry manager identified that the auxiliary building sump had begun to overflow through floor drains on the 54 foot elevation of the auxiliary building.
The chemistry manager's timely observation demonstrates the benefits of plant tours by licensee managers.
This occurrence is described in paragraph 4.a.
9203170153 920228 PDR ADOCK 05000275 G
e E
Meakness
- Licensee corrective actions were inadequate in preventing the recurrence of the undetected fai lure of a reactor cavity sump level instrument.
An NRC inspector identified a failed reactor cavity wide range sump level instrument during the followup to a previous failure in 1990.
This occurrence is described in paragraph 12.a.
Si nificant Safet Matters:
None Summar of Violations and Deviations:
A violation was identified involving the licensee's inadequate corrective actions to preclude the recurrence of an undetected failure of a reactor cavity wide range instrument in Unit 2.
An NRC inspector identified in October 1991 that a reactor cavity level instrument had failed.
The instrument had failed for over 7 days and had not been detected by licensee personnel.
The same failure occurred in 1990 when both reactor cavity wide range level instruments failed and was undetected for over two months.
0 en Items Summar
Three new items were opened, eight items closed, and one item remains ope DETAILS Persons Contacted Pacific Gas and Electric Compan
- J. D. Shiffer, Executive Vice President
- G. M. Rueger, Senior Vice President and General Manager, Nuclear Power Generation Business Unit
- J. D. Townsend, Vice President and Plant Manager, Diablo Canyon Operations W. H. Fujimoto, Vice President, Nuclear Technical Services
- D. B. Miklush, Manager, Operations Services
- M. J. Angus, Manager, Technical Services
- B. W. Giffin, Manager, Maintenance Services
- W. G. Crockett, Manager, Support Services
- J. E. Molden, Instrumentation and Controls Director
- W. 0. Barkhuff, guality Control Director R. P. Powers, Mechanical Maintenance Director
- D. A. Taggart, guality Performance and Assessment Director
- T. L. Grebel, Regulatory Compliance Supervisor H. J. Phillips, Electrical Maintenance Director
- R. C. Anderson, Manager, Nuclear Engineering and Construction Services J.
A. Shoulders, Onsite Project Engineer S.
R. Fridley, Operations Director R.
Gray, Radiation Protection Director
- J. J. Griffin, Senior Engineer, Regulatory Compliance J.
V. Boots, Chemistry Director
- J. B. Hoch, Manager, Nuclear Safety and Regulatory Affairs
- T. A. Moulia, Assistant to Vice President Diablo Canyon Operations
- C. A. Dougherty, (}uality Assurance Senior Supervisor
- R. C. Russell, Nuclear Safety and Regulatory Affairs
- Denotes those attending the exit interview The inspectors interviewed several other licensee employees including shift supervisors, shift foremen (SFM), reactor and auxiliary operators, maintenance personnel, plant technicians and engineers, and quality assurance personnel.
0 eration Status of Diablo Can on Units 1 and
During the inspection period, Units 1 and 2 operated at essentially lOOX power except for a few days (January 18-21, 1992), during which Unit 2 reduced power to 50K and then increased power to 90K to investigate leaking tubes in feedwater heater 6A.
Unit 2 returned to 100K power on January 21, 1992.
Unusual Event Declared Due to Minor Earth uake 93702 On January 17, 1992, at 0036 PST, an Unusual Event was declared by licensee personnel based on the occurrence of an earthquake felt by some plant personnel and recorded by plant seismic instrumentatio Units i a<>ent Re ort (LER) Followup (92700 a.
LER 50-275/91-016-00:
Missed Surveillance of Airlock Door Seals due to Personnel Error C osed b.
The LER involves the licensee's failure to perform surveillance testing of the containment personnel airlock door seals when the automatic tester was inoperable.
From the period June 11, 1991,,to September 27, 1991, 17 containment entires were made without the appropriate leak test being performed.
During this period, on six occasions a manual leak test was performed which demonstrated acceptable door seal performance.
The licensee performed a
successful leak test after the missed surveillance tests were identified on September 27, 1991.
The automatic leak tester was repaired and returned to service.
As part the corrective actions for this event, the licensee prepared an Operations Incident Summary regarding this event, revised the daily shift checklist to clarify the operability checks for the automatic tester, prepared a standard clearance for work on the leak tester with a specific note to perform the conditional surveillance test, revised surveillance testing to specify a functional test of the leak tester every 6 months, and will review other equipment which are used to automatically satisfy Technical Specifications surveillance requirements.
These actions appear appropriate.
The licensee stated in the LER that operations training would be revised to incorporate additional details on the leak monitor; however, the latest training lesson plan was dated early September 1991 (prior to the event).
Discussions with training personnel indicated that while the lesson plan had been recently revised, there were additional aspects which should be added to the lesson plan to reflect the lessons from the event.
In addition, the NRC inspector questioned the appropriateness of the non-quality classification of the leak tester.
This question had not been resolved prior to the end of the reporting period.
Followup to this event is also being tracked under Unresolved Item 50-275/91-27-01.
LER 50-275/91-016 will be closed and Unresolved Item 50-275/91-27-01 will remain open pending resolution of the lesson plan and quality classification issues.
LER 50-275/91-04-00:
Loss of Offsite Power Durin Refuelin Closed On March 7, 1991, the licensee experienced a loss of offsite power event during refueling as a result of crane approaching too close to the high voltage lines supplying offsite power and causing an arc to ground.
Maintenance personnel were lifting a relief valve and did not understand that the lines were energized.
The Augmented Inspection Team investigation documented its results in Inspection Report 50-275/91-09 and open items were documented in this report.
Because NRC followup action for the event is tracked
by 'the open items in Inspection Report 50-275/91-09, this LER is closed.
No violations or deviations were identified.
12.
0 en Item Followu 92703 a ~
Unresolved Item 50-323/91-31-01:
Ino erable Wide Ran e Reactor Cavit um Leve Channe ose Between August 21, 1990, and November 6, 1990, both reactor cavity sump wide range level channels in Unit 2 were inoperable in violation of Technical Specification (TS) 3.3.3.6.
The licensee issued Licensee Event Report (LER) 2-90-010, Revisions 0 and 1, to describe this event.
Included in the LER were cprrective actions to preclude recurrence.
During an NRC inspection conducted October 7 through October 25, 1991, (Inspection Report 50-275, 50-323/91-31)
an NRC inspector identified on October 22, 1991, that one of two reactor cavity sump wide range level channels, 942A, in Unit 2, was inoperable.
The licensee restored the channel to an operable condition.
On October 23, 1991, the inspector.,again identified the channel as inoperable.
The licensee again restored the channel to an operable condition.
The licensee and the inspector reviewed the records for reactor cavity sump level channel 942A.
The licensee identified that the channel had become inoperable on October 10, 1991.
The licensee entered Node 3 on October 15, 1991, at 9:58 a.m., with channel 942A inoperable.
The inspector reviewed the 1990 failure and concluded that:
1)
a normal channel indication of 0 was difficult to distinguish from a failed channel indication of slightly below 0; 2) reactor cavity sump level channel 942A was subject to intermittent failure from an unknown cause; 3) monthly surveillance testing of the reactor cavity level channels did not always identify failed channels; and 4) the
'afety parameter display system (SPDS) indication which could identify a failed channel was not being routinely monitored.
Based on this information, the inspector concluded that the licensee's 1990 corrective actions were not adequate to ensure that reactor cavity sump wide range level channels remained operable in accordance with TS requirements.
The apparent failure of the licensee to take effective corrective action was considered an unresolved item (50-323/91-31-01)
pending the licensee's determination of root cause and review of TS requirements.
On November 9, 1991, the licensee identified that channel 942A had again failed.
The licensee stated that the cause could not be determined.
The channel was restored to operable conditions by down-powering and re-powering the unit power supply.
As a compensatory measure the licensee added a surveillance requirement to check the SPDS critical safety functions daily, including channel 942A.
The licensee also added labels to the SPDS monitor to clearly explain the indications for failed channel I ~,
~ 2 b.
On November 22, 1991, the licensee issued LER 50-323/91-010 concluding that between 9:58 a.m.
on October 15, 1991, and 9:15 p.m.
on October 22, 1991, the channel had been inoperable in Nodes 1, 2, and 3 for greater than 7 days contrary to TS Action. Statement 3.3.3.6.a.
This is an apparent violation of NRC requirements (Item No. 50-323/92-01-03).
On December 17, 1991, channel 942A failed again.
The licensee reported that detailed voltage checks taken before and after this failure did not show the cause of the failure.
The licensee was continuing to investigate this problem during the time of this inspection report.
Unresolved Item 50-323/91-31-01 is closed and remaining corrective actions, including measures to assure that the surveillance program will detect failed Technical Specification equipment, will be followed through Open Item No. 50-323/92-01-03.
Unresolved Item 50-275/91-27-01:
Automatic Airlock Tester Isolated forSDa s
Oen co This item is discussed in paragraph ll.a above.
This item remains open.
Followu Item 50-275/91-01-01:
Loss of Control Room Emer enc Li htina Closed During the loss of offsite power on March 7, 1991, Unit 1 control room emergency AC lighting was lost.
Subsequent investigation found that during earlier maintenance work on vital bus H, the control room's emergency AC lighting had been aligned to non-vital power.
This action had not been tracked and the alignment was not restored to the normal lineup after the work was completed.
As corrective action, the licensee issued an Operations Incident Summary, which included emphasis on the importance of proper status control of components and specific review of the operation of control room lighting.
Also, the licensee determined that the label for the lighting switch backup power position should be changed to
"alternate" rather than
"emergency" and that appropriate procedure changes should be made to be consistent with this change.
The inspector found that new labels had been added.
The licensee stated that procedure changes would be performed by the end of March 1992.
Based on the licensee's corrective action, this item is closed.
d.
Followup Item 50-275/91-09-06:
Traffic Near Offsite Power Su plies Closed After the 1 oss of offs ite power on March 7, 1991, the 1 icensee committed to control vehicles and install physical barriers near offsite power supplie ~
~
I
e.
The inspecto~
walked down the barriers on both units and reviewed training of vehicle operators, including security escorts and operators of man-lifts (for example, painters).
Barriers had been installed and maintenance and operations personnel are required to be trained in vehicle and crane operation.
The inspector discussed the issues with several licensee employees, including managers, operators, riggers, heavy equipment operators, and outage work planners.
All of the individuals interviewed appeared to be sensitive to the need for the availability of multiple power sources during outages and the avoidance of loss of offsite power events by vehicle control.
Most of the individuals had actively participated in the corrective actions as a result of the March 7, 1991, loss of offsite power and in corrective actions in response to other industry events.
This item is closed.
Followu Item 50-275/91-09-07:
Assessment of the Event Review rocess ose After the March 7, 1991, loss of offsite power event, the licensee committed to strengthen the event review process.
The inspector reviewed procedure AP C-14, Processing of 'Industry Experience.
The procedure had been changed to require a structured process for the review of industry events and to require a higher level of review responsibility and accountability for significant-industry events.
The inspector reviewed the results of reviews of recent industry events performed according to AP C-14 and observed that the assessments appeared to have included engineering and operations concerns specific to Diablo Canyon.
The reviews had been completed and assigned for corrective action.
Based on the licensee corrective actions, this item is closed.
Followu Item 50-275/91-09-08:
Safet Assessment and Control of Activities Durin Outa es Closed As corrective action associated with the March 7, 1991, loss of offsite power, the licensee committed to complete an outage policy and program summaries for safety assessment and control of activities during outages.
The inspector reviewed progress on the licensee's safety assessment and control of activities during outages.
The licensee had taken several measures to ensure availability of other significant safety requirements.
The following are noteworthy:
Shutdown risk guides have been developed to address control of such items as reactivity, inventory, containment closure, core and spent fuel pool cooling, and vital electrical supplies.
These are under review and expected to be implemented during the upcoming Unit 1 refueling outag A
An outage work schedule for Unit 1 is under development to limit the unavailability of power sources.
The shutdown risk findings of an EPRI and Westinghouse audit at a similar plant have been reviewed for applicability to Diablo Canyon.
The maintenance of the offsite switchyard will be coordinated between Diablo Canyon and offsite PGEE organizations.
Westinghouse, EPRI, and INPO will perform an audit of the plans for Diablo Canyon's outage and assess risk during shutdown.
Based on the licensee's corrective actions, this item is closed.
g.
Followu Item 50-275/91-09-09:
Guidelines for Restoration of Power an oo sn urban uta es ose After the March 7, 1991, loss of offsite power event, the licensee committed to prepare baseline coping strategies for restoration of power and cooling before the next refueling outage.
The inspector noted that the licensee prepared procedures OP AP SD-l, Loss of AC Power; OP AS SA-2, Loss of RCS Inventory; OP AP SD-3, Loss of Auxiliary Salt Water; OP AP SD-4, Loss of Component Cooling Water; and OP AP SD-5, Loss of Residual Heat Removal.
The licensee stated that these procedures were written specifically for modes 5 and 6 when the plant is shutdown and in refueling outage.
Based on the licensee's corrective actions, this item is closed.
One violation (Paragraph 12.a
) was identified.
13.
Exit On February 5, 1992, an exit meeting was conducted with the licensee's representatives identified in Paragraph 1.
The inspectors summarized the scope and findings of the inspection as described in this repor ~
0