IR 05000275/1991013
| ML16341G194 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 07/11/1991 |
| From: | Morrill P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML16341G193 | List: |
| References | |
| 50-275-91-13, 50-323-91-13, NUDOCS 9107290059 | |
| Download: ML16341G194 (22) | |
Text
U.S.
NUCLEAR REGULATORY COMMISSION REGION V
Report Nos:
50-275/91-13 and 50-323/91-13 Docket Nos:
,
50-275 and 50-323 License Nos:
Pacific Gas and Electric Company 77 Beale Street, Room 1451 San Francisco, California 94106 Facility Name:
Diablo Canyon Units 1 and
Inspection at:
Diablo Canyon Site, San Luis Obispo County, California Inspection Conducted:
April 28 'through June 7, 1991 Inspectors:
P.
P. Narbut, Senior Resident Inspector K. E. Johnston, Resident Inspector Approved by:
orr
,
se
,
actor roJects ection li l/9/
at gne Summary:
Ins ection from A ril 28 throu h June 7, 1991 Re ort Nos. 50-275/91-13 and 50-323/90-13 A~d:
Th i
i i 1dd i
i i
f operations, maintenance and surveillance activities, follow-up of onsite events, open items, and licensee event reports (LERs),
as well as selected independent inspection activities.
Inspection Procedures 61726, 62703, 71707, 71710, 90712, 92700, 92701, and 93702 were used as guidance during this inspection.
S~afet
- Issues Mana ament S stem SINS) Items:
None Results:
General Conclusions on Stren th and Weaknesses:
The licensee demonstrated an increasing awareness of t e potential for safety benefits by careful attention to risk evaluation in the preventative maintenance area.
Specifically as noted in section 5 of this report, the licensee recognized two instances where the rescheduling of preventative maintenance 9107290059 9107 PDR ADQCK 05000275
would not add risk but would increase equipment availability.
The licensee committed to establish a written policy,in this area.
As indicated in paragraph 9a, the licensee's followup of corrective actions for lack of control of work activities in the spent fuel pool in early 1990 was not effective.
The issue was identified in an inspection report cover letter and PGSE responded in writing to this concern.
The matter was also the subject of a nonconformance report which was closed after review by onsite and offsite review committees.
However, the same lack of,control of work associated with the refueling equipment was demonstrated in the 1991 refueling outage.
Repairs were made to a
refueling tool without work instructions, were not successful, and resulted in additional loose parts in the spent fuel pool.
The repairs were made by Westinghouse contract personnel under the observation of-controlling PGSE engineers in both 1990 and 1991.
Si nificant Safet Matters:
None.
Summar of Violations and Deviations:
None 0 en Items Summar
Eight items were closed, one item was opened and two items were examine but left open due to remaining licensee action '
DETAILS Persons Contacted J.
D. Townsend, Vice President, Diablo Canyon Operations 5 'Plant Manager
- D. B. Miklush, Manager, Operations Services
- N. J. Angus, Manager, Technical Services
- B. W. Giffin, Manager, Maintenance Services
- D. H. Oatley, Manager, Support Services
- W. D. Barkhuff, guality Control Manager
- R. P.
Powers, Mechanical Maintenance Manager D. A. Taggert, Director guality Support T. L. Grebel, Regulatory Compliance Supervisor H. J. Phillips, Electrical Maintenance Nanager-J.
S. Bard, Planning Manager W. G. Crockett, Instrumentation and Controls Manager J. A. Shoulders, Onsite Project Engineering Group Manager M. G. Burgess, System Engineering Manager
- S. R. Fridley, Operations Manager
- R.
Gray, Radiation Protection Manager The inspectors interviewed several other licensee employees including shift foremen (SFM), reactor and auxiliary operators, maintenance personnel, plant technicians and engineers, quality assurance personnel and general construction/startup personnel.
"Denotes those attending the exit interview.
2.
0 erational Status of Diablo Can on Units 1 and
Unit 1 began the reporting period in power ascension from the completed refueling outage.
The unit achieved full power at the end of April but reduced power to 50% in May to repair a weld leak on main feed pump 1-2 balancing line.
After its return to full power, Unit 1 experienced a
reactor tr ip on Nay 17, 1991, due to an ISC technician error during surveillance testing.
The unit returned to full power following the event and remained at full power for the remainder of the reporting period.
Unit 2 began the reporting period at full power and remained at power for the entire reporting period.
On June ll, 1991, just after the reporting period ended Unit 2 achieved a record run of 400 days at power.
During the report period the site was visited on separate occasions by NRC Commissioner Remmick, and an ACRS member, J. Carroll.
In addition, an NRC team inspection was conducted focusing on electrical distribution systems.
Other safety inspections during the report period included a
NRR vendor branch examination of procurement practices, operator licensing examinations, a security inspection, a
NRR human factors examination of personnel involved in the Unit 1 reactor trip, and an emergency preparedness inspection.
In addition, a management meeting was held at the NRC, Region V, Walnut Creek office on Nay 28,.1991 and a
guality Assurance meeting was held at the NRC, Region V office on
May 29, 1991.
Site visits were conducted by various NRC management personnel during the report period to attend exit interviews and provide management overview of inspection activities.
Site visits we~ conducted by NRC, Region V, J.
B. Martin, J.
Reese, L. Miller, D, Kirsch, and R.
P.
Zimmerman, and the Office of Nuclear Reactor Regulation, J.
Dyer and M. Virgilio.
3.
0 erational Safet Verification (71707)
General b.
During the inspection period, the inspectors observed and examined activities to verify the operational safety of the licensee's facility.
The observations and examinations of those activities were conducted on a daily, weekly or monthly basis.
On a dai.ly basis, the inspectors observed control room activities to verify compliance with selected Limiting Conditions for Operations (LCOs)
as prescribed in the facility Technical Specifications (TS).
Logs, instrumentation, recorder traces, and other operational records were examined to obtain information on plant conditions and
'o eveluate trends.
This operational information was then evaluated to determine if regulatory requirements were satisfied.
Shift turnovers were observed on a sample basis to verify that all pertinent information of plant status was relayed to the oncoming crew.
During each week, the inspectors toured the accessible areas of the facility to observe the following:
(a)
General plant and equipment conditions.
(b)
Fire hazards and fire fighting equipment.
(c)
Conduct of selected activities for compliance with the licensee's administrative controls and approved procedures.
{d)
Interiors of electrical and control panels.
(e)
Plant housekeeping and cleanliness.
{f)
Engineered safety feature equipment alignment and conditions.
(g)
Storage of pressurized gas bottles.
The inspectors talked with operators in the control room, and other plant personnel.
The discussions centered on pertinent topics of general plant conditions, procedures, security, training, and other aspects of the work activities.
Radiolo ical Protection The inspectors periodically observed radiological protection practices to determine whether the licensee's program was being implemented in conformance with facility policies and procedures and in compliance with regulatory requirements.
The inspectors verified that health physics supervisors and professionals conducted frequent
C.
plant tours to observe activities in progress and were aware of significant plant activities, particularly those related to radiological conditions and/or challenges.
ALARA consideration were found to be an integral part of each RMP (Radiation Work Permit).
Ph sical Securit (71707 Security activities were observed -for conformance with regulatory requirements, implementation of the site security plan, and administrative procedures including vehicle and personnel access screening, personnel badging, site security force manning, compensatory measures, and protected and vital ar ea integrity.
Exterior lighting was checked during backshift inspections.
No violations or deviations were identified.
4.
Onsite Event Follow-u 93702 Visit b Commissioner Remmick i
b.
On April 29, 1991, Commissioner Forrest J.
Remmick visited the site accompanied by Regional Administrator John.
B. Martin.
The Commissioner toured the site and met with plant management.
Visit b a Member of Advisor Committee of Reactor Safe uards (ACRS)
On May 2, 1991, Mr. J. Carroll, a site member of the ACRS, visited the site.
C.
NRC Team Ins ection d.
On May 6, 1991, an NRC team inspection commenced.
The focus of the team inspection was Electrical Distribution System Functional Inspection (EDSFI).
During the inspection, team member s observed many plant maintenance and surveillance activities in conjunction with their examination of electrical design.
Unit 1 Reactor Tri and Safet In'ection On May 17, 1991, a Unit 1 reactor trip from 100% power occurred due to personnel error.
An instrument fuse for Nuclear Instrumentation
.
Channel N42 was inadvertently removed by an Instrumentation and Controls ( ISC) technician while at the same time a surveillance test procedure (incore/excore calibration)
was being performed on Channel N41.
The removal of the fuse tripped a second channel of power range instrumentation providing two out of four coincidence for a high flux reactor trip.
Steam dump valves to the condenser opened as designed, but two valves failed full open (due to failure of the valve stem) which caused excessive cooldown of the reactor coolant system.
The cooldown resulted in lowered system pressure and a consequent safety
'njection one minute after the tri The licensee declared an unusual event and made the proper one hour non-emergency report.
Operator actions in this event were judged to be adequate.
The operators quickly diagnosed the problem and shut the main steam isolation valves to terminate the cooldown.
The operators were. familiar with several previous events involving failed steam dumps and reactor cooldown events.
The licensee has issued Licensee Event Report (LER) 50-275/91-09 on the event.
The LER describes the event in greater detail and provides a safety analysis as well as describing corrective actions.
The licensee's LER is adequate and is considered closed.
The licensee stated in the LER that corrective actions for the steam dumps would be addressed in a revision to LER 50-275/90-07.
The reactor trip and licensee actions prior to restat t were discussed in detail with the licensee and with NRC management.
Mana ement Meetin On May 28, 1991, a management meeting was held in the Walnut Creek offices of the NRC Region V.
The topics of discussion were the steam dump valve failure history and licensee's event investigation results from the March 7, 1991, loss of offsite power event.
This meeting was followed by a Quality Assurance (QA) meeting on May 29, 1991 to discuss PGIIE QA programs and initiatives.
Chlorine Monitors La sed On May 28, 1991, all gaseous chlorine was removed from the site, except for minor amounts.
The licensee will perform future chlorinations with hypochlorite solutions.
Consequently, the licensee's chlorine monitors were allowed to lapse in their period calibration and became inoperable by definition.
The technical specification for chlorine monitors was considered nonapplicable since the technical specification says it is applicable whenever gaseous chlorine is on site.
Feedwater Control Valve Problems On June 4, 1991, Unit 1 feedwater regulating valve FCV-540 was causing flow oscillations.
Physical examination showed the valve stem to be opening and closing with a rapid partial stroke movement.
The licensee fully opened feedwater bypass valve FCV-1540 which smoothed out the operation of FCV-540.
The licensee has investigated this phenomenon before specifically on FCV-530 on Unit 2.
The valve was examined and repaired with Unit 2 at 15% power.
Unit 1 remains at lOOX.
Valve FCV-1540, the bypass, can remain full open for 12 months per licensee calculations.
At the end of the
months the erosion/corrosion of the bypass valve piping will reduce to minimum wall.
The licensee intends to examine FCV-540 if it becomes available before that tim A
No violations or deviations were identified.
5.
Maintenance 62703)
The inspectors observed portions of, and rev'iewed records on, selected maintenance activities to assure compliance with approved procedures, technical specifications, and appropriate industry codes and standards.
Furthermore, the inspectors verified maintenance activities were performed by qualified personnel, in accordance with fire protection and housekeeping controls, and replacement parts were appropriately certified.
a.
Diesel Generator Maintenance The inspector observed maintenance on diesel generator 1-3.
Tightening of leaking cylinder head petcocks was observed subsequent to a hot gas leak which occurred during a post maintenance test.
b.
Preventative Maintenance Risk Balancin On June 5, '1991, during the morning planning meeting, the operations services manager questioned the planned preventative maintenance for diesel generator 1-3.
The diesel generator had full maintenance completed just two months prior, during the Unit 1 outage.
,A meeting was held with appropriate personnel from scheduling and preventive maintenance and it was agreed that the preventative maintenance should have been done earlier and the periodicity rescheduled.
This matter was discussed with the plant manager.
The plant manager stated that there was no written policy regarding balancing the risk of defering preventative maintenance with equipment out of service time.
The plant manager stated that such a written policy would be issued in the future.
The inspectors wi3 l followup this issue (Followup Item 50-572/91-13-01).
It was noted after the close of the report period, that preventative maintenance of Unit 2 coolant charging pump 2-2 was deferred from June 1991 to September 1991 (the next refueling outage).
Although the motivation for this rescheduling was not driven by risk assessment but rather by work load impact, the rescheduling does demonstrate that safety improvements are available to b'e taken advantage of if the licensee focuses on this area.
This was discussed with the licensee at the exit interview.
c ~
~RO S
On June 6, 1991, the licensee determined that the revised internals for the main steam dump valves (SDVs) were not of the proper configuration.
, Specifically, the cutouts on the plug cages were not cut to the
proper shape and consequently would not pass the design flow if put'n service.
This was the second major problem with spare parts configuration of SDVs from the manufacturer.
The previous known occurrence had to do with thread tolerances and resulted in failed parts '(stem separation at the threaded connection).
The inspector examined the licensee's receipt inspection process.
The process meets regulatory requirements but would not identify improperly sized parts because par t dimensions are not checked.
Although the condenser steam dumps are not safety related, there are similiar safety related valves used as the atmospheric steam dumps.
Those valves are manufactured by the same vendor, but are a different model number and size.'he
.-licensee commenced dimensional checks of the condenser steam dump spare parts immediately after this discovery and is considering future dimensional checks for all parts from this vendor.
No violations or deviations were identified.
6.
Survei ll ance 61726 By direct observation and record review of selected surveillance testing, the inspectors assured compliance with TS requirements and plant procedures.
The inspectors verified that test equipment was calibrated, and acceptance criteria were met or appropriately dispositioned.
a.
Steam Dum Testin The inspector observed special testing of Unit 1 steam dump valve PCV-6.
The licensee's Plant Safety Review Committee (PSRC)
approved a temporary procedure TP-TD-9103 which tests the valve with internals similar to those which failed in the Nay 17, 1991, event.
The procedure also re-performs the test after internals are replaced with new improved internals.
The test is done at reduced power.
The tests were well coordinated, well run, well documented, and had a great deal of management attention.
The results of the test did not demonstrate any surprising results but did demonstrate a lack of effect from condensed water in the dump valve (which was an open concern of the licensee's).
The test demonstrated satisfactory operation of the new improved internals on June 10, 1991.
No violations or deviations were identified.
7.
En ineerin Safet~Featnre Verification 71710)
'he inspector wa 1 ked down access ible portions of the Unit 1 Auxi 1 iary Building Ventilation System and examined control room switch lineups and annunicatio No violations or deviations were identified.
8.
Licensee Event Re ort Follow-u 92700 a ~
Status of LERs The LERs identified below were also closed out after review by the inspectors:
Unit 1:
83-38, 90-12, 91-09 Unit 2:
90-08, 90-09 No violations or deviations were identified.
9.
, 0 en a ~
Item Follow-u 92703, 92702)
Lack of Control on the Fuel Handlin Buildin Brid e Crane, Unreso ved Item 50- 23/90-08-02 en This inspection report unresolved item from early 1990 dealt with refueling outage problems on the refueling bridge crane.
The item described licensee problems in the areas of:
Modification Testin
Modifications to the crane were performed but not teste su resent to identify new problems created by the changes.
'1 Hardware Problems:
The crane hoist coasted 4 1/2 inches
~yg.
111 111
1 pp p
yy Procedures:
Procedures were not followed by contractor personnel when moving fuel.
Fast speed was used vice slow speed.
Hardware Set pints:
Hardware setpoints (limit settings)
were changed by Fse personneT without a procedure change and without a work order.
ualit Assurance ( A) Audits:
gA audits of these fuel handling operations did not identify any of the problems described above.
In accordance with their commitment to the NRC a nonconformance was issued on this matter DC-2-90-TN-N046, Revision 0.
This was an important nonconformance.
As a consequence of the lack of controls, a fuel assembly was stuck, suspended from the crane, for seven hour s before crane controls wer e corrected and the assembly placed in a stable location.
The licensee's corrective actions included ( 1) revise the procedure (STP N-27, "Fuel Handling System Interlock Verification") to verify the fuel assembly can be lifted high enough, (2) change the control setpoint to prevent the crane from getting stuck, (3) maintenance check the brakes and switches, and (4) revise the operations department procedure to require the crane problems be. identified to the senior reactor operator and
"management" (the plant production engineer was considered management for this purpose).
These corrective actions addressed hardware items but did not address modification testing, following procedures, the need for a work order, and why the'A audit did not identify these problems.
The plant safety review committee (PSRC)
reviewed the completed"NCR
'on 'November 14, 1990, and the NCR was sent to the General'Office Nuclear Plant Review and Audit Committee (GONPRAC) on November 15, 1990, and reviewed thereafter.
The nonconformance report actions were signed off as completeby the NCR technical review group chairman on February 12, 1991 and were verified closed on March 19, 1991, by gA.
The inspector noted that the nonconformance report had been closed before the Unit 1 refueling outage in 1991.
It appears that not dealing with procedural adherence resulted in a problem with refueling work in the Unit 1 outage.
Specifically, a lost pin on a fuel handling'ool was repaired using Unit 2 pat ts without a work order.
The repair was not successful and the new pin fell into the refueling cavity; Although the pin was recovered'nd this issue was identified by gA (reference audit finding gE f0008682), the involvement of Westinghouse contract personnel, who were being observed by the reactor engineer (PPE), indicate that few lessons were learned by those involved in the 1990 events.
At the exit interview, the licensee was reminded that this particular open item was questioned in Inspection Report 50-275/90-08 cover
'letter and that the licensee responded specifically to the finding in PGSE letter DCL 90-162 of tune 25, 1990.
That letter agreed that a more thorough investigation and followup of such problems should be conducted.
At the exit interview the inspector explained his concern that the actions taken in the nonconformance did not address the weaknesses indicated in testing, procedure adherence and gA audit.
The licensee committed to reexamine these apparent weaknesses.
This unresolved item remains open.
Auxiliar Feedwater Pum Overs eed Tri
, Enforcement'tem 50-323/90-12-01 C osed This violation dealt with the overspeed trip of the Unit 2 auxiliary feedwater pump on April 24, 1990.
The initial licensee analysis concluded that improper venting caused the overspeed.
Subsequent analysis by the licensee indicated a water slug in the steam line was the cause of the overspeed.
The nonconformance report concludes that design of the steam traps causes the problem for the specific situation where the condenser is not available and the main steam isolation valves are closed.
Although this appears to be a. problem
.only in a post outage'eturn-to-service situation, the licensee's nonconformance does not say s'o.
The nonconformance concludes that an engineering work request would be written provide modifications to the steam traps.
The licensee's nonconformance was considered complete and was signed off by the TRG chairman on May 17, 1991.
Although the nonconformance closure appeared to be premature, the inspector discussed the closure at the exit interview and it was determined that design changes had been issued.
The work was complete on Unit 1 and scheduled for Unit 2.
Therefore this item is closed.
c.
Failure to Follow Work Order, Enforcement Item 50-323/90-13-02 C ose This item is closed based on the licensee's actions.
d.
Im roved Over si ht of Corrective Action Pro ram Followu Item 50-275 90-01-03 C ose e.
This item is closed based on licensee commitments at management meetings and resultant actions such as problem tracking at the plant managers meetings.
Assessment of Plant Oe radation, Followu Item 50-323/89-21-05 en This item originally dealt with corrosion of. outdoor components.
Subsequently, problems such as intake concrete spalling and reinforcing bar corrosion have been identified.
The licensee plant manager requested a detailed plan from his maintenance staff on Nay 1, 1991, to address these plant aging issues.
The plant staff has been working on such a plan.
At the exit interview, the inspector suggested that plant management may want to complete their plan and present it, as the issue is now two years old.
Licensee management stated they would consider this.
10.
Unresolved Items Unresolved. items are matters about which more information is required in order to ascertain whether they are acceptable items, violations, or deviations.
An unresolved item disclosed during this inspection is discussed in paragraph 9a of this report.
ll.
Exit (30703 On June 27, 1991, 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 l