IR 05000275/1991020
| ML16342B819 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/19/1991 |
| From: | Morrill P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML16341G267 | List: |
| References | |
| 50-275-91-20, 50-323-91-20, NUDOCS 9109110243 | |
| Download: ML16342B819 (30) | |
Text
'
U. S.
NUCLEAR REGULATORY COMMiISSION REGION V
Report Nos:
50-275/91-20 and 50-323/91-20 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:
June 8 through July 22, 1991 Inspector:
P.
P. Narbut, Senior Resident In pector Approved by:
P. J.
orrs
,
Ghee
, Reactor rogects Section
Date Signed Summary:
I Ins ection from June 8 throu h Jul 22, 1991 Re ort Nos. 50-275/91-20-3 3 91-20 Areas Ins ected:
The inspection included routine inspections of plant 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, 90712, 92700, 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:
The licensee demonstrated a keen sensitivity to risk assessment during the report period.
The advisability of performing pre-outage on-line calibrations of protection set instrumentation was discussed, elevated and finally assessed at the plant manager level before implementation.
This cautious assessment is viewed as a strength.
The licensee demonstrated quick initial responses to an ammonia spill and to the discovery of potentially degraded equipment such as a blocked spring can and cracked ventilation ducting.
These quick coordinated responses are viewed as a licensee strength.
9109220243 92082 PDR ADOCK 05000275 G
An increased number of errors occurred due to work clearances and surveillance testing.
Although none of the errors resulted in matters of great safety significance, the number indicates the need for management attention.
Mork clearance, problems included a boron.injection tank dilution (within technical specification limits; paragraph 4.f.),
a monitored but unplanned release from a gaseous decay tank (paragraph 4.n.),
a failure to follow operations policy which caused a jammed closed valve for the auxiliary feedwater pump (paragraph 4.c.),
and increased out-of-service time for the component cooling water heat exchanger due to the poor sequence of the clearance (paragraph 4.c.).
Surveillance Test problems involving operations included actuating the wrong relay which started the wrong train of safety related equipment (paragraph 4.o.),
and isolating the backup air to the 105 Steam Dump Valves during air bottle switching (paragraph 4.t.).
,Several of the above problems involved the maintenance operations interface and.- require attention by both departments.
Likewise, an additional surveillance missed by operations (for diesel fuel oil sampling)
was caused by plant engineering personnel not updating a
computerized recurring task scheduler.
V Si nificant Safet Matters:
None.
Summar of Violations and Deviations:
None.
0 en Items Summar
Three items were opened, none were close DETAILS Persons Contacted J.
D. Townsend, Vice President, Nuclear Power Generation
& Plant Manager Diablo Canyon Power Plant D. B. Miklush, Manager, Operations Services
"M. J. Angus, Manager, Technical Services
- B. W. Giffin, Manager, Maintenance Services W.
G. Crockett, Instrumentation and Controls Director
- D. H. Oatley, Manager, Support, Services W. D. Barkhuff, equality Control Director R.
Powers, Mechanical Maintenance Director D. A. Taggert, Director guality Support T. L. Grebel, Regulatory Compliance Supervisor H. J. Phillips, Electrical Maintenance Director J.
S. Bard, Work Planning Director J; A. Shoulders, Onsite Project Engineering Group Manager M. G. Burgess, System Engineering Director
- S. R. Fridley, Operations Director R.
Gray, Radiation Protection Director
- D. K. Cosgrove, Leak guality Control Specialist
- J. J. Griffin, Senior Engineer Regulatory Compliance
- R. W. Hess, Assistant Onsite Project Engineer
- R. P. Flohaug, Senior {}ualityAssurance Supervisor
- J. B. Hock, Manager, Nuclear Safety and Regulatory Affairs 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 on August 8, 1991.
0 erational Status of Diablo Can on Units 1 and
Both units began the reporting period at 100$ power and maintained essentially full power operations for the entire reporting period.
Brief reductions to 80% were performed for testing.
No reactor trips were incurred.
One 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> non-emergency report was issued regarding the inadvertent start of safety equipment during testing due to the improper actuation of a relay.
The most notable occurrence during the period was the discovery by operators that non-safety related Unit 1 containment ventilation ducts were cracking since the Unit 1 restart in April 1991.
Despite the fairly large holes developing in the ducting, this occurrence has little safety significanc.
0 erational Safet Verification 71707 a.
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 daily 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 to evaluate trends.
This operational information was then evaluated to determine if'regulatory requirements were satisfied.
Shift turnovers were observed on a sample basis to veri,fy 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 l.icensee'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 periodical)y 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 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 was found to be an integral part of each RWP (Radiation Mork Permit).
C ~
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 area integrity.
Exterior lighting was checked during backshift inspections.
No violations or deviations were identified.
4.
Onsite Event Follow-u 93702 a ~
False Indications of Reactor Coolant S stem Leaka e
b.
On June 11, 1991, operators noted that Unit 2 had apparent reactor coolant leakage of about 0.4 gpm with an increasing trend.
This reading was based on sump integrator readings.
Containment entry was made but nothing was found.
Later on June 13, 1991, water was found issuing from the locked door entrance to the reactor cavity sump room in the containment.
The resident inspector, a visiting radiological protection inspector, and Branch Chief attended the licensee's briefing for operations and radiological protection personnel.
An entry was planned into the high radiation area to assess the source of water.
The inspector requested, that they also visually observe whether the reactor cavity had accumulated water, since flooding of the cavity has occurred at other sites.
Although the cavity sump pump is in a curbed area and water should not be able to cross the curb and enter the cavity depression, licensee management agreed that a visual verification was prudent.
The briefing of personnel conducted by licensee management and on-shift supervision was professional and cautious.
Pers'onnel entered, verified that the cavity was dry, and noted that the source of water was a leaking valve bonnet on the cavity pump discharge valve downstream of the flow integrator.
The leaking valve was repaired a few weeks later.
Batter Grounds On June 11, 1991, a battery ground appeared on vital battery 1-1.
Initial investigation that day did not lead to the discovery of the source of the ground.
Later in the month, the ground showed up simultaneously in batteries 1-3 and 1-1 during fire alarm testing.
The resident inspector referred this anomaly to a visiting NRC electrical inspector.
The problem was traced to a design change wiring error which effectively crosstied two vital OC buses.
The buses were separated by their respective breakers but the adequacy of breakers alone (as separation)
was questioned and will be pursued by the NRC electrical inspector.
Inspection Report 50-275/91-11 contains further detail Work Clearance Errors On June 11, 1991, operators made two minor errors.
The first error involved the Component Cooling Water Heat Exchanger 2-1, which had to be mechanically cleaned twice because the inlet isolation valve had not been fully shut during the first, cleaning.
This partially open valve allowed marine debris to fall backward in the inlet pipe.
On restart of the pumps after cleaning, the hidden debris immediately clogged the heat exchanger again requiring re-cleaning.
This had no safety impact but did increase the out of service time of the safety related heat exchanger.
The second error involved a steam supply valve for the Auxiliary Feedwater pump.
Motor operated valve FCV-38 became bound in the closed position.
The valve had been left closed and the selector switch left in the closed position.
Plant operating orders require operators to check that the switch position is neutral. before manually opening the valve.
This was not done and when the operator engaged the manual drive and started to manually open the valve the
"torque close" electrical contacts opened and caused the valve to electrically hammer closed again.
The valve wedged itself tightly closed and was later manually opened with difficulty.
The inspector reviewed an engineering evaluation of the valve's operability and reviewed the operations quality evaluation.
Licensee follow-up actions appeared to be appropriate.
Plant Air Com ressors On June ll, 1991, one of the plant air compressors for instrument air had been experiencing electrical trip failures.
The licensee had noted the problem intermittently since May 1991.
The other air compressor was beginning to show bearing vibration problems.
This put instrument air supply in jeopardy.
When the licensee maintenance and engineering personnel did not appear to be promptly addressing these problems in the early part of June, the inspector expressed concern.
The licensee maintenance personnel evaluated the problem and concluded the problem was a design issue in that, the circuit breaker trip unit was undersized.
The maintenance forces tested available trip units and replaced the unit with a unit with a higher trip rating.
The licensee planned to issue a design change to replace the air compressor trip units with the higher ranged unit.
An action request was written to request this design action.
The licensee determined that a quality evaluation was not necessary.
At the exit interview, the inspector stated his concern that the licensee should have been more aggressive in their pursuit of this problem.
The hardware correction was slow in coming and the root cause was apparently not determine Ammonia S ill On June ll, 1991, operators were assisting a vendor fill the anhydrous ammonia tanks when an apparent spill occurred.
The anhydrous ammonia is used for secondary plant chemistry control.
The "spill" was noted by personnel in the turbine building who smelled ammonia.
The spil,l turned out to be a ruptured diaphragm on a vacuum breaker valve located in the turbine building buttress area outside the Technical Support Center (TSC).
The filling of the tank displaced ammonia fumes which were forced out of the. ruptured diaphragm.
The inspector examined the potential habitability issue with the TSC and concluded that ammonia fumes are a possibility during tank filling with a ruptured diaphragm.
However, tank filling is not likely to occur during an event with the TSC manned.
Licensee response to the ammonia incident was quick and conservative.
Plant personnel were warned over the PA system.
Licensee operations and safety personnel corded off the area,
.donned respiratory gear, provided ventilation, and took samples until the area was clear.
The effective response by safety personnel was discussed at the exit interview.
In action requests prepared as a result of the occurrence, licensee personnel suggested that the valve diaphragm should have been in a preventative maintenance program because the diaphragm may require periodic replacement.
The licensee initiated an action request to include this valve diaphragm preventative maintenance.
In the quality evaluation the root cause of the failure was determined by the licensee to be indeterminate.
Work order entries by mechanics indicated that certain tie rods had broken.
The inspector urged the licensee to consider the need for a better evaluation of the cause of the problem.
Valve Lineu Error in Unit 2 On June 13, 1991, a valve lineup error almost caused a technical specification violation by diluting the Boron Injection Tank (BIT).
Subsequent sampling showed the tank was not significantly diluted.
The problem was caused by the work clearance paperwork prepared for a heat trace repair job.
The clearance opened valve CVCS-2-8458B to provide flow through the line (to keep it warm).
However, in effect, this action crosstied transfer pumps which eventually caused dilution of the BIT.
Specifically, later when pure water was being added to the storage tank, this action caused pure water to be sent to other places as well, including the BIT.
The problem was noted early, due to level changes that should not have occurred.
BIT sampling was performed and concentrations were found to be satisfactory.
The operations manager took prompt action and wrote a quality evaluation which will define action to prevent recurrenc Crackin of Non-Safet Related Ventilation Ductin in Containment nest On June 18, 1991, during the weekly Unit 1 containment entry an operator found significant duct cracking and. several missing pieces of duct (up to 18 inches in diameter).
The ducting has apparently cracked after the Unit 1 restart from refueling in April 1991, and did not have a prior history of cracking 'before that outage.
The containment fan cooler units which supply the ducts had been'leaned during the outage and airflow had increased.
Operators reported the subsequent vibration of the duct work to be severe.
Entries into containment were made by engineering and metallurgical personnel to assess the situation.
During the evening of June 18, 1991, a plant meeting chaired by the Operations Manager, including design and plant engineers, assessed the condition as"not affecting operability based on the ability of the fan coolers to cool the containment.
The inspector, at the meeting, observed the determination to be narrow since the FSAR describes a hydrogen mixing function for the system as well as a
cooling function.
The Plant Technical Services Manager committed to a full and formal operability study.
The operability evaluation was done over the next few days and an operability evaluation document (OE 91-02RO)
was issued on June 21, 1991'.
The licensee's operability determination and actions were discussed at length with regional and NRC headquarters management and technical personnel.
It was concluded that the duct conditions were acceptable based on lack of safety significance.
The area of ducting involved did not serve a safety function and would not impact the function of safety related equipment.
At the end of the reporting period, the licensee was making weekly re-inspections.
Holes had been drilled at the end of the cracks.
This action arrested most cracks but'racks continued to form and were observed to grow several inches per week.
The licensee has prepared a design change to repair the duct and reduce vibrations while the plant is at power.
The licensee has not yet completed a root cause analysis on the cause of the duct cracking nor were the ducts instrumented.
However, licensee engineering personnel were working on a root cause analysis study and have decided that instrumentation is not necessary.
The inspector will continue to follow licensee progress on this matter.
Ino erable Fire Dam er On June 20, 1991, during performance of fire damper testing, a fire damper'in the cable spreading room failed to close.
The cause was
the improper installation of a "S" hook on the fusible link assembly holding'he damper open.
The "S" hook was installed backwards and caught on the damper after the fusible link released.
This occurrence was similar to 1989 occurrences in the control room which were the subject of a reportable event which had corrective action to inspect all other "S" hook installations.
Discussions with the safety manager indicate that the consequence of this event was reduced by the fact that the failed damper was one of two redundant dampers.
The original actions to inspect
"S" hooks had been applied only to vertical dampers.
This occurrence involved a horizontal damper.
The licensee initiated an immediate re-inspection of all dampers and included this occurrence in a nonconformance report.
The inspector will follow licensee actions through the nonconformance report.
Steam Dum Valve Re air During June 1991, all Unit 1 condenser steam dump valves were modified and new internals installed to preclude breaking due to microwelding.
The licensee intends to replace Unit 2 steam dump valve internals in July as parts are made available.
Unit 2 Char in Pum on Alert Unit 2 charging pump 2-2 was classified as being on alert status (ASME section XI) when one of its motor bearings doubled in vibration level compared to baseline.
Licensee personnel theorized that tightening balancing bolts would alleviate this condition.
The licensee tightened the bolts and performed another test 3 days later after performing an analysis to justify an increased vibration acceptance level.
Ultimately the licensee justified acceptance of potentially increased vibration levels using vendor information.
Acceptance by engineering analysis is allowed by ASME Section XI.
On retest however, the vibration levels had been reduced.
The licensee's position on this matter was that they believed tightening the balancing bolts would not affect vibration negatively and therefore did not require retest.
The licensee re-performed vibration testing on the date required by the accelerated ASME schedule.
The inspector agreed with the licensee's assessment.
Feedwater Re ulatin Valves.
In June 1991, the main feedwater regulating valves on Unit 1 and Unit 2 were in a variety of configurations due to separate problem The normal configuration with the digital feedwater control system would be to have all four main Feedwater Regulating Valves and all four main Feedwater Regulator Bypass Valves open and in automatic control.
Erosion/corrosion concerns have dictated that the licensee run with the bypass valves closed.
Otherwise the bypass piping wil,l experience thinning and will eventually require replacement.
Both units have sufficient wall thickness to allow continued operation until the next outage opportunity.
With the bypass valves closed the main Feedwater Regulating Valves are more open and are apparently outside their optimum regulating range.
Consequently, some of the.main feedwater valves oscillate or vibrate.
The licensee has reopened some bypass valves for control and put the associated main valve in manual to stop the oscillation.
Current Unit 1 Main Feedwater Regulating Valve Status:
Steam Lead Main Valve B
ass Valve
1-FCV 510 Open in Manual FCV 1510 Open E Controlling
1-FCV 520 Open and Controlling FCV 1520 Closed
1-FCV 530 Open and Controlling FCV 1530 Closed
1-FCV 540 Open in Manual FCV 1540 Open 8 Controlling Current Unit 2 Main Feedwater Regulating Valve Status:
Steam Lead Main Valve B
ass Valve
2-FCV 510 Open and Controlling Closed
2-FCV 520 Open in Manual Open and Controlling
2-FCV 530* Open and Controlling Closed
2-FCV 540 Open and Controlling Closed The inspector discussed the situation with cognizant licensee engineers.
General Office engineers stated they are preparing a
plan and gathering data to understand the phenomenon being experienced.
A task force including plant maintenance-and operations had been formed.
The inspector noted the safety function of the valves are to shut and there have been no indications that this'unction is compromised by the current conditions.
- After the report period on July 24, 1991, Unit 2 FCV 530 began to exhibit the same oscillation/vibration.
The licensee placed the valve in manual in addition to the others.
The inspector will continue to followup licensee action-on this matter.
At the exit interview, the inspector noted corporate
engineering involvement in the resolution of this problem and encouraged such participation.
Steam Tra s Underrated During June 1991, through discussions with engineers, the inspector became aware that steam traps throughout the plant were originally purchased and installed for 600 psi service although no load steam pressure is about 1000 psi.
A 1983 design change accepted the traps as adequate for-the applied pressure from a pressure boundary standpoint.
The traps apparently have a shortened serviceability life however and have been the source of plant efficiency losses to the licensee.
The licensee plans to replace the traps in future outages to avoid steam losses.
This replacement will also help the auxiliary feedwater room steaming problems encountered in previous years.
S rin Can Blockin On June 27, 1991, the inspector attended a meeting regarding potentially blocked spring can hangers on the Unit 1 pressurizer surge line.
THis was of concern due to the potential for inducing extreme stress in the piping.
The potential for the problem was identified by licensee inservice inspection record review and closeout.
Their records showed these spring cans to have been blocked but no record could be found to show that they were unblocked.
Containment entry was carefully planned and was done that evening.
The spring cans were found not to be blocked.
The licensee properly identified issues regarding work control since the spring cans had been blocked and unblocked during the last outage apparently without a work order.
The licensee has generated a guality Evaluation and is pursuing root cause and corrective action.
Un lanned Monitored Release from Gas Deca Tank On June 29, 1991, the inspector was notified of an unplanned release from the Maste Gas System.
The waste gas vent header had decayed from 1.7 psig to 0.5 psig and Gas Decay Tank 1-2 decayed from 50 psig to 18 psig over a period of several hours.
The release was monitored through the plant vent, was minor, and met requirements had it been a planned release.
The release was from a moisture separator level indicator drain valve (GW-0-16) which was found open.
The licensee was pursuing full understanding, but it initially appeared that maintenance personnel working the level indicator had opened and shut the valve and inadvertently left it open, at the completion of work, because of the fai lure to implement necessary clearance controls by operation In addition, the operations mana'ger considered that his auxiliary operator personnel, who.monitor the Waste Gas System, were remiss in not reacting properly to the pressure decrease sooner than they did.
The licensee wrote a quality'valuation report on the matter but as of July 24, 1991, had not recorded.root ca'uses or corrective actions.
At the exit, the licensee was urged to complete this evaluation.
Re ortable Event - Inadvertent Start of En ineered Safet Feature
~Eui ment On July 5, 1991, while performing surveillance testing of the Solid State Protection System (SSPS)
an operator mistakenly actuated the wrong train's relay which started engineered safety feature equipment.
The licensee is preparing an.event report on this matter and their actions will be followed, up through the LER process.
At the exit interview, the inspector discussed the apparent growing number of operator errors and noted that attention may be warranted.
The inspector also noted that the operations manager had issued the nonconformance report analysis of the event on July 9, 1991, four days after the event.
The analysis and corrective actions were well written, clear and issued quickly.
The licensee was encouraged to continue such timely. performance.
Fire 8ri ade Nannin On July 5, 1991, and again on July 15, 1991, the inspector examined fire brigade manning at Diablo Canyon.
At,Diablo Canyon fire brigade members are part of the operations crew.
The fire brigade leader is ordinarily a licensed:operator.
NRC guidance documents and the licensee's FSAR indicate that the fire brigade should be guided by a person knowledgeable of plant systems, usually a
licensed operator.
On the morning of July 5, the licensed operator who was qualified as fire brigade leader was absent due to sickness.
The shift foreman determined that the only available fire brigade leader, as determined by the licensee's list of qualified fire brigade leaders, was a non-licensed auxiliary operator serving as the assistant control operator.
Licensee administrative procedures do not specifically require a licensed operator for the position.
The shift foreman and shift supervisor decided to assign a non-licensed operator who was on the qualified fire brigade leader list to serve as the fire b'rigade leader and to assign a senior licensed-operator to assist him should a fire event occur.
Furthermore, the licensed senior control operator should have been on the qualified list, but was not, due to a training logging problem (based on subsequent discussions with the Fire Marshall).
The non-licensed auxiliary operator was uncomfortable with the assignment and explained this to his supervision according to the shift supervisors.
The inspector called the operations shift supervisor and asked him to look into the matter.
The operations supervisor called back in a few hours and stated that it was his belief that the onshift shift supervisor had made a poor decision although an understandable one.
He further stated that the safety manager had been contacted.
The safety manager added the licensed senior control operator to the qualified fire brigade leader list.
The shift supervisor then designated the licensed senior control operator as fire brigade leader.
The licensee stated there would be followup action to clarify procedures and make them consistent.
The inspector will followup on this item including the availability of training for operators for fire brigade leader and quality assurance involvement (Followup Item 50-275/91-20-01).
Missed Surveillance Test On July 10, 1991, the licensee became aware of a missed surveillance test on diesel fuel oil testing.
The test involved verifying the
'diesel fuel inventory and verifying the absence of water.
The test should have been done by July 5, 1991, but was not due to an Engineering administrative oversight.
Engineering had not reinitialized a computerized recurring task scheduler.
This was a
repeat of at least one similar engineering oversight resulting in a missed surveillance.
I'he licensee used the recently revised Technical Specifications which allow a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> grace period to perform the missed surveillance.
The results of the surveillance test were satisfactory.
The licensee prepared a nonconformance report draft on the matter.
The inspector will followup through the nonconformance report and Generic Letter 87-09.
The licensee was determining corrective action at the end of the reporting period.
This item is considered unresolved pending identification of licensee actions (Unresolved Item 50-275/91-20-02).
Re ortable Event - Containment Ventilation Isolation CVI On July 15, 1991, Unit 2 experienced a Containment Ventilation Isolation.
The cause of the isolation was traced to an ISC technician who dropped a screw in a power supply cabinet while performing maintenance.
The screw caused a power spike in the vital AC power to the radiation detectors which actuated the CVI.
The licensee made a
4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> n'on-emergency report and wrote a
nonconformance report on the event..
The inspector will followup on the event through the nonconformance report and the Licensee Event Repor On July 16, 1991, the licensee operations department stopped planned work on the Solid State Protection System on Unit 2.
The planned
'work involved calibration of steam generator pressure, steam flow, and feedwater flow instruments.
This work is required to be done every 18 months, usually during refueling outages.
The plant has done this work before the last few outages to shorten outage time.
Performing the test at power involves tripping a protection set of bistables which puts the plant at higher risk of an inadvertent reactor trip.
However, the tripping of bistables is generally seen as putting the plant in a safer condition.
After deliberation at the plant manager level, the decision was made to proceed with the work.
At the exit interview,,the inspector emphasized the need to address the prudency of such work from a risk balance basi's.
t.
Back-u Air to Atmos heric Dum Valves Isolated On July 20, 1991, while performing daily rounds in Unit 1, an auxiliary operator discovered both backup air bottles to valve PCV-21 isolated.
PCV-21 is one of four atmospheric Steam Dump Valves which were recently included in the Technical Specifications.
The isolation apparently occurred on July 19, when one of the bottles was noted to have been depleted and was isolated and the second charged bottle was cut in.
The auxiliary operator doing the switch apparently was not aware that two valves per bottle were to be repositioned.
He had repositioned only one valve at each bottle which in effect isolated both back-up air bottles.
This matter is considered unresolved pending further review of licensee actions.
The licensee wrote a quality evaluation on the incident (Unresolved Item 50-275/91-20-03).
No violations or deviations were identified.
5.
Maintenance 62703 The inspectors observed portions of, and reviewed records on, selected maintenance activities to assure compliance with approved procedures, Technical Specifications, and appropriate industry codes and standards.
Furthermore, the inspectors ver'ified maintenance activities were performed by qualified personnel, in accordance with fire protection and housekeeping controls, and replacement parts were appropriately certified.
The inspector examined specific maintenance activities associated with Steam Dump Valve internals replacement on Units 1 and 2, ground identification on vital battery l-l, breaker repair for instrument air compressor 0-6, heat exchanger cleaning for ASW/CCW, repair of leaking
valve PCV584 near the Unit 2 reactor cavity sump pump, and containment ventilation duct degradation and repair plans.
In addition, the inspector examined work clearance problems as described in paragraph 4.
No violations or deviations were identified.
Survei 1 1 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.
The inspector examined the licensee's actions regarding followup of a Westinghouse Part 21 report on potentially shorted diodes in the Solid State Protection System electronics which could give false positive Surveillance Test results.
The licensee performed STP I-16A, testing of slave relays, on all four protection sets in both units.
The licensee found one shorted diode in one protection set on Unit 2.
The inspector observed testing of the relays in Unit 1.
ISC technicians were observed performing the regular test using the STP.
ISC maintenance engineers performed a special test recommended by Westinghouse by the Part 21 report.
In addition, the inspector examined periodic ASIDE Section NI testing of Coolant Charging Pump 2-2, fire damper testing, Solid State Protection System testing and diesel fuel oil surveillance testing.
No violations or deviations were identified.
Unresolved Items Unresolved items are matters about which more information is required in order to ascertain whether they are acceptable items, violations, or deviations.
Unresolved items disclosed during this inspection are discussed in paragraphs 4.g.
and 4.t. of this report.
Exit 30703 On August 8, 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