IR 05000275/1992016
| ML20059D059 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/24/1993 |
| From: | Johnson P NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| References | |
| OLA-2-I-MFP-137, NUDOCS 9401060375 | |
| Download: ML20059D059 (24) | |
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., ypp-/3'7 g y 93 5WIW ? U.S. NUCLEAR REGULATORY COMMISSION
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REGION V
'93 r; 23 P6 :21 ,
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Report Nos:
50-275/92-16 and 50-323/92-16 '
Docket Nos: 50-275 and 50-323 License Nos: DPR-80 and DPR-82 i
Licensee: i Pacific Gas and Electric Company '
77 Beale Street, Room 1451 San francisco, California 94106 Facility Name: Diablo Canyon Units 1 and 2 Inspection at:
Diablo Canyon Site, San Luis Obispo County, California { '
Inspection Conducted:
April 21 through June 1, 1992 Inspectors:
P. Morrill, Senior Resident inspector !
M. Miller, Resident Inspector !
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Approved by:
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P. H.[/ohnson, Chief Date Signed React 4r Projects Section 1 j Summary: !
I inspection on April 21 through June 1. 1992 (Report No /92-161 50-275/92-16 and -
l Areas Inspected:
Routine inspection of plant operations, maintenance and surveillance activities, followup of onsite events, open items, and licensee event reports Inspection (LERs), as well as selected independent inspection activitie Procedures i
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93702, and 94600 were used as guidance during this inspection.37 ,
Safety Issues Manaae nent System (SIMS1 Items: None Pesults ,
i General Conclusions on Strenoths and Weaknesses Strengths:
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A more conservative approach to the scheduling of Instrumentation and Control surveillances was note This involved a licensee initiative to
) discontinue routine use of the 25% grate period allowed by the Technical Specifications for the performance of surveillances (paragraph 6.a).
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9401060375 PDR 930824 0 ADOCM 05000275
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i Weaknesses: ..
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The NRC identified several problems which had not been identified or appropriately documented by the licensee. These included the installa-tion of plastic tarps in front of Appendix R lighting (paragraph 8.a) and
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the violations identified below.
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7 Sionificant Safety Matteri: None '
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Sumary of Violations:
i e involving the loading of two one-ton chainfalls to approxim j l pounds each wile installing a resin cask lid (paragranh 3.b(2)).
! ) nnn-cited violations were also identified, involving inconsistent Two j, ! #astener terques for two residual hest removal (RHR) syst em valves
! (paragraph 8.b) and failure to declare a Unit 2 main steam safety valve j inoperable after test equipment used to establish its setpoint was found
to have failed (paragraph 10.k).
i Open Items Sumary:
1 .nree new followup items were o
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9 were closed, I remains open. pened. Ten followup items were reviewed; J 7 closed, I remains ope Twenty LERs were reviewed; 19 were il .
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b DETAll5 Persons Contacted Pacific Cas and Electric'ComDany G. M. Rueger, Senior Vice President and General Manager, Nuclear Power Generation Business Unit J. D. Townsend, Operations Vice President and Plant Manager, Diablo Canyon W. H. Fujimoto, Vice President, Nuclear Te;hnical 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
- D. Barkhuff, Quality Control Directo *R. P. Powers, Mechanical Maintenance Director T. L. Crebel, Degulatory Compliance Supervisor H. J. Phillip
- J. A. Shoulders,Electrical Maintenance Director 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
- *R. A. Moulla, Assistant to Vice President, Diablo Canyon Operations Kohout, Safety, Health and Emergency Services Director
- D. P. Sisk, Regulatory Compliance Engineer D. R. Stermer, Power Production Engineer M. R. Tresier, Project Engineer R. Clark, Assistant Project Engineer R. Gagne, Acting Radwaste foreman U. A. Farradj, Fire Protection Engineer i R. A. Waltos, Senior Power Production Engineer S. F. Shrefler, Mechanical Maintenance Engineer B. D. Pogue, System Engineer i R. Ortega, System Engineer j R. Watson, Quality Assurance Engineer San Luis Obispo County Officials R. Hendrix, Administrator L. Williams, Deputy Administrator V. Morici, Emergency Response Coordinator ,
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- Denotes those attending the exit intervie The inspectors interviewed several other licensee em maintenance assurance personnel. personncl, plant technicians and engineers, and quality
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, Doerational Status of Diablo Canven Unit s 1 anu During April the and 25-27, inspection May 2-3,period, 1992. Unit 1 operated at 100% power, except for On April 25, Unit I reduced power to 50%
for routine condenser cleaning. While conducting maintenance on the 1-1 main feedwater pump, vacuum in the condenser was lost, causing the main turbine and the reactor to trip. Unit I was restarted on April 26 and
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was at full power on April 27.
l belo This event is described in paragraph During the period May 2-3, 1992, Unit I was curtailed to 50%
power for routine condenser cleanin Unit 2 operated at 100% power during the reporting perio . Doerat tor,a1 Safety verification (71707) General During the inspection period, the inspectors observed and examined activities to verify the operational safety of the licensee's facility. The observations and examin.tions of those activities were conducted on a daily, weekly or monthly basi On a daily basis, the inspectors observed control room activities to verify compliance with selected Limiting Conditions for Operation Logs, instrumentation, recorder traces, and other oper
records to evaluatewere examined to obtain information on plant conditions and trend to determine whether regulatory requirements were Shift utisfied.T
turnovers were observed on a sample basis to verify that all perti-nent information on plant status was relayed to the oncoming cre During each week, the inspectors toured accessible areas of the facility to observe the following:
(li General plant and equipment cond.:ons (2) Fire hazards and fire fighting equipment
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(3)
Conduct of selected activities for compliance with the licensee's administrative controls and approved procedures (4) Interiors of electrical and control panels i
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Engineered safety features equipment alignment and conditions (7) Storage of pressurized gas bottles
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The inspectors talked with control room operators and other plant personnel.
i The discussions centered on pertinent topics of general
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plant of the conditions, procedures, security, training, and other aspects work activities, i
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The inspectors also accompanied auxiliary operators during their rounds in the plant and reviewed the associated log entries. On two occasions the inspector verified that auxiliary operators were completing their rounds consistent with the log sheet entries. No instances of improper log entries were identifie Radiolocical Protection (1) The inspectors periodically observed radiological protection practices to determine whether the licensee's program was t,eing implemented in conformance with facility policies and proce-dures and in compliance with regulatorp equirements. 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 considerations were found to be an integral part t,f each RWP (Radiation Work Permit).
(2) Radioactive Waste Shipment on May 28-29. 1992
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The inspectors observed the licensee's preparation to ship a high integrity container (HIC) of radioactive resin to Ricnland, Washington for disposal. The licensee planned to survey ar.d remove the HIC from storage in a permanent plant shield cask and place the HIC in a transportation cask carried on a sole-use flatbed truck. A shielded boom crane was used for this movemen The evolution was significant in that it occurs infrequently (1 to 2 times a year at most) and the HIC had a surface dose rate of over 30 R/Hr. The inspectors observed the licensee's pre-brief meeting which covered communications, surveys, exclusion areas, ALARA considerations, trane ;perations, and contingency plan The inspectors cbserved the HIC transfer, which proceeded without incident. P w ver when placing the lid on the shipping cask, licensee per,sonnel were initially unable to get it to seat properly. The lid was supported by three slings and restrained horizontally with respect to the cask by two guide pin With the lid resting on the top of the task, the licensee's riggers replaced two of the slings with chainfall This allowed the lid to be leveled by an individual standing on top of the lid and adjusting the chainfalls. The rigger leveling the lid was shielded from the HIC by the lid itsel The lid was approximately 3 inches higher than the seated position during the evolutio seated and the rigging equipment was After several tries the lid remove During this evolution, the inspector questioned licensee personnel as to whether the chainfalls being used had adequate capacit The licensee personnel present stated that they were confident that the riggers knew what they were doing. The inspector stated that the chainfalls looked like one-ton units and the cask lid looked substantially heavie _____ _-- - - ~- -
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The next daycask the shipping May on29.the 1992, the inspector conducted a survey of truck, Radiation levels appeared to be within regulatory limits and the cask appeared to be proper-ly secured and labeled for shipment. The inspector observed that the weight of the cask lid was approximately 7300 pound The inspector discussed the chainfall capacity with the Mecha-nical used hadMaintenance been one-ton Director units. who determined that the chainfalls The licensee's quality evaluation
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found them to have a safe working load of 2000 pounds eac The load on each chainfall would have been approximately 2400 pound ' The inspector noted that this was a personnel safety issue and that the individual standing on the cask lid could have been seriously hurt if the chain had parte of Maintenance Services and Mechanical Maintenance DirectorThe M agreed that a mistake had been mad Licensee personnel stated that when the next shipment was made the correct size chain-fallswritten by wouldinstruction be available and that thei'r use would be required This is an apparent violation of Technical Specification 6.8.1 and procedures for control of rigging and load handling equipment.
i-(50-275/92-16-01)
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The inspector observed that this event involved riggers and contained elements similar to the loss of offsite power event in March 500XV 1991 which was caused by a boom crane under the Unit 1 line The Manager of Maintenance Services stated that
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the boom crane event in 1991 had been caused by personnel who were not riggers, but who had been trained to use the equip-ment.
I The inspector acknowledged that two different groups of i personnel were involved, but noted that both events appeared to ;
involve weakness rigging activities.in the preplanning and control vi lifting or ' !
Physical Security l
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Security activities were observed for conformance with regulatory requirements, the site security plan, and administrative procedures,
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including vehicle and personnel access screening, personnel ba site and security vital area force manning, compensatory measures, and protected integrit backshift inspections. y. Exterior lighting was checked during '
No violations or deviations were identified.
, ; 4 Onsite Event Followon (93702) Trio of Uni _t_1 Due to loss of Vacuum on 2 Acril 1992
! Between 9:00 p.m and 11:00 p.m. on April 24, 1992, plant operators
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decreased Unit I power to approximately 50% to allow routine cleaning of the east main condenser water boxe Main feedwater pumpvalves stop (MfP)to1-1 thewas MfPshut down and cleared to make repairs to steam turbine.
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At approximately 3:45 a.m., vacuum in the operating west condenser had degraded to an absolute pressure of approximately 4 '
The air in-leakage which degraded condenser vacuum was inches H pparentl due to leakage through the large 1-1 MFP exhaust butterfly valv : The on-shift crew attempted to stop the air in-leakage by reseating the closed 1-1 MfP exhaust valve and by placing a second air ejector in servic At 4:00 a.m., plant power was being decreased at 10 MW per minute and turbine. The decrease gland seal steam was re-established to the HFP l-1 in power appeared to be helping condenser vacuum. At 4:07 mechanical vacuum pump, plant operators attempted to place the Hash in service. When the vacuum pump suction valve from the west main condenser was opened, backpressure iricreased rapidly and at 4:08 a.m. a turbine trip and reactor trip occurre The operators subsequently stabilized the plant in accordance with Emergency Operating Procedures. All safety related equipment functioned as expecte four hour non-emergency report to the NRC.At 5:10the lice tsee made a a.m.,
The inspector event with evaluated the licensee's investigation, discussed the startu the en-shift crew, and observed the subsequent plant At approximately 1:00 p.m. on April.27, after evaluation of the event restarted Unit and correction of the cause of the trip, the licensee full power the morning of AprilThe startup was uneventful and Unit I re 28, 199 The inspector observed that the licensee's investigation into the trip identified the following information: -
After the operators had begun to reduce power at 10 MW per minute, condenser vacuum was stabilizing. The problem may have corrected itself without further actio *
Placing the Nash mechanical vacuum pump in service was consistent with the licensee's procedure AP-7, " Loss of Condenser Vacuum". l steps necessary to place the Nash pump in service,Howevel
The operators in the turbine building at the Hash pump did not i have servic a local copy of the procedure to place the pump into i
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Due to the sense of urgency the operators in the control room pump in servic did not review the procedure to place the Nash l
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Unknown to the operators, a seal' water l' solation valve for the Nash operate pump was required to be opened before the pump could properl i When the suction valve to the west condenser was opened, air entered the condenser through the Nash pump seal *
The condenser vacuum pump suction check valve appears to have 1 I
leaked sev: rely in the reverse direction, allowing air flow back to the cundense ;
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The inspector discussed the event with the Operations Director to determine the adequacy of the licenste's corrective actions. The licensee issued an incident Summary to alert other crews and added r. >
of a n feefwater pump. precautions to be taken in the procedure fo The licensee plans to inspect each unit's vacuum pump suction line check valve during outages IRS and 2R5 The licensee also plans to complete a review of all emergency d a tors might be dispatched to perform equipment' op procedure postings are plar.ned to be added based on the review.By The inspector for taking MfP questioned the adequacy of the licensee's preparation l-1 out of servic Licensee personnel stated that preparations as expecte had been adequate, but that the plant had not responded (LER) 1-92-004 This event was described in Licensee Event Report issued May 22, 199 the licensee's, review of the LE analysis of the event and corrective actions d ,
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No viola' ions or deviations were identifie .
Maintenance (62703)_
The inspectors observed portions of and reviewed records on, selected
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maintenance activities to assure com,pliance with ,
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performed by qualified personnel, in accordance with fire protection housekeeping controls, and that replacement parts were appro certifie These activities included:
Work Order No. C0096441, BATP1, Replace Mechanical Seal
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Work Order No. C0100168,10-142, Cask, Provide Support to M Concerns Raised Durino Observation of Boric Acid Transfer Pu Maintenance _
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During an observation of Work Order No C0096441, BATP1
" Rep Mechanical Seal," the inspector noted the following con,cern: lace (1)
When questioned by the inspector, the me Controlalignment optical sign-offtool of the usedalignment to ali would require removal of the lation tool. of a double dial indicator,gn the coupling, and instal-This was required because an older, slower alignment on optical alignment information. Quality Control would not rely Further review by the inspector and Mechanical Maintenance management found that Quality Control had accepted optical Maintenance foreman and mechanics had .
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Although both alignment methods are valid, the inspector was concerned that the mechanics and foreman were not informed of processes which could reduce radiation exposure by reducing i
time in radiation fields. The licensee is reviewing training I and technical information provided to foremen to determine if timely and adequate information is provided to Hechanical Maintenance foreme (2) The work order required all workers to attend the tailboard l
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discussion. However,' the mechanic performing alignment of the pump and motor coupling had not attended the tailboard. 'The licensee stated that coupling alignment activities are highly specialized, and in this case did not require attendance of the
! taliboard, in that the mechanic had been briefed on the job and provided adequate information to perform the work safely. The
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inspector noted that the procedure requirements and expecta-
! tions for specialists regarding tailboard attendance were not specific, and may be subject to incorrect interpretation, par-titularly during times of high work activity such as an outag The licensee was planning to review expectations regarding attendance at tailboards before the next scheduled outag These issues will be followed during routine resident inspection activitie No violations or deviations were identifie . Surveillance (61726)
the inspectors assessed compliance with TS requirem procedure and that test dispositione results met acceptance criteria or were app These tests included:
STP 1-18W2D, Revision 5. Isntopic Calibration of Plant Vent Hid Range lodine Radiation Monitor RM-32
STP R-3A, Use of flux Happing Equipment (Unit 2)
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STP H-11B, Gravity (UnitHeasurement 1) of Station Battery Voltage and Specific
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Established (Unit 2)STP H-45B, Containment Inspection When Cont
STP H-51A, Routine Surveillance of Containment Fan Cooler Unit (CFCU) for Reverse Rotation (CFCU 2-4) STP 1-18W2 Rance lodine RadiationRevision 5. Isotooic Monitor RM-32 Calibration of Plant Vent Hid 1 During review of this surveillance activity, the licensee noted that several In:trumentation and Control (I&C) calibrations had been
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performed during the interval specified TS grace in the TS . period (25% beyond the surveillance The 'Tspector was informed by 1&C technicians that routine use)of the grace perivd was being sto by management, and that surveillance activities have more recently been and will in the future continue to be performed within the TS interva document QE Ho. 9766, dated MayThis effort was documented in p 27, 199 The inspector reviewed a sample of recent 11C surveillances, and found that more recent sur-veillance tests had been accomplished within the TS interval, rather than during the grace period, as was the case for some surveillance activities performed more than six months ago. This licensee
"itiative was noted by the inspector to reflect a more conservative approach to the scheduling of surveillance activitie Procram to Unorade Radiation Monitor Calibr> tion Procedures Tb inspector observed implementation of a review of radiation ecnitor calibration procedures to identify vague or' conflicting guidanc and several action requests.The licensee had identified this effort in an a appeared appropriat The review and associated effort part of routine resident inspection of surveillance activities. Fo i
No violations or deviations were identified, Enaineerina Safety l
Feature Verification (71710(
During the inspection period, selected portions of the safety injection system for Units 1 and 2 were inspected to verify that s tion, equipment condition, valve and e,ectrical lineups,ystem and local configura-breaker positions Specification were in accordance with plant drawings and Technica No violations or deviations were identifie .
Iramoles_of inadeavate Problem Identification Plant Construction Obscures 10 CFR 50. Accendix R. Lichting underway to strengthen masonry walls.in Unit 1, Buses G and was hung from floor to ceiling along the length of one wall to pr tectMay On the19,switchgear 1992, from debris generated by the construction work .
lighting for both rooms was covered byEmergency the tarps.the light-inspector operator actions in the event of a fire.ing is installed in the 4K and EP M-10, Fire Protection of Safe Shutdown E ,
The licensee documented the problem in AR N , and replaced of the lights with transparent plastic.an approximately 6 f t by 5 ft to evaluate operability of the lighting, and assigned systemThe licens m __ _ _=
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-9-engineering responsibility for Appendix R lighting to the fire protection and emergency services organizatio Appendix R,Section III.J requires emergency lighting in all areas needed for operation of safe shutdown equipment. The operability of the lighting, and root cause of the failure to identify and correct the problem until noted by the inspector, will be followed as Unresolved Item 50-275/92-16-0 Contradictory System Valves Toraue Documentation for Residual Heat Removal (RHR)
During 230770, review of the evaluation section of Action Request N which identified recent indication of leakage fram Unit I valve RHR 8702, the inspector noted that a second problem was dis-cussed concerning evaluation of inconsistent torque ~ documentatio Torques of 1500 and 2500 ft-lbs for bonnet fasteners were listed in separate reference documents. .This inconsistency was not identified in a separate Action Request as required, and therefore may not have been re iewed by Quality Assurance. Af ter the inspector identified the issue, the licensee acknowledged that the lack of a separate problem identification document was inappropriate, and initiated a second Action Request (267237) to identify the proble The inspector was concerned that, based on ' inconsistent information, fasteners pl ant . with incorrect torque may have been installed in the Licensee investigation determined that the valve manufac -
turer initially recommended 1500 ft-lbs, but had later offered different valve trim designs. The manufacturer then specified 2500 f t-lbs torque because it bounded all design options for this valve line, and documented this value in lata vendor manuals. Recent vendor correspondence validated this assessmen Installation records from 1973 for original design valves showed torques of 1800 ft-lbs, which the licensee considers an acceptable torque valu Additionally, the licensee stated that these valves are specifically inspected for boric acid leakage at least every outage during sur-veillance test STP R-8C, Containment Walkdown for Evidence of Boric Acid Leakage, to comply with the licensee's response to Generic Letter 88-05 concerning boric acid corrosion of fasteners. Because no leakage has been previously observed, the licensee concluded that l
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this is further assurance that fastener. torque is adequate,
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The licensee stated that this issue had not been identified in past because no work had been performed on the two valves of concern, RHR 8701 and 8702, since original installatio The failure to promptly identify a problem adverse to. quality is considered to be a violation of 10 CFR 50, Appendix B.Section XV '
Because the torque inconsistencies did not appear to be safety significant, and because licensee corrective actions were prompt, this violation is not being cited because the criteria specified in Section V.A. of the Enforcement Policy were satisfie (NCY 92-16-03, Closed)
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. Uncontrolled information in Electrical Panels During routine inspection activities, the inspector observed uncontrolled, outdated, and in some cases inaccurate drawings and circuit panel lists attached to the inside of several electrical breaker The presence of uncontrolled information in electrical panels, particularly in Class 1 panels, was of concern. Afte discussion with the inspector, the licensee determined that this information was inconsistent with the requirements of Administrative Procedure AP C-55, and indicated lack of a formal program for updating electrical labels as part of the design process. Licensee
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work control and operations procedures reautre use of controlled l drawings and information for work associated with these panels.
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uncontrolled drawings did not appear to have encouraged the licensee to circumvent the use of controlled drawing significance of uncontrolled drawings in panels appeared low.Therefore, the Removal of uncontrolled information from inside electrical panels will be followed by. routine inspection activitie One non-cited violation was identified (paragraph 8 b).
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Potential tieakness in Understandina the Recirculation phase Desion Basis In recent months, the inspector has noted the occurrence of five issues
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which appear to have been partially caused by insufficient awareness of design follows:basis requirements for the ECCS recirculation phase. They are as
Diaphragm 92-09). Valve Leakage May Have Exceed Part 100 Limits (LER 5
DC 0-92-tis-fiOO7) . Charging Pump and Safety injection Pump Runo
Leakage Path Vulnerability Via volume Control Tank (VCT) Outlet Check Valve (LER 50-275/92-01).
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Inaccurate Single Failure Analysis Allows the Possibility that Com-Bearing Temperature, Limits may be Exceeded (LERpone
50-275/91-18).
Inaccurate Single Failure Analysis Allows the possibility that Long Term Containment Temperature Profile Assumptions may be Exceeded to Lack of Containment Spray (ifCR DCO-92-Eti-fiOO2),
The inspector identified to the licensee that these issues may indicate insufficient understanding and integration of ECCS recirculation phase design which have requirements, not yet beenwith the potential for additional safety issues identifie evaluate this possibilit The licensee agreed to consider and The licensee identified that'this may be a:
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generic Westinghouse design issue, and was planning to explore this issue with the Westinghouse Owners' Grou evaluation will be tracked as followup ItemFollowup of the licensee's 50-275/92-16-04.
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1 Licensee Event Report followun (92700)
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.' Unit 1 Control Room Ventilation System Outside Desian Basis JLER 50-275/83-39. Revision 0). Closed
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On November 21, 1991, the licensee identified that the control room l ventilation system could be outside its design basis as a result of ,
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! a single failure of a booster fan or its associated damper. The i fans are positioned in parallel flow paths, and failure would allow unfiltered air into the control room during the pressurization mod , ,
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As a temporary corrective measure, the licensee issued Operations i i
Department night orders to the control room discussing- the vulnera-
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bility, and installed flow indicators on ducts in the control roo The licensee also changed emergency operating procedures to require i
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t the ducts by observing the flow indicators. verification that '
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The licensee has prepared and scheduled a design change to provide permanent close resolution of the vulnerability. Therefore, this item is
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Unit 1 Check Revision Valve Inservice Testino Deficiencies (LER,_50-275/84-4 ). Closed
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As a result of deficiencies in the check valve in testing in the closed directio Identification of these valve.;
i occurred August after review of a Westinghouse Infon..ition Letter dated 4, 1989.
The valves, MS-5166 and -5177. are in the steam
j Testing was in place to verify the valves opened
when required, but not that the valves closed in order to prevent an intact steam generator from blowing down through the AFW pump s i supply line to containment after a main steam line break. The NRC i approved a relief r..aest to allow the licensee to disassemble and 3
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inspect the valves on a rotating refueling outage frequency.
i licensee IST progra has added this testing and inspection requirementThe to the This item is therefore closed.
e : Unit 1 Emeroency Diesel Generator (EDG1 1-1 Failure to Start l 150ecial Reoort 50-275/09-01. Revisions 1 and 2. Open item 89-01-X0)
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On 1-1 February 1, 1989, during a routine surveillance procedure, EDG failed to star j Two of the four air start motors failed as a i
result and of shaft rotor overload of the pinion retainers, pinion retainer bolting i The licensee entered TS action statements '
corresponding to an investigation and repai inoperable diesel generator, and commenced
, failure to inadequate fit-up of the pinion gear and rotor shaf during plant maintenance, resulting in improper torque transmitta , The licensee identified several possible contributory causes,
. including excessive Train "A" starting air pressure, improper vendor l
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tolerances for slot fabrication of the pinion retainer, inadequate vendor retainer assembly bolt lockinginstructions mechanism.for the motor, and an inadequate pinion provided inspection results for the remaining 18 air start m which 10 withidentified 11 additional air motors with incorrect fit-up and rotor crack ' The licensee documented corrective action for each of the a the diesel air start configuration. listed causes, and perform air start system was ade The licensee concluded that the actions, was acceptable.quate and, in conjunction with corrective
i The licensee discussed their findings with the vendo indicated that they were not aware of any similar failures.The vendor The licensee informed other licensees of their findings through an
! industry problem communications system.
l subject of NRC Information Notice 89-84. This issue was also the l
The above actions appeared appropriate This item is closed, Unit l_FJel Movement
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_ (LERHandlino Buildina 50-275/89-1 Ver.tilation Revision 1). Closeg Inocerable Durina On Januvy 18, 1991, the Unit I fuel handling building failed to The licensee determined that the fuel handling bu system had been inoperable since October
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15, 1989, when fuel
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movement occurred during the Unit I third refueling outag leakage to be gaps in sheet metal siding, unse penetrations missina or degraded door seals, gaps between the
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movable crane, wall and the fixed walls, through-wall oxidation o sheet metal siding, and reduced flow through the ventilation ducts due to accumulation of debris. Because seali boundary provided adequate negative pressure,ng of the pressure the root cause was considered to have been degradation of the building seal Based on observation the fuel handling of the implementation of the design change building seals and licensee action which has maintained continuing awareness o,f fuel handling building ventilation operability, this item is close Jnocerable Unit 1 Valve Due to limitoroue Sprino Pack Relaxation (LER 50-275/90-09. Revision 0). Closed i
In March,1990, during overhaul of a safety injection system valve a spring preloa expected pack for a motor operator was found to have a less than ,
valves, and was verified to be the result of spring datio pac affected. Nine valves in each unit were identified as potentially Update Bulletin which indicated that valve models o
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i may also have spring pack relaxation.
j After review of maintenance records and valve diagnostic information, the licensee determined
that no additional valves were affected at Diablo Canyon. The
{ licensee replaced each of the potentially affected springpacks, and i evaluated identified as thedegrade safety significance of the spring packs which had been i Based on the as found evaluation, the ;
j licensee concluded their safety functio that the affected valves would have performed
corrective action, this item is closed. Based on this assessment and th k
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j Failure to Perform Hourly Unit 1 Fire Watch -(LER 50-775/91-1 Revision 0). Closed
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j On September 17, 1991, a roving hourly fire watch was not performed
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in some of the safety related equipment rooms. The fire watch was
delayed leaving the radiologically controlled area, and was not able to contact his supervisor in time to prevent violation of the Technical Specification requiren.ent.
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To corrective actions, an incident summary was prepared and training. with fire watch personnel, and included in fire. watch reviewed Written instructions have been provided to personnel for O actions to take if delays occur on round close Therefore this item is
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j Inocerable Unit 1 EDGs While Fuel Pool Crane Was Operatino Over Fu I
Pool (LER 50-275/91-14 Revision 0). Closed _
l On February 13, 1991, with the core offloaded, all three EDGs beca inoperabl '
i spent fuel poo During this time, irradiated fuel was moved in the
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Although a specific operational mode was not in force, the licensee determined that the intent of TS 3.8.5. (Electrical Power Requirements) was not met, since loss of offsite
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j power would have resulted in loss of fuel handling buil."ag venti-
latio The licensee returned EDG 1-2 to service on February 13.
i For corrective action, the licensee issued procedural guidance to i
interpret electrical power requirements to include operational i conditions when the core is offloaded. This corrective action appeared appropriat This item is close h.
i Missed 9]-1 Rod 0).
Revision Position Closed. Indication Surveillance. Unit 1 (LER
j from November 14 to llovember 16, 1991, rod position surveillance
tests were computer missed (PPC) as a result of inadequacies in the plant process softwar i i After the PPC was shut down and restarted a
breakers' status as open.on !!ovember 14, the PPC incorrectl
j the alarm function of the rod position deviation Licensee monitor.Th corrective actions included assessment that rod position had been j
- PPC software, operator training to identify rod p i monitor inoperability, and revision of procedure AP C-27, Comput
- Software Quality Assurance, to ensure significant computer functio
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are verified on an appropriate schedule. These actions appeared appropriate, and this item is closed, Unit I low Vacuum Turbine Trin and Subsecuent Reactor Trio D Procrammatic Deficiency (LER 50-275/92-04 Revision 0). Ope This event is described in paragraph 4.a of this report. The LER will be icf t open for followup of licensee corrective actions ,
related to posting local procedure '
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( Inonerable Unit 2 Fuel Handlino Buildino Ventilation System Durina fuel Movement (LER 50-323/90-02. Revision 2). Closed As a result of inadequate planning and understanding of fuel handling building ventilation system operability requirements, the licensee moved fuel in the spent fuel pool while the fuel handling ventilation used boundary for outage work.doors were blocked open with temporary hoses
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was not adequately maintained.As a result, the required negative pressure The licensee reviewed this event with Operations and Maintenance personnel, and posted signs on all affected during fuelciocrs announcing the need to ensure that doors are closed 4.ovemen therefore, this item is closed.This corrective action appeared adequate; l
t be addressed in Followup ItemCorrective action for the generic this repor /91-27-02, documented later in This item is therefore close k.
l Two Unit 2 Main Steam Safety Valves Set With Inoperable Test fouipment (LER 50-3?3/91-02. Revision 0). Closed On August 26, 1991, main steam safety valve setpoints.the licensee performed routine verificat it became apparent that the test equipment had failedAfter .
two valves we First, FV-60
had been adjusted (PSI) change in setpoin +3 flats, rougP, a 33 pounds per square inch
! roughly corresponding to 143 psi setpointBecause change.Then, of the RV-225 unexpectedly high magnitude of adjustment, the licensee suspected
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l and promptly Yalve RV-225 was confirmed improper declared inoperabl performance of the test equipmen declare valve RV-60 tude of adjustmen inoperable, based on the small, expecte Subsequent testing 4 psi above its +/- 1% tolerance range, found that RY-60 lifted
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l while setting RV-225, and had been operable wh The licensee also concluded that there was no firm evid since setpoint drift is common and expected ,
Because up to +
RV-60 was not declared inoperable after test equ confirmed, the NRC concluded that this was a nonipment failure was (50-323/91-24-02), cited violation based on the low safety significance of the as -
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found setpoint of RV-60, the licensee's prompt corrective action to !
fix the test equipment and validate the actual safety valve set- l l
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points, and continuing for operability improvement in documentation of the rationale decision Therefore, this item is close .
Jnadvertent Removal of Power From Unit 2 RHR Puen_Sumn Suttign Valve Op.tra_ tors Before Enterina Mode 5 (LER 50-323/91-0 Closed Revision 0).
On September 1, 1991, control room operators determined that both RHR sump suction valves and both containment spray (CS) pumps were inoperabl The RHR valve breakers hi.d been opened locally, and control power to the CS pump breakers had been remove Both events occurred after entry into hot shutdown earlier in the day, and were corrected within 15 minutes after identification by operator For the RHR valves, power must be removed from the valves at the control room contactor toggle switches (rather than the local breakers) to satisfy safety analysis requirements that power be able to be restored from the control room. Procedure OP L-5 required power be removed from the valves at the local breaker, thus violating safety evaluation requirement L-5 and reviewed all other L-series procedures.The licensee revised OP For the Containment Spray pumps, power was removed before entry into Mode a Senior5 Control as a result of inadequate control and review of clearances by Operato Specific licensee corrective actions included issuing an Operations incident Summary and memoranda stressing the significance of this event and the need for ensuring TS commitments are me Corrective l
action for the generic concern of personnel errors will be addressed in followup Item 50-275/91-27-02, This item is therefore close documented later in this repor Shift of Unit Revision 2 Control Room Ventilation Mode50-323/91-0 ). Closed (LER On October actuation 3,1991, an inouvertent engineered safety features (EST)
occurred.
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two operators who lifted an incorrect lead while ittempting remove an inverter from service. Power was interrupted to inverter lY-23, to resulting in a the pressurization shift of the control room ventilation system mod expecte All safety systems functioned as The operators followed generic procedure guidance instead of detailed information provided in an attachmen As corrective
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and the procedure was revised to delete the generic emphasize detailed information.
l Corrective action for the generic concern of personnel errors will be addressed in followup Item 50-275/91-27-02, therefore close documented later in this report. This item is
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,0 UnitClosed Revision 0). 2 Safety In_iection While in Mode 5 (LER 50-3?3/91-On October 6, 1991, during a refueling outage (Mode 5), technicians inadvertently caused a safety injection signal by performin prctection switch positioning out of the correct sequence. gThe cause of the event was inattention to detail. All expected ESF actuation signals occurred. No water was injected into the core, since emergency core cooling pumps were secured for maintenanc The technicians were counselled according to the licensee's positive discipline program, and a memorandum was issued by the Plant Manager emphasizing the need for procedure ccmpliance and verificatio Lorrective action for the generic concern of personnel errors will be addressed in Followup Item 50-275/91-27-02, documented later in this report. This item is therefore closed, linit 2 RER Valve leakace 50-3?3/91-0 Hav Have Resulted Revisions 0 and 1). Closed in Exceedino 10 CFR 100 Do 09 October 4, 1991, 1.3 gallons per minate leakage from diaphragm vsives CVCS-2-8471 and -548 was evaluated by the license The evaluation concluded that the control room and exclusion area boundary 10 CFR 100 limits could have been exceeded during the recirculation phase of a loss of coolant accident (LOCA).
The licensee determined that the diaphram service life for CVCS-2-8471 had been exceeded and that diaphram degradation had resulted in leakage. The LOCA analysis had not identific CVCS-2-8471 as a i valve in the recirculation phase flow path, as a result, the valve was not included for diaphragm in the licensee's preventive maintenance program replacemen had not been retorqued at normal operating pressure a following maintenance, as was required for that type valve.perature
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The licensee ccamitted to revise the procedure to include this ste While this specific issue is closed, the inspector was concerned that other issues concerning the design requirements of the recirculation phase may not have been adequately-addressed, and documented the n' ecd for NRC followup of this concern earlier in this repor ' Jnprerable Unit 1 Vide Rance Containnient Sumo level Indication JLfR 50-3?3/91-10. Revisions 0 and 1). Closed On October 22, 1991, with Unit 2 in Mode 2 at Ot power, TS Action Statement 3.3.3.6 was exceeded due to the reactor cavity sump wide
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channel was returned to service about 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> Thelater. range
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failure to met the TS action statement was caused by inadequate corrective action for a previous similar occurrenc During investigation of a similar failure on March 15, 1992, the licensee determined that only the zero range was affected by the failure, and all the ranges required for the indicator to fulfill its safety function were operable. The licensee considers previous failures to be similarly of low safety significanc ,
In Inspection Report 50-323/92-01, the NRC issued a violation concerning the inoperable sump level indication. This item is close FailureRevision 91-1). to Test a 0).Unit ? ECCS Valve After Maintenance (LER 50-323/
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On October 17, 1991, while in Mode 5, the packing on ECCS valve SI 2-8802B was adjusted and the packing gland follower nuts were torqued to a value greater than the torque used for the last successful stroke time test. Both these operations result in requiremc..ts valve to perform to operable status.a post-maintenance test before returning the However, neither requirement was immediately recognized. During mode change review on October 22, the deficiency was recognized, and the test was performe As corrective action, training on mode transition was provided for the Engineering Test Group, an Operations event. report was issued, and work planning issued enhanced work policies. Corrective action for the generic concern of personnel errors will be addressed by Followup Item 50-275/91-27-02, This item is therefore closed, documented later in~this repor . Doen item followup (927031 Public Address (PA) System Powered by Non-Vital Circuitry (Followuo Jtem 50-275/91-09-03). Closed During the loss of offsite power event on March 7,1991, operators were unable to quickly inform workers in the' containment of plant status because the PA system was powered from non-vital powe Containment syste was evacuated in an orderly manner without use of the PA sources during The licensee outages.plans to implement control of PA system power item is close Based on planned licensee actions, this EDG Slow to load (Followuo item 50-275/91-09-04). Closed This item discussed the failure of EDG 1-1 to load onto the vital bus within 10 seconds during the loss of offsite power event on March 7, 199 After NRC review of the circumstances, the licensee received a violttion associated with determinstion of the validity i of the start failure (50-275/91-07-10). No other issues were identified. Therefore, this item is close )
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Refuelina Procedures Chanon_(Followuo item 50-275/91-09-05). Closed
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Juring the loss of offsite power on March 7,1991, a concern was a loss of offsite power. identified regarding the safety of fuel asse The licensee identified a comitment based on INP0 SOER 85-01 to change procedures to include actions to place
, fuel assemblics in a safe location durin cooling concurrent with a loss of power.g loss of refueling cavit The inspector reviewed Revision 11 of procedure OP S-8DS2, Core Loading Sequence, which was revised to include a step which does not allow a fuel assembly to be li'ted from the spent fuel pool until the previous assembly has beer unlatched in the cor The inspector verified that a similar requirement existed in the core action,unloading this itemprocedur is closed.Based on the licensee's corrective Inonerable Wide Rance Reactor Cavity Sumn (Followup 01-03). Closed Item _50-323/92-The NRC reactor issued cavity sumpalevelNotice of Violation due to inoperable wide range indicatio has successfully identified and corrected failure of the sump leve indication on two occasions, as a result of more attention to Technical Specification operability requirements. As permanent corrective action, continued troubleshooting and repair work on the level indication has occurred during unscheduled outage ,
change outag has been reviewed for installatien during the next scheduledA
- planned corrective action, this item is closed. Based on th Increase in Personnel Errors (Followun item 50-275/91-27-021. Ooen
number of personnel errors, foiiow of corrective iten will include the generic corrective actions for licen reports documented above which were caused by human error.see Indica- event tion LERs of successful by humanactions error. Thiswill iteminclude reduction of the n i
caused remi. ins ope Spurious Actuation of Carbon Dioxide Fire Suporession System in J-3 Room (Unresolved Item 50-275/92-05-01). Closed ,
dioxide (cardox) suppression system actuated.During The ventilation for generator coolitig closing the west wasdoor rolldown then cut off as a result of the cardox system l prevent overheatin Operators shut down the diesel to failure of the diesel. The NRC questioned whether this was a valid Because the root cause is still under failure evaluations in response to an ,NRC issue is close this notic Followup of the issue of validit
! be part of routine resident inspector activities. y of failure will l
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.. Comnariton of ticuid Radwaste Analysis Results (followuo item 10-275/88-33-01). Closed This item concerned an inter-comparison of iron-55 (Fe-55) activity in a liquid radwaste sample that was split between the licensee and the NRC contract laboratory. The initial inter-comparison of analytical results for Fe-55 did not agree, and a followup inspection was conducted at the licensee's off-site laboratory. The inspector found that the licensee's laboratory sampling and measure-ment techniques were fundamentally sound. To resolve the issue, the inspector, in coordination with the licensee, devised an experiment to independently verify both NRC's and the licensee's analytical methods for determining Fe-55 in liquid radwaste. A liquid radwaste sample, spiked with FE-55, was split between the HRC contract laboratory and the licensee. The amount of FE-55 activity was known only by the inspecto Based on the results of the inter-comparisons, the inspector concluded that the licensee's method for analyzing liquid radwaste for FE-55 is satisfactory. This item is close . Followup on Unresolved items (927011 Auxiliary Salt Water (ASW) Floodino Due to Failure to Follow Proce-dures (Unresolved Item 50-275/91-24-01). Closed On August 2,1991, flooding of the component cooling water heat exchanger area occurred as a result of maintenance workers' failure to follow clearance instructions in the order specified. Review of the safety significance of this issue determined that the other trains safety their of CCWfunction and ASW were available and would have performed Licensee corrective actions included issuing a maintenance event sumary, counseling the individuals involved using positive counseling, properly and emnhasizing following clearances.the personal and plant safety aspects of The failure to follow clearance instructions appears to be a viola-tion of Technical Specification 6.8.1,~ which requires that work be implemented by procedures. Based on the licensee's corrective action and the low safety significance of the concern,-the violation is not being cited because the criteria specified in Section V.A. of the Enforcement Policy were satisfied (92-16-05, closed), Senaration of Safety Related Electrical Circuits (Unresolved item 50-275/91-11-01). Closed i The licensee had previously identified that two independent Class IE l direct current (dt) supplies were electrically connected in a non-
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Class IE fire horn relay pane within the pane There was no electrical separation
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The licensee concluded that connection of the two Class IE de supplies in the relay panel was within the separation criteria established by their licens An inspector also previously noted that both Class IE cables and non-Class tio IE cables were being routed through a new Conax penetra-The licensee stated that they were using Regulatory Guide (RG) 1.75, " Physical Independence of Electrical Systems," when feasible during design modification were using coax cables, for which there were no spare penetration Therefore, the licensee concluded that separation per RG 1.75 was not feasibl The inspector determined that the routing of both Class IE cables and non-Class IE cables through the new Conax penetration would be further reviewed for acceptable electrical separation. The review would be performed in conjunction with the review of the accepta-bility of electrical separation within the fire hora relay pane The inspector evaluated both of the previously identified items discussed abov predated RG 1.75. The inspector noted that the Diablo Canyon design 308-1971, " Criteria for Class IE Electrical Systems for Nucle Power Stations." Paragraph 5.3.5 of IEEE 308-1971 stated that protective automaticall devices shall be provided to isolate failed equipment The inspector reviewed the circuit design and concluded that the Diablo Canyon design for protective devices was Class IE de supplies. adequate to prevent faults in non-lE Class pane The inspector al.o concluded that the installation of bth Class IE criteria 'or Diablo Canyon.and r.on-Class IE cables in a new Cona The inspector concluded that lack of a ,
i spare penetration was a reasonable evaluation for concluding that installing the new cables per RG 1.75 criteria was not feasibl This item is close Kilovolt and Switchaear 50-323/91-07-01). Closed Fault Current Ratino (Unresolved Item The Electrical Distribution System functional Inspection identified ratings during certain plant operations.that calculated fault cu exceeded switchgear ratings when one or more emergency dieselCalc generators (EDGs) were operated in parallel with the main generato The licensee took action to minimize the tests which required para-llel operation of the main generator and one or more EDG The licensee also took action to minimize the fault capability of the main generator during parallel operation with an ED .
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The licensee perfonned a calculation which showed that a maximum (bolted) fault was a low probability event during the limited time the main generator was operated in parallel with an ED ;
l The NRC staff calculated the core damage frequency caused by the {
occurrence of a bolted fault during a time when the main generator was operated in parallel with an ED The calculation showed that the core damage frequency caused by this bolted fault was in the order of 1.0E-9 per reactor year or_ les The inspector reviewed the licensee's actions and concluded that these actions adequat to minimize the risk from a bolted fault were The inspector reviewed the licensee's calculation and concluded that this calculation was adequate to demonstrate that a '
bolted fault during parallel operation of the main generator and an EDG was a low probability event. The inspector also concluded that the core damage frequency calculation demonstrated that the bolted fault condition discussed above had little safety significanc This item is close .
Verification of As-Built Drawinas (37051 and 500731 On April 24-25, 1992, the inspector entered containment to examine containment fan cooler damper 2-4 to verify the licensee had restored The inspector used the following documents as the basis inspectio .
American Revision 6, Warming & Ventilating, record 663079, Sheet 37 Inc., Drawings SHW-D-9098, PG&E 81010-001-000 Revision A, PG&E recor;dSHW-D-9099, Revision B; and 663079, Sheet 75
Design Springs Change Notice DC2-EH-44664, CFCU Backdraft Damper Helpe
Non-Conformance Report DCO-92-MM-N007, Containment Fan Coolers The inspector observed that the backdraft damper appeared to conform to the design documents with two exception First, several of the Allen )
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I vane linkage arms appeared loose in the holes in the did not close contact The gap was 1 the rubber block shock absorbers whe specify any clearances /16 inch or les related to these observations.The design documents did not
When questioned by the inspector, the Mechanical Hair.tenance Engineer showed the inspector an Action Request which had been written regard the loose fit of the shoulder bolts in the linkage arm The licensee concluded that this deficiency would not have preventeo the damper from working and refueling outag planned to completely overhaul these dampers during the next
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The inspector re-entered containment to observe the surveillance testing (M-51A) of damper 2-4 to determine if the lack of contact with the shock absorber block would affect the operability of the dampe observed that : tarting and stopping the associated containment fan coolerThe insp unit caused the damper to swing open and shut over a period of several second would not be significantly affected by the counterweights the shock absorber bloc The inspector requested that the licensee evaluate the the dampers. effect of the observed gap on the post-LOCA performance of The licensee evaluated the observation and concluded that during a LOCA with the gaps measured by the licensee, the flexibility of the linkage ,
mechanism and the dampers was sufficient so that the shock absorbers would atsorb any significant shock to the linkage arm No violations or deviations were identifie .
Infomation Meetino with local Officials (94600) i On May 4 i County Administrator, Deputy Administrator, and Emergenl Coordinato The purpose of the meeting.was to introduce the NRC inspectors, to offer the NRC's openness to discuss inspection report findings with the County, and to discuss general issues of emergency plannin !
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1 Exit Meetina i
An exit meeting sentatives was identified conducted1.on June 12, 1992, with the licensee repre-in Paragraph I
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The inspectors summarized the scope and findings of the inspection as described in this repor !
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