IR 05000255/1990010
| ML18057A267 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/06/1990 |
| From: | Yin I NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML18057A266 | List: |
| References | |
| 50-255-90-10, CAL-RIII-86-02, CAL-RIII-86-2, NUDOCS 9006180327 | |
| Download: ML18057A267 (13) | |
Text
U.S. NUCLEAR REGULATORY COMMISSION REGION I II Report N /90010(DRS)
Docket N License No. DPR-20 Licensee:
Consumers Power Company 1945 West Parnall Road Jackson, MI 49201 Facility Name:
Palisades Nuclear Generating Plant Inspection At:
Palisades site, Covert, MI 49043
,?-5 Butler Approved By:~
Monte P. Phillips, Chief Operational Programs Section Inspection Summary 64/ro Date 6/e619o Da e C/6/?g Date Ins ection on March 13-15, A ril 2-6, and May 9, 1990 (Re ort No. 50-255/90010(DRS))
Areas lnspecte :
outine, announce inspection o icensee on iguration Contro Program (CCP) implementation responding to the NRC Region III Confirmatory Action Letter (CAL-RIII-86-002), dated May 21, 198 The licensee CCP efforts for Component Coo 1 i ng Water, C 1 ass 1 battery, 125 VDC power supply, and 4 kv AC power supply systems were reviewed during this inspectio The inspection was based on selected portions of NRC Inspection Procedure 9272 Results:
Licensee effort in developing and implementing the CCP was enormou The licensee 1 s CCP results were mixe Specifically:
0 The Component Cooling Water (CCW) Design Basis Document (DBD) review did not compile sufficient information regarding the major system design bases, resulting in the lack of a sufficient baseline for the performance of the Safety System Design Confirmation (SSDC).
This resulted in the licensee 1 s recent decision to re-perform the CCW evaluatio The CCP completion schedule has slipped from 1989 to the present estimated date of 1993 based on the need to complete the DBD effort prior to implementing the associated SSD ~DR ADOCK 05000255 W
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- There were many discrepancies identified by the DBD and SSDC efforts where the significance of the finding had not been determine The licensee was providing additional resources to perform these determination The CCP scope did not incorporate walkdowns of mechanical systems, although these were performed for the SSDC on electrical system The licensee was not performing these walkdowns as a matter of routine because it felt that walkdowns performed prior to the initiation of the CCP would have identified all concern There were several recent examples where the licensee had identified discrepancies between the fuse size specified on the drawings and those installed in the plant that resulted in drawing changes without an engineering evaluation to determine whether the original drawing or current installation was acceptabl The DBDs and SSDCs performed for the 4160 VAC, station battery, and DC power systems appeared to be very goo The licensee had identified and documented many significant safety issue The licensee's corrective actions and schedules appeared to be reasonable, with the above noted exception, once the finding's significance had been determine The licensee utilized a substantial amount of resources in the performance of field walkdown verification of wiring diagrams and upgrading of the*
Q-listings and backup vendor documentatio The discrepancies (except fuse deficiency control) identified had been corrected in a timely manner.
The review of the findings associated with the CCW system indicated that the licensee had not definitively determined the cause of recent wall thinning that had occurred in some CCW heat exchanger tube The licensee has committed to expand the eddy current testing planned for the Fall 1990 outage to address this concer I
' DETAILS Persons Contacted Consumers Power Company (CP)
+*D. J. VandeWalle, Safety and Licensing Director
- J. R. Brunet, Licensing Analyst
- K. E. Osborne, System Engineering Superintendent
- R. Brzezinski, ICE and M Superintendent
- M. Ferens, Projects Department
+*D. C. Takach, CCP Task Engineer
+*M. D. King, System Engineer
- M. T. Nordin, System Engineer
- J. Schepers, Quality Assurance
+ B. Harshe, Staff Engineer
+ R. A. Vincent, Plant Safety and Engineering Administrator
+ T. E. Leva, System Engineer - Fuse Program Millican and Associates
- L. Hancock, Self Assessment Team
+*J. A. Blewett, CCP Project Engineer U.S. Nuclear Regulatory Commission
+*E. R. Swanson, Senior Resident Inspector
+ M. P. Phillips, Chief, Operational Programs Section
- Indicates those attending the exit meeting at the site on April 6, 199 + Indicates those attending the followup meeting at the site on May 9, 199 Other licensee personnel were contacted as a matter of routine during the inspectio.
Introduction On May 9, 1986, the Palisades plant tripped from 97%
power due to loss of the main turbine electrohydraulic syste During plant shutdown, several components failed to operate as expecte This ultimately resulted in NRC issuing a Confirmatory Action Letter (CAL-RIII-86-002), dated May 21, 198 The CAL, in part, specified that the licensee perform "a thorough investigation of plant safety systems and balance of plant system important to safety, with regard to operability and required maintenance."
Consumers Power (CP) letter to NRC Region III, dated December 1, 1986, committed to the implementation of a Configuration Management Project, which included (1) design basis documentation, (2) plant configuration and configuration Documentation (PC&CD), and (3) configuration contro The project was scheduled for completion in 198 *
The Configuration Management Project was renamed the Configuration Control Project (CCP), and was modified to include:
(1) design basis documentation (DBD); (2) field verification; and (3) safety system design confirmation (SSDC) project One of the major differences between the initial program and the current program was that the earlier PC&CD had been designed to assure 11what exists physically in the plant satisfies the design basis, and that design documentation accurately reflects the physical plant 11 (CP December 1, 1986 letter to RIII), while the present field verification activities covered only wiring panel verifications and Q-list data base update and validation, and did not include mechanical system field verification (see paragraph 4.a).
After the development of the DBDs, the licensee initiated the SSDC revie This review included the following areas:
(1) design review; (2) design basis document review; (3) maintenance review; (4) document control review; (5) operations review; and (6) testing revie The DBD for the CCW system was completed in May 198 During the DBD process, the SSDC was initiated for this syste At that time, many of the issues identified during the DBD were not sufficiently characterized to determine importance and therefore a corrective action implementation schedule was not availabl As a result, the SSDC was unable to confirm the DB In addition, four audits were conducted on this DBD, two by the NRC, one by the licensee's QA department, and one by a licensee consultan As a result of the findings from these audits, a writers guide was developed for the preparation of future DBD After completion of the HPCI DBD utilizing the writers guide, the licensee decided to redo the CCW DBD with completion scheduled for December 199 Based on this experience, the licensee had decided to hold off on the initiation of SSDCs until the associated DBD effort was complete With this in mind, the licensee projected that the completion date for the configuration control project (CCP) would be extende CP letter to NRC Region III dated January 23, 1990, revised the project completion schedule to the second quarter of 199 The schedule may slip based on the decision to complete the DBD portion of the project prior to initiating the associated SSD The purpose of this inspection was to assess the adequacy of the CCP and the effectiveness of corrective actions responding to CCP finding.
CCP Completion Status and Open Items During the performance of the CCP efforts, the licensee identified discrepancies, which were categorized into three area Discrepancies in the first category were considered to be minor, and should be capable of being corrected as part of the CC These discrepancies were associated with drawing errors, or other minor condition The second category related to issues that had not yet been characterized as to their 4*
- significance. These issues involved areas where additional information was needed to determine if the discrepancy was minor, or majo Additional action was required by the licensee to evaluate these issues for transfer either to category I or category III. The third category was major discrepancies, and in most cases involved a change to the facility. These category findings were placed into the licensee's normal corrective action system with the issuance of a deviation repor As of the date of this inspection, the licensee completed the following system evaluations: Mechanical/Nuclear DBDs ccw Approximate Start Date 3/1/88 Report Issuance Date 5/4/89 The DBD documented 62 minor discrepancies, 4 major discrepancies, and 22 discrepancies where the significance had not yet been determine Electrical - Emergency Power DBDs Diesel Generator Performance Station Batteries 125 voe (safety related)
Approximate Start Date 1/1/89 9/1/88 6/15/89 Report Issuance Date 6/13/89 9/18/89 1/26/90 These DBDs documented a total number of 14 minor discrepancies, 6 major discrepancies, and 28 discrepancies where the significance had not yet been determine Electrical - Station Power DBDs 4160 VAC External Power Transformers Instrument AC CRD Power 2400 VAC 480 VAC Approximate Start Date 4/1/88 2/1/88 2/7 /88 8/1/88 4/1/88 4/8/88 Report Issuance Date 11/18/88 12/14/88 12/19/88 12/19/88 12/20/88 12/20/88 The DBDs documented a total number of 36 minor discrepancies, 3 major discrepancies, and 21 discrepancies where the significance had not yet been determine r 5.
- Safety System Design Confirmations (SSDCs)
Start Issue Cat III Cat I Cat II System Date Date Items Items Items ccw 4/5/89 6/28/89
5
4160 VAC 8/1/89 10/17/89
2
Station batteries 1/15/90 3/23/90
8
& DC Power In view of the time spent on each DBD and SSDC, the inspectors were surprised to see so many issues where the safety significance had not been determine The licensee stated that they had also recognized this concern and had planned to dedicate additional resources to make these determination The licensee had established a goal to maintain 35% of all Category II discrepancies reclassified, and maintain 35% of all discrepancies close.
Mechanical System Review The inspectors reviewed the scope of the CCP for the component cooling water (CCW) and the licensee's actions regarding two of the discrepancie a.
Component Cooling Water DBD/SSDC Scope The inspectors reviewed the scope of the DBD/SSDC efforts associated with the CC The scope did not incorporate walkdowns of mechanical systems, although these were performed for the SSDC on electrical system The SSDC did include a limited system familiarization walkdown against the P&I The drawing verification program for mechanical systems consisted of evaluate and document the type and extent of any system modifications which have been installed since the Bechtel 12447-033 project (NRC Bulletin 79-14 Pipe Support Verification)."
The licensee was not performing these walkdowns as a matter of routine because it felt that previous walkdowns performed for other reasons would have identified all concern In addition, the licensee's equipment database verification efforts had included walkdowns of 20% of the CCP system equipment for model number and equipment location. These verification efforts did not identify discrepancies between the drawings and field conditions. Therefore, based on the lack of findings from the prior walkdown efforts, the licensee planned to perform walkdowns only to resolve conflicts that could not be resolved based on a documentation search, or if major modifications to the system had been mad However, without walkdowns, it was unclear to the inspectors whether the DBDs could truly fulfill the licensee's objective of establishing a full set of design bases representing the as-installed and as-operated plant configuration.
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Although the scope of the DBD effort was very limited regarding interfacing and supporting systems, this was not the case for the SSDC effort. The DBDs were developed utilizing rigid rules defining the scope of the syste However, the SSDC crossed system boundaries and included supporting/supported systems to evaluate the functionality of the system being reviewe CCW Pump Net Positive Suction Head (NPSH) Discrepancy This discrepancy involved the performance of the CCW pumps after the maximum design temperature had been raised from 140F in 198 At the beginning of the inspection, the licensee had not evaluated this findin During the inspection the licensee determined that this discrepancy did not pose an operability concern because the actual location of the CCW surge tank was more than twenty feet above the design location, which provided ample margin for the related loss of NPSH due to the increased design temperature. In addition, the licensee was actually utilizing a maximum design CCW temperature of 156F rather than 200F, thus providing additional margi The inspectors were concerned that this issue had not been resolved prior to NRC raising the issue during the inspectio CCW Heat Exchanger Performance Discrepancy This discrepancy related to the performance and potential degradation of the CCW heat exchangers (CCWHXs) when operated at flow rates exceeding their desig In 1970, the licensee discovered that the installed CCWHXs were rated at 2850 gpm each versus the 5700 gpm each specified per the desig Initial and pre-operational testing was performed at flow rates exceeding 8000 gpm total flow through the CCWHXs, and with flow shock caused by rapid opening of the heat exchanger inlet valves. This resulted in high tubing vibration and some tube damage near the nozzle region As a result, the licensee plugged several tubes that had faile The CCW flow was reduced to 5700 gpm per heat exchanger in 1971, and 4500 gpm per heat exchanger in 1986, to reduce tube vibration. This revised system operating condition was evaluated and accepted by the NRC in a Safety Evaluation Report (SER) issued on March 20, 198 However, even with these flow limitations, several tubes required plugging in 1975, four tubes required plugging in 1986, and two tubes required plugging in 198 The licensee performed eddy current testing only on tubes in the immediate vicinity of those tubes that were failing. These tubes were in the immediate vicinity of the nozzle region In 1986, the wall losses for the plugged tubes ranged from 40% to 76%.
The wall thinning rates for the two tubes plugged in 1988 were quite fas From January 1987 until September 1988, one tube's wall loss increased from 25% to 97%,
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while the other tube's wall loss increased from 38% to 43%.
The licensee had determined that the 1970's tube failures had been due to flow shock or circumferential tube wear dentin In the later case, this was probably due to the manufacturing proces For the recent tube degradations, the licensee postulated that they were caused by flow induced vibratio However, the inspectors postulated that the cause of the tube degradations may include internal wall thinning caused by erosion and corrosion induced through service water flo The inspectors included this possibility based on the limited eddy current testing performed, the lack of a clear picture of the failure mechanism, and the rapid wall thinning rates found in some tube The tubes that were plugged have been stabilized by inserting a rod in the tubes that makes the tubes rigid and prevents surrounding tubes from becoming excited by motion in the damaged tube An analysis performed by YUBA, a heat exchanger manufacturer, concluded that the vortex shedding ratio at 4500 gpm would be near a normal design value, providing additional confidence that 4500 gpm would be acceptabl However, tube damage has continue The licensee has now raised the flow limitation to 4700 gpm to support the additional decay heat load from the spent fuel poo Although not posing an immediate operability issue, the inspectors were concerned that since the specific cause of the tube degradation had not been determined, the recent increase in the flow limitation may accelerate this degradation.
The licensee had decided to revise its planned CCWHX tube eddy current inspection scheduled for the Fall 1990 outage to cover all the tube region Rings of tubes representing different heat exchanger regions, including the center area, would be sample The test results and data evaluations would be used to form a basis for determining if further corrective actions are necessar Electrical Systems Review The inspectors reviewed the OBOs and SSOCs for adequacy of review scope and implementatio The inspectors also evaluated the corrective actions implemented for some of the discrepancy items to ensure that the actions were effective and completed in a timely manne Volt AC System The 4160 VAC distribution system is a non Class lE, three phase system consisting of four switchgear units, Bus Nos. lA, lB, lF, and l The OBO provided sufficient information and referenced the appropriate information to determine that the design bases were either in place or being evaluated for a*
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reconstitutio The DBD contained an appendix that identified missing design basis informatio Missing information was assigned a CCP control number for future reconstitution effort The SSDC process produced a total of 14 CCP discrepancies, of which five became action item requests and two became deviation report The corrective actions and time frame to implement them were considered to be reasonabl The inspectors reviewed the safety evaluations performed for three associated facility changes (FCs 790, 799, and 800) that had been implemented after completion of the DBD In one case, the effect of the modification was to reduce the time the turbine-generator remained connected to the primary coolant pump busses from approximately 80 seconds to 10 second In the other two cases, extra power transformers and additional bus transfer logic were added to provide additional power sources and prevent overloading the startup transformers 1-1 and 1-3. Although the safety evaluations adequately addressed the design changes, several of the observations from the licensee's SSDC indicated that the DBD had not been updated to reflect these FC The inspectors considered this to be a weakness in the licensee's design control proces To address this weakness the licensee provided a copy of the procedure 11 Facility Change, 11 revision 8, dated January 12, 199 This new FC procedure required the responsible engineer, during the conceptual engineering stage, to identify all applicable design inputs on the Design Input Checklist, and to identify all specific design outputs that need to be developed as a result of the proposed facility change In addition, a new Administrative Procedure patterned after the FSAR control/maintenance program was to be issued by September 199 Although the FC new procedure appeared to be adequate, effective implementation was yet to be determine The inspectors noted that FCs that are past the conceptual engineering review stage may not have properly incorporated the elements of the DBD update progra Station Battery and DC Power The DBD included the engineered safeguard batteries (DOl and D02),
station batteries (D204, 0213, and D214), and the 125V DC distribution syste The 125V DC system consists of two redundant, independent and isolated system Each system is equipped with two battery chargers, distribution panels, switchgear, instrumentation and fuse panels. The DC system is an integral part of the engineered safeguards system.
The DBD for station batteries provided sufficient information and referenced the appropriate information to support the design base The DBD for the DC systems indicated that 12 design items were missing and that discrepancy reports were issued to retrieve or to reconstitute these item The findings made during the DBD process were very goo Deviation reports were issued prior to performing the SSD The SSDC process produced a total of 31 discrepancies, of which 12 became action item requests and eight became deviation report The inspectors considered the proposed corrective actions and time frames for implementation to be reasonabl One of the more significant findings involved the physical separation of redundant power cables associated with the DC chargers and inverters, and was identified as part of the DBD effort. This finding was documented in Deviation Report No. D-PAL-90-040, 11 Inadequate Cable Separation In Cable Spreading Room.
The protection systems were separated into two channels, right and left, with systems 1 and 3 constituting the left channel, and systems 2 and 4 constituting the right channe The Palisades FSAR (Section 8.5.3.2) stated, in part, that all circuits designated as belonging to a safety-related power distribution, Reactor Protection System, engineered safeguards or other safety-related system channel were to be run in separate raceway system In addition, 11 Physical separation (distance) has been considered as the most reliable method of providing the circuit separation and isolation.
The licensee discovered that the DC cables for Inverters Nos. 1 and 3 and Battery Chargers Nos. 1 and 3 were routed in the same cable tray as cables from Inverters Nos. 2 and 4 and Battery Chargers Nos. 2 and 4 without proper physical separation. The AC feeder cables for Battery Charger No. 3 were found bundled with Battery Charger No. 2 cables within MCC No. Battery Charger No. 4 cables were found bundled with Battery Charger No. 1 cables within MCC No. All these cables are located in the cable spreadin~ room. This configuration would allow a fire to result in the common mode failure of this syste The inspectors noted that fire detection and suppression equipment were provided in the room, and that the license had increased the fire watch tour of this area to every half hou In addition, the inspectors reviewed the related operations procedures and considered them to be adequate for the operators to mitigate a loss of DC power for the short ter Based on these reviews, the inspectors concluded that the licensee had taken adequate compensatory measures to address operability. The licensee stated that a voluntary Licensee Event Report (LER) would be issued to document and evaluate the above potential significant discrepancies, but they did not feel that they had violated single
failure criteria. The licensee had performed a safety evaluation and an operability determination for this discrepancy, and had concluded that the system was operabl The licensee agreed to provide the inspectors with documentation regarding the AC coordination for the battery chargers to their appropriate MCCs, and regarding the DC coordination for the battery chargers and inverters to their appropriate DC buse This would be utilized in the LER fo llowu The CCP was preparing to address the potential for other cable separation problems at Palisades as part of task item 2.2 The draft project plan, 11 Enhancement of the Circuit and Raceway Schedule Database," was proposing to restore the completeness and accuracy of the databas The plan was to be implemented in three phase Phase 1 would resolve any remaining issues concerning channel separatio Phase 2 would develop preliminary cable/raceway database separation data and medium voltage cable separation informatio Finally, Phase 3 would complete the database information and perform a sample verification of the databas Completion of the three phases had been tentatively set for 199.
Wiring Diagram Verification and Q-Listing Upgrade Two of the major programs within the CCP, i.e., wiring diagram verification and equipment Q-Listing upgrade, were reviewed by the inspector The inspectors considered the wiring and cable schedule walkdown verification (Task 2.1) for control panels, breakers, and junction boxes for the 13 designated systems to be substantia From the fourth quarter of 1987 until the end of calendar year 1989, more than 37,000 man-hours were spent on the project. Twenty-one DRs had been written to dat The inspectors verified that all of the 18 DRs issued in 1988 and 1989 had been corrected and close In addition, 323 physical discrepancies had been reported covering such items as broken cables, undersized fuses, uncertainty of power sources, and damaged flexible conduit DRs were written for major problems; and work orders were issued for minor discrepancie The licensee performed Q-List component verification and updating of vendor data as part of Task 2.6 for the 13 designated system From the second quarter of 1988 until the end of calendar year 1989, approximately 15,000 man-hours had been spent on the projec To date, three major discrepancies had been identified, resulting in issuance of three DR The inspectors verified that the corrective actions had been implemented and that these DRs were appropriately close To assess the licensee's corrective actions, the inspectors evaluated a selected number of DRs representing fuse control discrepancies, wiring discrepancies, and Q-listing discrepancie With the exception of fuse controls, the licensee's corrective actions for the wiring walkdown and Q-listing discrepancies were considered to be adequat The inspectors reviewed three DRs where the installed fuse did not correspond with the drawing The inspectors determined that the engineering analyses to determine the effect of the different fuse sizes on the circuit were inadequate. These analyses had been performed as part of the corrective actions for these DR In particular, D-PAL-90-051, which was evaluated by the I&C Department rather than the Electrical Department, discovered a 15A fuse installed in a branch circuit to several area radiation monitor The drawing referenced a lOA fus The branch feeder breaker was a 20A, General Electric, Type TQB molded case breake The DR stated that since the 15A fuse was less than the 20A breaker, the configuration was acceptable and the drawing was changed to reflect the as-found fuse size of 15 The DR resolution provided no engineering analyses to demonstrate that the 15A fuse would coordinate with the 20A breake At the inspectors' request, the licensee produced the coordination curves that plotted both a lOA and 15A Bussman fuse and the 20A breake The 15A fuse would coordinate in the breaker thermal region; however, the 15A fuse and breaker did not coordinate for fault currents of 200A to approximately 360A near the bottom of the breaker instantaneous trip regio The lOA fuse also mis-coordinated, although to a lesser degree, for fault currents of 200A to approximately 240A in this same regio Even though it may be difficult to coordinate fuses to molded case breakers, the DR resolution did not provide an engineering analysis to determine if the lOA fuse was the preferred fuse size for this applicatio The licensee had established a fuse policy via Administrative Procedure (AP) No. 4.02, Revision 6, dated September 20, 1989, "Control of Equipment Status."
The licensee had also issued a fuse replacement policy directive on April 7, 1989, which required like for like replacement of fuse In cases where like for like replacement could not be implemented, the policy required that replacement be documented via the Specification Change or Temporary Modification proces The inspectors reviewed Revision 6 of AP No. 4.02 and concluded that the procedure failed to address the replacement fuse model and type being like-for-like, which could affect the time-current characteristics of the fuse even though the amperage capacity may be the sam The licensee agreed with the inspectors' concerns regarding fuse controls, and had drafted a proposed program, "Palisades Plant - Fuse Control," dated May 2, 1990, that was designed to ensure that all fuses installed were acceptabl The proposed program consisted of six parts: (1) uniquely identify each pair of fuses with its own equipment identification number; (2) add all fuses to the equipment database and add fuse identification to the applicable schematics and wiring diagrams; (3) label all fuse holders with the fuse identifier; (4) standardize fuse types in use to as few as possible; (5) use existing current ratings without establishing bases for sizing; and (6) revise Electrical & Maintenance Policy Memo to more closely control fuses until completion of the fuse identification/labeling proces ___ _,I Ex it Meeting The inspectors met with licensee representatives (denoted in Paragraph 1)
on April 6, 1990, at the Palisades Nuclear Generating Plant and summarized the purpose, scope, and findings of the inspectio The inspectors discussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspectors during the inspectio The licensee did not identify any such documents or processes as proprietar