IR 05000498/1993019
| ML20056C980 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 07/23/1993 |
| From: | Powers D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | |
| Shared Package | |
| ML20056C979 | List: |
| References | |
| 50-498-93-19, 50-499-93-19, NUDOCS 9307300177 | |
| Download: ML20056C980 (18) | |
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j APPENDIX ,
U.S. NUCLEAR REGULATORY COMMISSION
REGION IV
l l Inspection Report: 50-498/93-19; 50-499/93-19 !
Operating Licenses: NPF-76; NPF-80 Licensee: Houston Lighting & Power Company i P.O. Box 1700 Houston, Texas 77251 ;
l Facility Name: South Texas Project (STP) Electric Generating Station, Units 1 l and 2 Inspection At: STP, Wadsworth, Matagorda County, Texas Inspection Conducted: May 24 through June 14, 1993 Inspectors: L. E. E11ershaw, Reactor Inspector, Maintenance Section Division of Reactor Safety C. J. Paulk, Reactor Inspector, Engineering Section Division of Reactor Safety Approved: id [, s# 07/23/f3 Dr. Dale A. Powers, Chief, Maintenance Section Date Division of Reactor Safety i I
Inspection Summary Areas Inspected (Units 1 and 21: Reactive, announced onsite inspection of events pertaining to the licensee's notification regarding a normally closed main feedwater isolation bypass valve being discovered partially open, and a notification of a failure to maintain the equipment qualification o residual heat removal motor-operated valv Results (Units 1 and 21:
- The licensee did not appear to have fully evaluated the cause for the incorrect location of the local valve position indicator prior to attempting to make corrections (Section 2.1.2).
- Licensee investigation determined that the main feedwater isolation bypass valve had not been partially open as originally reported; however, the historical positions of main feedwater isolation bypass valves could not be determined (Section 2.1.2.2).
9307300177 930723 ""7 PDR ADOCK 05000498 h<
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- An unresolved item was identified when an instrumentation and controls technician attempted to perform an independent verification activity that was not specified in the work request (Section 2.1.2.1).
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- The lack of procedural requirements during maintenance to document (1)
retorquing of stem clamp bolts subsequent to any activity that required i their loosening, and (2) occurrences in which local valve position indicator readings were considered to be different from remote valve position indicator readings, were considered to-be programmatic weaknesses (Section 2.1.2.2).
- An unresolved item was identified with respect to the licensee failing to calibrate valve remote position indicators as required by the inservice test program (Section 2.1.2.3).
- An unresolved item was identified regarding the licensee's reclassification of the main feedwater isolation bypass valve positioners to a nonsafety-related status (Section 2.1.2.4).
- A result of the reclassification was the expiration of the environmental qualification life of the Unit 1 positioners (Section 2.1.2.4).
- An unresolved item was identified with respect to the licensee's implementation of corrective action after they recognized the significance of the positioners' reclassification (Section 2.1.2.4). '
- The licensee deactivated preventive maintenance activities on the safety-related main feedwater isolation bypass valves (Section 2.1.2.5).
- An unresolved item was identified regarding the licensee's review of design documents and assumption that the safety-related solenoid valves for the main feedwater isolation bypass valves were normally deenergized. This possibly resulted in a failure to maintain the solenoid valves' environmental qualifications (Section 2.1.2.6).
- An unresolved item was identified regarding the licensee's failure to :
maintain the motor operator for the Unit 2 Residual Heat Removal B train suction valve in a configuration supported by test results ,
(Section 2.2.2).
- A programmatic weakness was identified in that a requirement for the )
inspection of T-drains and grease reliefs was not specified to be l performed during inspections of motor operators (Section 2.2.2).
- Poorly written descriptions of work performance were identified as a generic weakness in the work control process (Section 2.2.2).
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Summary of Inspection Findinas:
- Unresolved Item 498/9319-01; 499/9319-01 was opened for NRC review (Section 2.1.2.1).
- Unresolved Item 498/9319-02; 499/9319-02 was opened for NRC review (Section 2.1.2.3).
- Unresolved Item 498/9319-03; 499/9319-03 was opened for NRC review (Section 2.1.2.4).
- Unresolved Item 498/9319-04; 499/9319-04 was opened for NRC review (Section 2.1.2.4).
- Inspection Followup Item 498/9319-05; 499/9319-05 was opened (Section 2.1.2.5).
- Unresolved Item 498/9319-06; 499/9319-06 was opened for NRC review (Section 2.1.2.6).
- Unresolved Item 499/9319-07 was opened for NRC review (Section 2.2.2).
Attachment:
- Persons Contacted and Exit Meeting
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-4-i DETAILS 1 PLANT STATUS Unit I was in Mode 5, and Unit 2 was defueled and in no mode during this inspection perio ONSITE REVIEW OF LICENSEE EVENT REPORTS (92700)
2.1 Main Feedwater Isolation Bypass Valve 2. Licensee Notification .
On April 22, 1993, the licensee made a 24-hour notification (EN No. 25434),
which identified that a violation of Technical Specification 3.7.1.7 had occurred in that a Unit 2 main feedwater isolation bypass valve (B2FW-FV-7146A), which should be normally closed, had been open approximately 25 percent for the period between April 25, 1992, and February 3, 199 .1.2 Discussion April 25, 1992, was established by the licensee as being the date from which the valve was suspected of being partially open based on the valve's failure to stroke full closed during the performance of a surveillance procedure on that day. After corrective maintenance was performed on Service Request (SR)
FW-164222 dated April 25,1992 (i.e., replacement of valve positioner gauges),
operations stroked the valve from the control room, but the red closed indicator light would not illuminat It was determined that the limit switch for the closed indication was out-of-adjustment, so maintenance adjusted the valve closed limit switch. Operations then stroked the valve from the control room and verified that the open and closed indicator lights were operatin ,
Subsequently, during a routine Independent Safety Engineering Group (ISEG)
surveillance activity on August 4-5, 1992, an ISEG engineer noted in his "ISEG Field Notes - Inspection of Flow Controllers for the FWIV Bypass Valves" that ,
Main feedwater Isolation Bypass Valve B2FW-FV-7146A appeared to be '
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approximately 25-30 percent open as shown by the local valve position-indicator. The ISEG engineer contacted the control room and was informed that the valve was indicated to be closed. The ISEG engineer concluded and documented in his report, that, "Apparently, the valve has been ' adjusted in !
the past and its valve position indication scale not modified. Although the l scale has been marked with a pencil to show the new closed position, the scale ;
should be corrected." The ISEG engineer also stated in his report that the j process flow controller (located in the process line upstream of the valve)
indicated that the valve was shut. He also recorded that three of the other seven station flow control indicators (4 per reactor) for their respective main feedwater isolation bypass valves showed flow = associated with 8 to 62 inches of water column differential pressure. The ISEG initiated SR FW-165146 on August 6,1992, which stated that the valve position indicator was ,
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on August 6,1992, which stated that the valve position indicator was partially open with the valve shut and that the position index (stroke) plate needed to be relocated upwards, cutoff, or painted to remove the lower line I The inspector's review of calibration data sheets for sace of the flow control indicators indicated that it was not unusual for a flow control indicator to show a positive water column differential pressure in the as-found condition, even though it was known that there was no flow in the lin ^
The inspector requested the licensee to provide the document (s) upon which their understanding was derived for the valve position indicator being incorrectly located, and the procedure or instructions established for accomplishing any adjustments to local valve position indicators. The inspector was informed that such documents did not exis .1. Initiation of Corrective Maintenance -
On April 8,1993, an instrumentation and controls technician was assigned to perform the tasks described in SR FW-165146. Before moving the stroke plate, !
the technician loosened the stem clamp and attempted to rotate the valve stem 1 to verify its position (either open or closed). These actions were not specified in the SR, and wer: possibly contrary to Procedure OPGP03-ZA-0090, i
" Work Process Program," Revision !
Following these actions, there was a sudden movement and the technician noted l that the valve position indicator was now aligned with the stroke plate and
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showed a closed position. The technician manually actuated the positioner and exercised the valve from fully closed to fully open several times. It )
appeared that the positioner and valve were operating correctly. This caused 1 the technician to assume that the valve stem had been mechanically bound and when the attempt to rotate the valve stem was made, it became unbound and moved from the as-found partially open position to the fully closed positio This resulted in the initiation of Station Problem Report (SPR) 93122 on April 8, 1993, and notification being made to the NR The inspector considered this verification activity by the technician to be poor practice and the consequence could have been an unauthorized valve position manipulation. The matter of an independent verification by valve manipulation being performed without authorization is an unresolved item (498/9319-01; 499/9319-01) requiring further NRC revie .1. Investigation of Valve Position !
The inspector requested failure histories on the main feedwater isolation bypass valves. The inspector determined that Valve B2FW-FV-7146A had failed approximately 35 percent open after a reactor trip on January 10, 1991. A more recent and similar example occurred during the reactor trip on February 3,1993, in which similar Valve A2FW-FV-7148A-failed approximately 30 percent open. The licensee determined that both instances were caused by the valve positioners being out-of-calibration as a result of their zero
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-6-C adjustment locknuts having vibrated loose, which in turn allowed the zero adjustments to drift. The valve positioner is mounted to the valve actuator subassembly, and serves to provide local indication of valve positio Subsequent to the April 22, 1993, 24-hour notification, the licensee determined that the valve had not been open. The licensee's investigation consisted of a valve diagnostic test performed by Fisher Diagnostic Services prior to valve disassembly, and inspection by the licensee and Valtek (the valve manufacturer) personnel. The Fisher diagnostic test was performed on May 22, 1993, and the following results were noted in the test report. The valve stroke travel (seat to backseat) was measured as 1.627 inches compared to the specified 1.5 inches. The report recommended adjustment to shorten the stroke. The report also noted that the top limit switch was not tripping and the bottom limit switch was tripping early. The positioner data indicated a variance between specified and measured parameters and a bench inspection or overhaul was recommende The Valtek report, dated May 27, 1993, concluded that the valve was closed on April 8, and when the stem clamp was loosened by the technician, the spring pressure forced the threaded actuator stem down over the threaded valve stem, which appeared to the technician as valve travel. This was evident by the damage to the threads, which was observed by the inspector. The inspector did not observe any other physical damage or evidence to indicate that the valve had been mechanically bound, or in any way restrained from operating as it was intended. The damage to the threads supported the conclusion and secounted for the movement noted by the technician at the time he tried to rotate the valve stem after loosening the stem clamp. The inspector concluded that the
- most likely cause of this incident would have been either (1) an incorrect i adjustment of the stem to the closed position of the stroke indicator plate at the time the stem clamp bolting was tightened and/or-(2) incorrect valve stem to actuator stem engagement. The licensee indicated that it was possible for the valve stem to back out of the actuator stem considering the amount of vibration that the valve experienced while in the open position (brief periods !
during plant startup). However, this should be possible only if the stem clamp had not been properly tightene A review of valve maintenance controls noted that there was no requirement for the licensee to document the retorquing of the stem clamp bolts subsequent to !
any activity that required their loosening. In addition, there was no requirement for technicians or operators to document occurrences in which local valve position indicator readings were found to differ from the remote position indicator readings. The lack of these two procedural requirements were considered to be programmatic weaknesse l Licensee personnel could not categorically state that the position of main feedwater isolation bypass valves was readily apparent at all times. Such uncertainty was partially the result of the inaccurate readings from flow-control indicators and the Lislocation of the local valve position indicato i
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2.1. Inservice Test (IST) Program The inspector reviewed Revision 3 to the licensee's IST program, dated ,
December 20, 1990, to verify that-the main feedwater isolation bypass valves were included in the IST program and to determine applicable tests, test frequencies, and any specific requirements pertaining to these valves. The licensee had classified the subject valves as Category B valves and specified that the valves be full-stroke exercised for operability at least once every 3 months (except when the other train (s) of a redundant system were inoperable), and that stroke-time measurements be taken and compared to the stroke-time limiting values specified in Article IWV-3410 in Section XI of the ASME Boiler and Pressure Vessel Cod In addition, the IST program stated that the remote valve position indicators were to be used during full-stroke exercising and must, therefore, be calibrated at least once every 2 rear The inspector requested the licensee's records of full-stroke exercising and stroke-time results to review compliance with frequency and action requirements. The inspector found that no records were available to show that calibration of remote valve position indicators had ever been performe Discussion with the Section XI (IST) coordinator and the plant engineering :
supervising engineer resulted in the inspector being made aware of SPR 930762, '
dated March 10, 1993, in which this problem had been identified by a quality assurance staff specialis In response to the SPR, plant engineering performed an operability and reportability review dated March 11 and 16, 1993, which concluded that the problem did not affect operability nor was it reportable. The response stated that Section XI of the ASME Code did not require calibration of remote position indicators, but rather, it required observation at least once every 2 years to verify that valve operation was accurately indicated. The response further stated that there was an error in the wording of the definition in the IST program plan (i.e., calibration versus verification) and it would be corrected to reflect Section XI requirements in the next revision to the IST program plan. The response concluded that verification has been performed at least once every 2 years; therefore, operability of components subject to remote position indicator requirements was not a concer The inspector verified that a procedure existed which addressed verification of indicator accuracy of val"e operations. Procedure OPSP03-ZG-0002, " Valve Remote Position Indicator Verification Test (Cold Shutdown)," Revision 0, dated February 28, 1992, provided the fastructions to perform verification of indicator accuracy for those indicators which could not be locally observed during power operations. The inspector verified that the main feedwater isolation bypass valves were specifically identified in the procedure and that the procedure had been implemented, as evidenced by review of completed verification data packages dating back to 198 It should be noted that, initially, each unit had its own procedure (i.e., Unit 1, Procedure 1-0 PSP 03-ZG-0002; and Unit 2, Procedure 2-0 PSP 03-ZG-0002). Both procedures had the same requirements and identified the valves unique to the uni During a procedure reduction and consolidation effort, the two
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L individual procedures were combined and superseded by the current single procedur The inspector concluded that the licensee appeared to meet the requirements of the ASME Code for stroke testing, which is required by Technical-Specification 4.0.5. However, compliance with the IST program plan regarding f calibration of remote position indicators could not be confirmed. This matter ;
is an unresolved item (498/9319-02; 499/9319-02) requiring further NRC revie l The inspector requested procedures that pertained to setup and calibration of '
control valves and positioners and was informed that Procedure OPMP08-ZI-0025,
" Pneumatic / Spring Control Valve or Damper Calibration," Revision 3, dated !
December 23, 1992, was the established procedure for this activity, and that ,
it was generic and had been developed as a preventive maintenance documen The inspector noted that Section 4.4 stated that manufacturers' literature may .
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be referred to for detailed calibration instructions, however, if used, the manual number and section numbers must be recorded in the remarks section of the appropriate pages on the attached forms. At least five other steps -
throughout the procedure (Step 7.3.5, stroke adjustment; Step 7.4.2, bench set ,
adjustment; Step 7.5.4, positioner adjustment; Step 7.7.3, position switch adjustment; and Step 7.8.4, position transmitter calibration) referenced the i use of manufacturers' literatur ;
The inspector requested the completed data package showing the last implementation of Procedure OPMP08-ZI-0025 on a main feedwater isolation bypass valve and was provided with a completed calibration data package for i Main Feedwater Isolation Bypass Valve B1FWFV7145A, which showed that the work l had been performed and the valve returned to service on February 24, 198 l The inspector noted that the remarks section on the applicable pages did not reference the use of vendor / manufacturer literature. However, Manual N BYT was identified in the package as being the manual used to perform the work. The licensee explained that the manual was a licensee assembled document, which was identified with numbers signifying purchase order and equipment designation. The "B" referred to manual revision and "VT" was the code assigned to the manufacturer (i.e., Valtek). The inspector's review of the manual revealed that all of the Valtek maintenance bulletins were part of the manual; therefore, the inspector concluded that the licensee, while not annotating the use of vendor literature, had demonstrated that the pertinent vendor information was available for use at the time of setup and calibratio .1. Valve Positioners During the licensee's review of the problem associated with out-of-calibration positioners caused by loose zero adjustment locknuts, it was identified and documented in SPR 931818, dated May 21, 1993, that the valve manufacturer's seismic / environmental qualification report required replacement of sensitive parts every 4 years in order to achieve a 40-year design life. The SPR also ;
identified that the positioners had been classified as nonsafety-related, when i in fact, they performed a safety function; and preventive maintenance !
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l activities had not been performed on the positioners. The design was such that upon receipt of an engineered safety features actuation signal, the !
positioners were required to vent air from the main feedwater isolation bypass valves in order to assure valve closure. The inspector reviewed a Bechtel l
Energy Corporation (the architect-engineer) memorandum (IDH 44469) dated i September 10, 1986, which stated that " pneumatic positioners are non-safety." '
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There was no basis provided for this statement; however, the licensee reclassified (at some unknown time in late 1986) the main feedwater isolation bypass valve positioners in the mechanical equipment qualification list to
"non-safety."
Subsequently, on June 12, 1989, plant engineering initiated engineering change notice packages (ECNP 89-J-0164 for Unit I and ECNP 89-J-0165 for Unit 2), i which identified that the main feedwater isolation bypass valves were subject to failure due to the nonsafety-related positioners being required to perform '
a safety-related functio Since the positioners had been reclassified from safety to nonsafety-related items, actions had not been established or i performed to ensure their ability to function as require j Criterion III of Appendix B to 10 CFR 50 requires that licensees assure that the applicable design basis for components that prevent or mitigate the :
consequences of postulated accidents are correctly translated into specifications, procedures, and instructions. The licensee's reclassification of the positioners is considered an unresolved item requiring further NRC l review (498/9319-03; 499/9319-03). ,
The inspector reviewed Valtek's report, " Design Report No. 34753/52-14, -15,
-16, -17, Seismic / Environmental Qualification Report of Automatic Control l Valves," Revision 2, dated October 23, 1985. This report represented a ,
seismic / environmental qualification analysis of the Valtek automatic control l valves (i.e., main feedwater isolation hypass valves) and included the l appropriate certifications. The report also contained a statement of j qualified life, which stated that age-sensitive parts (i.e., 0-rings, boots, and diaphragms) in the positioners must be replaced every 4 years and that this maintenance interval must be observed in order to achieve a 40-year life (based on a maximum continuous operating temperature of 300' F). Valtek Report TT-34752, " Thermal Aging And Accidental Temperature Testing Of Mark One And Valdisk Valves," Revision 3, dated April 21, 1987, recommended that the replacement interval be every 5 years based on a maximum continuous operating temperature of 212* F for the main feedwater isolation bypass valve positioners. As a result of the misclassification to nonsafety-related status, the age-sensitive parts had not been replaced, thus, the qualified life for the Unit 1 main feedwater isolation bypass valve positioners had I expired on June 6, 1992. This date was based on the date the equipment was turned over to operations from the startup organization which was June 6, 1987. The qualified life of the Unit 2 positioners had not yet expired, since these had not been turned over to operations until December 9, 1988. The licensee reviewed other safety-related valves with positioners to determine whether similar concerns existed. The results of the review were addressed in a document dated May 25, 1993, which stated that only Valtek valves that used
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positioners and solenoid valves were involved. While the document did not provide valve identification, the inspector was informed that a group of 12 chilled water valves was identified with a similar configuration; however, '
these valves were not located in a harsh environment and no periodic replacement of age-sensitive parts was required to maintain the qualification Plant engineering initiated ECNPs 89-J-0164 and 89-J-0165 on June 12, 1989, for Units 1 and 2, respectively. These documents clearly show that engineering was cognizant of the safety-related versus nonsafety-related issues. The suggested change noted on the ECNPs was to, " Redesign as required to ensure valve closure on actuation of the safety solenoids, independent of the positioner." The assigned priority was shown to be B4.0, which apparently ,
resulted in no actions being performed until May 22, 1993, at which time the design change was implemented for Unit 1 on a modification work order authorized by SR 16874 The licensee committed, during the preliminary exit on May 28, 1993, to implement the same design change for Unit 2 prior to reaching Mode 3, at which time the Technical Specification associated with the main feedwater isolation bypass valves would become applicable. The existing document, used to establish priorities at the time the ECNPs were originated, was a single page guide showing categories, each with various numbered steps ranging from 1 to 5, with I being the most critical. The assigned priority B4.0 was defined as follows: Category B referred to plant operations and Step 4.0, which fell '
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between Step 3.5 defined as meaning if the design change did not occur then there was a 10 percent chance that the plant would go to Mode 3 within 1-year, and Step 4.5 defined as a low risk to system operation. Criterion XVI of Appendix B to 10 CFR 50 requires that licensees promptly correct identified conditions adverse to quality. This deficiency is considered an unresolved -
item (498/9319-04; 499/9319-04) requiring further NRC revie .1.2.5 Preventive Maintenance The inspector reviewed licensee Office Memorandum ST-P2-HS-1301 dated November 15, 1988, which deactivated preventive maintenance activities ;
classified as Priority Levels 2C through 3D. The deactivation was to be "a short-term effort to more effectively utilize manpower on Units 1 and 2 corrective maintenance and finalize PM (preventive maintenance) development of Priority 1A through 28." The inspector determined through review of documentation, that the main feedwater isolation bypass valves had been classified as Priority 3A. Attached to the memorandum was Addendum 1 to Procedure OPGP03-ZM-0002, " Preventive Maintenance Program," Revision 16, which~
was in effect at that time. The addendum defined the bases for establishment of priority levels. The first character of the priority level defined equipment importance, with the Character 3 meaning equipment that was not safety-related and, if lost, would not affect power generation of the plan The second character defined the importance of the preventive maintenance activity to the equipment, with Character A meaning that the preventive ,
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-11-maintenance activities were required to maintain equipment qualification or regulatory requirement The inspector reviewed several other documents (i.e., ST-P2-P2-418 dated April 11, 1989; ST-HS-P2-1225 dated October 12, 1989; ST-HS-HS-14126 dated January 17, 1991; ST-HS-HS-14215 dated February 7, 1991; and ST-HS-HS-14457 dated March 18,1991), all dealing with deactivation of preventive maintenance activities pertaining to the main feedwater isolation bypass valves and their ancillary equipment. The inspector requested and was provided a preventive maintenance history for the eight main feedwa^er isolation bypass valves (four per unit). A computer printout that was gen.ated on May 27, 1993, showed the following:
- Unit 1 B1FW-FV-7145A and BIFW-FV-7146A, six activities performed on each between March 13, 1987, and February 24, 1989; AIFW-FV-7147A, six activities between March 13, 1987, and February 23, 1989; and AIFW-FV-7148A, five activities between March 13, 1987, and January 25, 198 * Unit 2 B2FW-FV-7145A, three activities between September 14, 1988, and April 26, 1989 ,
A2FW-FV-71'47A, three activities between September 18, 1988, and July 12, 1989; and A2FW-FV-7148A, two activities on September 18, 1988, and April 27, 198 There were no entries for Unit 2 Valve B2FW-FV-7146A. The inspector did not identify any correlation between the two incidents where the valves failed open after a reactor trip (B2FW-FV-7146A on January 10, 1991, and A2FW-FV-7148A on February 3, 1993) and the respective nonperformance of preventive maintenance and cessation of preventive maintenance activities as of April 27, 198 The inspector was provided a copy of SPR 931759, which had been initiated on May 18, 1993, by a quality assurance staff specialist, that addressed the lack of preventive maintenance being performed on the main feedwater isolation bypass valves and positioners. The inspector identified this concern related to the lack of sufficient bases for deactivating preventive maintenance activities as an inspection followup item (498/9319-05; 499/9319-05).
2.1. Equipment Qualification of Solenoid Valves During review of the documents dealing with deactivation of preventive maintenance discussed above, the inspector noted that Office
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-12-Memorandum ST-HS-HS-14457 dated March 18, 1991, extended the qualified life of numerous safety-related solenoid valves, including the 16 solenoid valves associated with the main feedwater isolation bypass valves (2 safety-related solenoid valves per bypass valve), from 4 to 40 years. As noted later, the licensee performed additional calculations and preliminarily determined the qualified life to be 2.5 years. The memorandum further stated that all approved corresponding preventive maintenance activities for end-of-life parts replacement were to be deactivated. The inspector reviewed the licensee's computation sheets for Calculation E-89-ASCO, which dealt with a qualification extension to 40 years for ASCO solenoid valves. Attachment 2 to the calculation, dated December 7,1989, established the bases for the extensio The Attachment concluded that the solenoid valves were normally deenergized and were energized only when their associated main feedwater isolation bypass valves were open (i.e., during main feedwater system heatup operations). The computation sheet stated that for solenoid valves installed in a normally de-energized configuration, thermal aging is not a limiting condition since heat rise due to an energized coil is not a factor; therefore, these solenoid valves have a thermal qualified life of 40 years as documented in the equipment qualification calculation package. The inspector noted during review of the Valtek design report mentioned above, that the " Statement of Qualified Life" also pertained to the ASCO solenoid valves associated with the main feedwater isolation bypass valves. The " Statement of Qualified Life" addressed the need for replacement of the solenoid coils and elastomeric -
components every 4 years, and that this must be performed in order to achieve a 40-year lif This apparent conflict resulted in the licensee initiating SPR 931881 on May 28, 1993, which stated that the main feedwater isolation bypass valve solenoids had exceeded their qualified life. The inspector reviewed Main Feedwater Isolation Bypass Valve Logic Diagram 5S-13-9-Z-40121, No.1/No. 2, Revision 5, dated May 25, 1988, and noted that the safety-related solenoid
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valves were normally energized. Based on Valtek's design report and the start of qualification life (Unit 1, June 6,1987; and Unit 2, December 9,1988),
the qualifications of the safety-related solenoid valves expired on June 6, 1991, and December 9,1992, respectivel The licensee's assumption resulted in a condition in which the solenoid valves, which were on the equipment qualification list and subject to 10 CFR 50.49 requirements, were neither refurbished nor replaced;. thus, their qualified life may have been exceeded. This failure to maintain the environmental qualifications of electrical equipment is an unresolved item (498/9319-06; 499/9319-06) requiring further NRC revie ,
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2.1.2.7 Technical Specification Requirements Technical Specification 3.7.1.7 requires each main feedwater isolation valve to be operable during Modes 1, 2, or 3. The Technical Specifications do not, however, explicitly address the main feedwater isolation bypass valves. As l discussed on page 16.1-14 of the Updated Final Safety Analysis Report, the j main feedwater isolation valve requirements apply to the main feedwater l
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-13-isolation bypass valves (i.e., the main feedwater isolation bypass valve operability is necessary in order to satisfy the functional requirement of the Technical Specification for the main feedwater isolation valves). The main feedwater isolation bypass valves exceeded their qualified lives (Unit 1, solenoid valves on June 6, 1991, and positioners on June 6, 1992; Unit 2, solenoid valves on December 9,1992). Technically, a potentially degraded condition existed for the main feedwater isolation valve During the lice 1see's continuing evaluation, it was identified that the preheater bypass valves and the main steam isolation bypass valves were similarly affected (i.e., an erroneous assumption was made resulting in an extended qualified life). The licensee recalculated the qualified lives of the corresponding solenoid valves. The preliminary results showed that the qualified life of the preheater bypass solenoid valves and the main steam isolation bypass solenoid valves has been reduced from 40 years to 9.93 year While this is a considerable reduction, at the time of the inspection these valves had not exceeded their qualified live Following this inspection, the inspector was informed by the licensee that a preliminary recalculation of the qualified life of the main feedwater isolation bypass solenoid valves had determined that the qualified life for the solenoid valves should be 2.5 years rather than 4 year .1.3 Conclusions Licensee investigation determined that the main feedwater isolation bypass valve had not been open as originally reported. Licensee personnel could not categorically state that the position of main feedwater isolation bypass valves was readily apparent at all time The licensee did not appear to have fully evaluated the cause for the incorrect location of the local valve position indicator prior to attempting to make corrections. An unresolved item was identified with respect to the licensee's calibration of valve remote position indicators as required by their inservice test program. In addition, the program lacked procedural requirements to document (1) retorquing of stem clamp bolts subsequent to any activity that required their loosening, and (2) occurrences in which local valve position indicator readings were different from remote position indicator readings. These latter two issues were considered to be weaknesse An unresolved item was identified pertaining to the attempt by an instrumentation and controls technician to perform an independent verification activity that was not specified in the work request. The performance of work activities not prescribed in written instructions was considered to be poor practic An unresolved item was identified regarding the licensee's reclassification of the main feedwater isolation bypass valve positioners to a nonsafety-related status. A result of the classification was the expiration of the environmental qualification life of the Unit 1 positioners. An unresolved e
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l item was identified with respect to the licensee's corrective action after l they recognized that the positioners had been incorrectly classifie i
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The licensee deactivated preventive maintenance activities on the main i feedwater isolation bypass valves and none has been performed since July 1989. I This was not considered an approprlate action to be taken for safety-related i equipment. This issue was identified as an inspection followup ite l, An unresolved item was identified regarding the assumption that the safety-related solenoid valves for the main feedwater isolation bypass valves were i normally deenergized. This may have resulted in the failure to maintain the l solenoid valves' environmental qualifications. It appeared that the assumption was based on inadequate review of design document .2 Licensee Event Report 93-08 2. Licensee Notification During a recently conducted NRC diagnostic evaluation, an NRC inspector found that the motor operator for the Unit 2 Residual Heat Removal B Train Suction Valve B2RHMOV0060B did not have a T-drain installed. Subsequently, the licensee made a 24-hour notification (EN No. 25495) to the NRC on May 5, 1993, l and issued Licensee Event Report 93-08 on June 4, 1993. The 10 CFR 50.73 '
notification stated that a violation of the Technical Specifications (unspecified number) had occurre .2.2 Discussion l Title 10 CFR 50.49(f) requires, that, "[e]ach item of electric equipment important to safety must be qualified by . . . [t]esting an identical item of ,
equipment under identical conditions or under similar conditions with a :
supporting analysis to show that the equipment to be qualified is acceptable."
The licensee determined, from a review of SR RH-70405, that the T-drains had been inadvertently omitted during maintenance activities in November 199 l The licensee then initiated SPR 931578 on May 5, 1993, to address the missing !
T-drains. The failure to install T-drains on motor-operated valves located in :
harsh environments resulted in the use of non-qualified equipment. This !
matter is an unresolved item for further NRC review (50-499/9319-07). ,
l During this inspection, the inspector found that the licensee had performed an i inspection of all motor-operated valves located in areas that would be subject I to a harsh environment when required to operate during a design basis event; ;
reviewed the work history data base for activities associated with motor replacements on motor-operated valves; and, reviewed approximately 3000 SRs for the proper determination of operability and non-conformance identification. The licensee concluded from these reviews that the impact of lack-of-knowledge of the requirements of equipment qualification, coupled with associated work practices and procedural problems, had resulted in occurrences that impacted equipment operability. This conclusion was found in the licensee's draft response to SPR 931524, which was initiated April 30, 199 l l
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-15-The inspector performed visual inspections of a sampling of motor-operated valves, transmitters, and solenoid-operated valves located in harsh environments for the installation of T-drains, grease reliefs, conduit seals, and mounting, as required. The inspector did not identify any discrepancies with any of the component The inspector also reviewed the SRs that the licensee had reviewed because motor or actuator replacement was involved. The inspector asked if other environmental qualification attributes had been evaluated by document revie The licensee stated that, based on the programmatic review, such a review was not previously considered to be necessary. Nevertheless, the licensee promptly initiated a review of a sample of previous maintenance activities for other components required to be environmentally qualified (e.g., limit switches, solenoid valves, and transmitters). The licensee did not identify any instances where maintenance activities would have affected qualification of the component The inspector noted that the craft person who performed work on the seal water injection isolation valve to Reactor Coolant Pump ID B1CVM0V0033D under the guidance of SR CV-177328 found, on November 5, 1992, evidence of a mixing of limit switch gear housing grease (Mobil 28) with actuator grease (Nebula EPO)
and also identified the stem nut locknut was loose. The inspector interviewed this person and found that there was evidence of the Mobil 28 grease in the drive sleeve area. The person also stated that he remembered that he had found "a valve" in the same general area that had the locknut backed off approximately 0.635 cm (0.25 inches). The craft person stated that the grease was replaced and the locknut was staked in accordance with Procedure OPMP05-ZE-0304, Revision 4, "Limitorque Operator Removal and Installation," although the writeup in the package did not reflect those actions. The inspector considered the lack of detail in the documentation to have been a weakness in the work control process, as discussed belo In response to the questions raised concerning the staking of the stem nut locknut, the licensee initiated SPR 931865. The licensee commenced inspecting all safety-related and important to safety SMB-type motor-operated actuators that have stem nuts and had not been refurbished during the present outag The inspector reviewed 12 work packages that the licensee had identified as '
having replacement activities. The inspector found that poorly written descriptions of work performance was generic throughout the work packages reviewed. The poor descriptions contributed to the difficulties that the inspector and the licensee had in attempting to determine what activities were actually performed. The poor descriptions were directly responsible for the licensee's failure to identify the missing T-drains, and adversely affected the licensee's ability to evaluate trends or identify repetitive failure The inspector asked the licensee if any corrective action had been taken to address the potential consequences of poorly documented work performance. The licensee was unable to present any evidence that such actions had occurre The failure to take appropriate corrective actions for these issues occurred
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during the time period that was the subject of previous NRC findings (e.g.,
Violations 499/9304-02 and 499/9304-04) for which the licensee was cite Consequently, no further enforcement will be taken in response to this similar exampl i Although the licensee addressed T-drains in Addendum 6, motor removal and installation, to Procedure OPMP05-ZE-0300, Revision 13, "Limitorque MOV Motor Inspection and Lube," the inspector found that T-drains and grease reliefs were not required to be inspected during the inspection of the motor operato The absence of these inspections was considered a weakness in the procedur l 2.2.3 Conclusions l
The failure to install T-drains on Valve B2RHMOV0060B resulted in the use of non-qualified equipment and was identified as an unresolved ite Additionally, the lack of procedural steps to verify the installation of T-drains and grease reliefs was considered a weakness. The poorly written descriptions of work performance was identified as a generic weakness in the I work control process. The lack of sufficient detail in the work documents )
affected the licensee's ability to evaluate trends or identify repetitive l failures.
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ATTACHMENT I PERSONS CONTACTED 1.1 Licensee Personnel
- +C. Ayala, Supervising Engineer, Nuclear Licensing
- C. Bowman, Administrator, Corrective Action Group
- M. Chakravorty, Executive Director, Nuclear Safety Review Board ,
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- +K. Christian, Manager, Plant Operations
- +M. Coughlin, Senior Licensing Engineer
- F. Cox, Motor-0perated Valve Group
- T. Crawford, Supervising Engineer, Design Engineering Department
- K. Do, Rotating Engineer
- +E. Gilchrist, Staff Specialist, Instrumentation and Controls
- J. Groth, Vice President, Nuclear Generation
- G. Hales, Design Engineering Specialist
- M. Hardt, Director, Nuclear Division i
- +S. Head, Deputy Licensing Manager ,
- R. Helton, Senior Staff Specialist, Maintenance
+J. Johnson, Supervisor, Quality Assurance
- T. Jordan, General Manaaer, Nuclear Engineering
- W. Jump, General Manager, Nuclear Licensing
- R. Kersey, Design Engineer
- +D. Leazar, Manager, Plant Engineering ,
- J. Lodgerwood, Consulting Engineer
- J. MacKay, Planning and Assessment Engineer
- K. Hallen, Manager, Planning and Assessment
- T. Meinicke, Deputy Plant Manager
- D. Musick, Manager, Integrated Planning & Scheduling Work Control Center
- 4M. Pacy, Manager, Design Engineering Department
- J. Parish, Motor-0perated Valve Coordinator, Design Engineering
- +G. Parkey, Plant Manager
+ Parrish, Senior Specialist, Nuclear Licensing
- U. Patil, Supervising Engineer
- +R. Prater, Staff Specialist, Quality Assurance
- +S. Rosen, Vice President, Nuclear Engineering
- R. Schiavoni, Division Manager, Electrical, Instrumentation & Controls
- L. Taylor, Manager, Maintenance Planning
- +P. Travis, Supervising Engineering Specialist 1.2 NRC Personnel
- R. Evans, Resident Inspector
- D. Loveless, Resident Inspector, River Bend Station
- J. Tapia, Senior Resident Inspector In addition to the personnel listed above, the inspectors contacted other licensee employees during this inspectio * Denotes personnel attending the preliminary exit meeting on May 28, 1993.
- Denotes personnel attending the preliminary exit meeting on June 4,199 + Denotes personnel attending the exit meeting conducted by telephone on June 11, 199 .
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-2-2 EXIT MEETING Preliminary exit meetings were conducted on May 28 and June 4, 1993, during which the inspectors provided the status of inspection scope and finding During the preliminary exit meeting on May 23, 1993, the licensee committed to implement design change ECNP 89-J-0165 prior to Unit 2 restart, which would result in the main feedwater isolation bypass solenoid valves performing the !
safety-related valve venting function. The results of the inspection were ;
discussed during a final exit meeting conducted by telephone on June 11, 1993. i Additional information was discussed by telephone on June 14, 23, and 29, ;
1993. The licensee did not identify as proprietary, any information provided '
to, or reviewed by, the inspector ,
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