IR 05000321/1993014
| ML20056G808 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 08/30/1993 |
| From: | Thomas Scarbrough, Whitener H, Wiseman G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML20056G783 | List: |
| References | |
| 50-321-93-14, 50-366-93-14, NUDOCS 9309070190 | |
| Download: ML20056G808 (16) | |
Text
1
.
'
UtdlTED STATES
/ are%, . #
NUCLEAR REGULATORY COMMISSION l
i
~p* . .~$ REGION Il !
$ E 101 MARIETTA STREET. N.W. SUITE 2900 !
tii ;
y_ ATLANTA, GEORGtA 30323-0199
\e..../ !
Report Nos.: 50-321/93-14 and 50-366/93-14 ,
i Licensee: Georgia Power Company l
P. O. 1295 l Birmingham, AL 35201 l
Docket Nos.:- 50-321 and 50-366 License Nos.: DPR-57 and NPF-5 Facility Name: Hatch Nuclear Station Units I and 2 Inspection Conducted: July 26-30, 1993 l
Inspectors: .k IN hu ~
-
7 f 30/93 G. R. Wiseman Date Signed !
. A YT& YS l H. L. Whitener Date Signed ~ !
,
Accompanying l Personnel: T. Scarbrough ,
ting Ch f, est Programs Section l Eng ee pgBranch Div sion of Reactor Safety l '
ty, nsultant(E Idaho-INEL Approved y: . .c m b E 34 l . Vca oisgh, Acting Chief Dat'e Siijned l .Teit ograms Section Engin ring Branch Division of Reactor Safety l 1 :
I
'
SUMMARY l Scope:
This special, announced inspection was performed at the Hatch nuclear station .
l to ' examine the implementation of the licensee's motor-operated valve (MOV) 1 l program to meet commitments in response to Generic Letter (GL) 89-10, " Safety-l Related Motor-0perated Valve Testing and Surveillance." The inspectors utilized the guidance provided in Temporary Instruction (TI) 2515/109 (Part 2), " Inspection Requirements for Generic Letter 89-10, Safety-Related Motor-Operated Valve Testing and Surveillance." As delineated in Part 2 of TI i 2515/109, this inspection was the initial review of the implementation of the i licensee's MOV program in response to GL 89-10.
!
"
9309070190 930830 PDR ADOCK 05000321 G PDR
'
,
- m- ---- - ,
_ _ _ _ . _ _ ___ _ _ _ _ . __ .
.
The inspectors reviewed in detail six MOVs including selected portions of design calculations, test packages, and diagnostic signature traces. The inspectors also reviewed followup issues from the previous NRC inspection of the MOV program (TI 2515/109, Part 1) conducted in February 1992, and documented in NRC Inspection Report Nos. 50-321/92-04 and 50-366/92-0 Resul ts :--
Two violations of the NRC regulations and two Inspector Followup Items (IFIs)
were identifie Violation 50-321,366/93-14-01 resulted from the failure of the licensee to evaluate M0V test results. (Paragraph 2.3)
-
Violation 50-321,366/93-14-02 resulted from an instance where the I licensee had not evaluated the operability of an M0V when test results y revealed potential problems with the design-basis capability of the M0 ;
(Paragraph 2.3)
-
IFI 50-321, 366/93-14-03 was opened to identify the followup of the licensee's response to the Limitorque 10 CFR Part 21 notice on the adverse effect of high ambient temperature on ac motor outpu i (Paragraph 2.5)
-
IFI 50-321, 366/93-14-04 was opened to identify the followup of the actions taken by the licensee to address the potential for pressure locking and thermal binding of gate valves at Hatch. (Paragraph 2.7)
Weaknesses
-
The licensee's GL 89-10 Program Description (dated December 1992) did not reflect the findings of Inspection 50-321,366/92-04. (Paragraph 2)
,
-
The inspectors did not identify any concerns with the design-basis I reviews of the sampled MOVs. However, issues raised during the EDSFI (NRC Inspection Report Nos. 50-321 and 50-366/91-202) remain to be resolved. (Paragraph 2.1)
-
The inspectors did not identify any concerns with the methodology of the MOV sizing and setting calculations, but several assumptions have not been validated. (Paragraph 2.2)
-
The licensee had not demonstrated acceptability of its planned method for periodically verifying design-basis capability of MOVs within the scope of GL 89-1 (Paragraph 2.4)
-
The licensee had not formalized its method of trending MOV aroblem (Paragraph 2.5)
!
I i
l
l
,
.
,
}
I i
.The licensee had resolved only 5 of 18 concerns identified during the l GL 89-10 Part 1 inspection at Hatch in February 1992. (Paragraph 2.8) l t
!
Strenath i
-
The inspectors considered the MOV personnel at Hatch and the licensee's !
corporate office to be very skilled. Some of the licensee's personnel !
are involved to a significant degree in industry efforts to resolve i concerns about the performance _ of MOV (Paragraph 2.3) !
I i
)
i l
!
I l _ . . _ _ . _ . _ _ , . - - - _ . . . . _ _ . _ . . , . _ ~ _ _ . . . _ , . . , _ - . _ , . ._ .~.~,
,
'
.
l REPORT DETAILS Persons Contacted
- E. Burkett, Supervisor, Engineering Support
- P. Fornel, Manager, Maintenance i *G. Goode, Manager, Engineering. Support l *R. Flannigan, Manager, Nuclear Plant Engineering - Support l *M. Googe, Manager, Outages and Planning j *J. Graves, Motor-0perated Valve Maintenance Engineer l
- J. Hammonds, Supervisor, Regulatory Compliance
- J. Lewis, Manager, Plant Operations l *T. Metzler, Supervisor, Nuclear Safety and Compliance l *W. Mock, Motor-Operated Valve Test Coordinator
- T. Moore, Assistant General Manager
- J. Payne, Senior Engineer, Nuclear Safety and Compliance (NSAC)
l Other Oraanizations Southern Nuclear Operating Company (SNC)
- D. Atwood, Senior Engineer I, SNC
- 0. Fraser, Site Supervisor, Safety Assessment Engineering Review (SAER)
. Southern Company Services (SCS)
l l *M. Hoover, Motor-Operated Valve Engineer
- K. Ingram, Electrical Engineer
- C. Lynch, Motor-Operated Valve Senior Engineer
- L. McWhorter, Manager, Hatch Project Engineering Group l Other licensee employees contacted during this inspection included engineers, technicians, and administrative personne NRC Resident inspectors
- E. Christnot, Resident Inspector
- B. Holbrook, Resident Inspector
- Denotes personnel that attended the exit meeting.
l Acronyms and initialisms used throughout this report are listed in the
- last paragrap . GENERIC LETTER (GL) 89-10 " SAFETY-RELATED MOTOR-OPERATED VALVE [M0V)
TESTING AND SURVEILLANCE" (2515/109)
i On June 28, 1989, the NRC issued GL 89-10, which requested licensees and construction permit holders to establish a program to ensure that switch settings for safety-related MOVs were selected, set, and maintained properly. Subsequently, five supplements to the GL have been issued plus one issued for comment. NRC inspections of licensee actions implementing commitments to GL 89-10 and its supplements have been
._
'
.
conducted based on guidance provided in Temporary Instruction (TI)
2515/109, " Inspection Requirements for Generic Letter 89-10, Safety-Related Motor-Operated Valyc Testing and Surveillance."
TI-2515/109 is divided into Part 1, " Program Review," and Part 2,
" Verification of Program Implementation."
The TI 2515/109 Part 1 program review was conducted at Hatch on February 24-28, 1992, and is documented in NRC Inspection Report 50-321,
-
366/92-04. A written response was requested to clarify the licensee's commitments concerning program schedule and testing requirements. The licensee provided its response on July 2, 1992, and the NRC staff replied on October 21, 1992. Other programmatic concerns (no written response requested) were addressed during this inspectio The princ@l focus of this inspection was to select and review in depth several MOVs from the 134 and 157 safety-related MOVs within the GL 89-10 program for Hatch Units 1 and 2, respectively. The selection was based on an information matrix provided by the licensee in response to a request by the inspectors. The selection was made to sample various systems, valve sizes, and differential pressure conditions, to the extent practicabl For the MOVs selected, the inspectors reviewed the licensee's Generic Letter 89-10 M0V Program Description (December 1992), piping and instrumentation drawings, the design-basis calculation results of the expected differential pressure, the sizing and switch setting calculation, the diagnostic test data package, and the diagnostic traces using VOTES 2.3 softwar The following MOVs were selected for review:
1 Ell-F015A - Residual Heat Removal (RHR) Inboard Injection IEll-F028A - Residual Heat Removal Torus Spray Train A Outboard IE11-F0288 - Residual Heat Removal Torus Spray Train B Outboard IE21-F005A - Core Spray Inboard Injection IE21-F031B - Core Spray Minimum Flow Bypass Isolation 2E51-F045 - Reactor Core Isolation Cooling (RCIC) Steam Supply Five of the MOVs reviewed were gate valves and one MOV was a globe valve. These MOVs were configured as shown below:
l l Valve N Actuator Closure Control Valve Size (inchesl I and Tvoe IEll-F015A SB-3 TORQUE 24 Gate IE11-F028A SB-2 TORQUE 16 Gate IE11-F028B SB-2 TORQUE 16 Gate
_- -_ _ -. _ , _ _ . _ - . - - . - - - _ __
~
.
l
l IE21-F005A SB-2 TORQUE 10 Gate l IE21-F031B SMB-000 TORQUE 3 Gate 2E51-F045 SMB-0 TORQUE 4 Globe The inspectors concluded that the licensee's implementation of its MOV program appeared to address adequately some of the GL 89-10 l recommendations and the licensee's commitments to the generic lette However, the inspectors identified significant deficiencies in the licensee's testing of MOVs and the evaluation of test data. The inspectors indicated that the licensee should review its GL 89-10 Program Description to assure that it addresses the issues raised in this inspectio .1 Desion-Basis Reviews The inspectors reviewed the licensee's calculations for determining design-basis differential pressure and flow conditions, design temperature, and other design parameters for each of the MOVs selected for review. As discussed below, the inspectors did not identify any concerns with the performance of the design-basis review for the sampled MOVs. Nevertheless, several issues remain to be resolved in response to the EDSFI report with regard to degraded voltag In 1989 and 1990, the licensee placed a contract with GE to develop a design-basis methodology to determine the differential pressure for accident scenarios for the RHR system. Subsequently, GE developed generic design-basis calculations for all GE-supplied safety-related systems. These generic calculations were promulgated by the BWROG and used initially at Hatch. Since then, the licensee has contracted with l Southern Company Services (SCS) to review the Hatch design-basis differential pressure and flow conditions for valve opening and closing for accidents, normal operation, shutdown, and test conditions. This l licensee review is in progress and scheduled for completion by the end i of 1993. Documents to be reviewed as part of this effort include the i FSAR, Technical Specifications, Plant System Procedures, Surveillance l
Procedures, Emergency Operating Procedures within the design basis for the plant, System Evaluation Descriptions, and P& ids. The inspectors reviewed the design-basis calculations for the sampled MOVs and did not identify any concern In the GL 89-10 Part I program inspection, the inspectors identified deficiencies in the licensee's performance of the ac motor degraded voltage calculations. Since then the licensee developed a degraded voltage calculation method that assumes 90 percent of nominal 600 VAC at the switch gear and then calculates circuit losses to obtain the voltage l at the motor terminals. The inspectors performed a sample degraded voltage calculation for an ac-driven MOV and did not identify any concerns with the licensee's voltage drop calculation. The inspectors noted that the deficiencies identified in the ac degraded voltage calculation during the GL 89-10 Part I program inspection (such as lack of consideration of TOL resistance and circuit resistance based on HELB accident taperatures) should be addressed for each applicable
!
~
_ __
f
ac-driven MOV in the Hatch GL 89-10 progra Further, the licensee should resolve the issues raised in the EDSFI report (such as degraded grid setpoint assumptions).
In the GL 89-10 Part 1 program inspection, the licensee's degraded voltage calculations for dc motors were considered a strength in that the licensee had identified certain system deficiencies and had issued design change-packages to correct these deficiencies. 'The inspectors performed a sample degraded voltage calculation for a dc-driven MOV and did not identify any concerns with the licensee's voltage drop calculatio .2 MOV Sizino and Switch Settina i
The inspectors reviewed the Generic Letter 89-10 M0V Program Description !
and the Hatch Motor-0perated Valve Torque Switch Setting Guide (Drawing l No. A-43830,-Revision D, February 18,1993) for the sampled MOVs. These documents included the program outline, MOV index and safety functions, results of design-basis calculations of thrust and torque values, and torque setting requirement l The inspectors discussed with licensee personnel the process for sizing MOVs and setting the switches. The licensee was using the Limitorque standard equation and design information to calculate the minimum thrust >
requirements for MOVs under degraded voltage conditions. The inspectors i did not identify any concerns with the methodology established to predict the thrust and torque required to operate the sampled MOV However, as discussed below, inspectors raised concerns regarding the assumptions for valve factor and stem friction coefficient, and the lack
,
'
of margin for load sensitive behavior (rate of loading) and stem lubrication degradation.
'
The inspectors reviewed the licensee's calculations for estimating the j thrust od torque requirements and establishing switch settings for the MOVs selected for review. The inspectors noted that the thrust requirements were adjusted to address diagnostic equipment inaccuracies (including torque correction factor) and torque switch repeatabilit In the report of the February 1992 inspection of the Hatch GL 89-10 program, the staff indicated its concerns regarding the assumptions for valve factor and stem friction coefficient and for the lack of margin for load sensitive behavior and stem lubrication degradation. During this inspection, the licensee continued to assume a 0.30 valve factor for all gate valves based on original valve vendor recommendations. As discussed in Paragraph 2.3, the inspectors found that the test results from the sampled MOVs did not support the licensee's valve factor assumption. Further, many industry tests of gate valves do not support the licensee's use of a 0.3 valve facto !
,
_ _ __-_ ______ __4
. - -. -.- . .- - - - _ - . _ _ _ _ _ _ - - ___ _
.
!
.
'
,
[
The licensee had assumed a stem friction coefficient of 0.15 for its :
M0Vs with a standard thre.:d configuration and a stem friction coefficient of 0.08 for MOVs using a ball-screw stem nut. The licensee i had not justified the assumption for stem friction coefficient based on evaluated, plant-specific test dat The inspectors noted that the licensee had not established margin in its ;
M0V thrust calculations to account for load sensitive behavior (rate of l loading) effects which can reduce the thrust output capability of an M0V l under dynamic conditions compared to its capability under static t conditions. The licensee should be able to justify the exclusion of f margin to account for load sensitive behavior. As indicated in '
Paragraph 2.3, the inspectors found that the sampled test results did not support the licensee's exclusion of margin for load sensitive l behavio The inspectors noted that the licensee had not established margin to account for stem lubrication degradation. Over a typical 18-month !
operating cycle, the grease applied to the valve stem may tend to harden ,
or become impregnated with dust or other debris. The overall effect is 1 to increase the stem friction coefficient-(and consequently stem factor) ;
resulting in less-thrust delivered to the stem for any given amount of 1-applied torque. The. licensee should be able to justify that the stem :
friction coefficient assumption used bounds the actual stem friction coefficient that will be observed throughout the lubrication interva The staff will evaluate the 1*censee's justification for its design I assumptions during future int tion .3 Desian-Basis Capability The licensee has identified 80 and 112 MOVs within its GL 89-10 program at Hatch Units I and 2, respectively, with active safety functions. At the time of the inspection, the licensee had conducted static testing of 76 and 62 MOVs at Units 1 and 2, respectively. The licensee considered 42 and 74 MOVs in Units 1 and 2, respectively, to be practicable to test under dynamic conditions. Of these MOVs, the licensee had conducted dynamic tests of 32 and 23 MOVs in Units 1 and 2, respectivel The inspectors reviewed the licensee test procedures and the static and dynamic test packages for the sampled MOVs. Also, the inspectors performed independent calculations to assess MOV capability and to determine whether the licensee assumptions were justified. Using the VOTES diagnostic software, static and dynamic traces were also evaluated by the inspectors. The results of this review are discussed belo The inspectors reviewed the test packages for the selected MOVs and observed that the dynamic test acceptance criteria were based on thrust i at control switch trip (CST) being within a specified thrust window, and l the successful completion of the valve stroke. Parameters such as flow and differential pressure were recorded on test data pheets. The l
, y ,,, - --- , ,-,~-.--w-..-._w --,--,,,_,,,--,,--_,,-,,.,r-,, .-,-r---,.
.
, t
- ,
i licensee indicated that the differential pressure values documented in '
the test packages would.later be adjusted for elevation differences and the inaccuracies associated with the pressure gage ,
The inspectors examined static and dynamic traces for the selected MOVs !
using the V0TES diagnostic software. The inspectors observed that the :'
licensee had not saved several traces with their selected marks to identify particular points in the traces. Marked traces are needed for i licensee analysis of the data. Therefore, the licensee does not have a record of the traces, as originally marked by the test technician when accepting the test as complet The inspectors noted that the sampled test data packages did not include i independent engineering review of the data. The inspectors learned that i the test data sheets were independently reviewed for completeness by !
personnel in the Document Control Center (DCC). However, this review did not verify operability of equipment or adequacy of test result The inspectors considered the acceptance criteria used prior to e returning tested MOVs to service to be inadequate. The licensee had not evaluated whether the test conditions required extrapolation of test ;
data to the specified design-basis conditions and had not performed such '
extrapolation as necessary. Instead, the licensee was relying on maximum system performance to justify design-basis capability. Section ,
8.3.4.3.1 of Hatch Administrative Control Procedure 50AC-MNT-008-0S i (Revision 2, April 20,1993), " Motor Operated Valve Maintenance and I Testing," requires that, for dynamic tests performed at less than design l basis flow / pressure, an evaluation of the M0V's performance at design l basis flow / pressure (projected) will be made. However, Procedures 34IT- l OPS-004-0S (Revision 1, April 26, 1993), " Dynamic MOV Testing," and 53IT-TET-002-0S (Revision I, March 12,1993), " Valve Operation Test and Evaluation System," do not ensure that test conditions are representative of design-basis conditions, or that test data are evaluated (including any appropriate extrapolation) to ensure that the tested MOV is operable Et design-basis conditions before the valve is returned to service. The inspectors performed a preliminary evaluation of the sampled gate valves and linearly extrapolated the thrust i
'
necessary to overcome differential pressure to design-basis condition '
For the gate valves sampled, the inspectors found that the test results at Hatch indicated that greater thrust is required to overcome dynamic conditions than predicted by the licensee. The inspectors identified two MOVs (IEll-F028A and IE21-F005A) with minimal margin at design-basis conditions relative to the current torque switch setting Section 8.6.1.1 of Procedure 50AC-MNT-008-0S requires the reconciliation of MOV test data results with assumptions in the design basis calculations. Procedures for such evaluations have not been prepared and some of the dynamic tests were over three years old. The inspectors also reviewed the selected dynamic test data using the industry standard equation, the valve port diameter, and dynamic test conditions to
, - 4 _ __ _ _ __ _ _ _
. _ . _ - _ - . -. _
5 determine each valve's apparent valve factor. The results of the review indicated valve factors greater '. nan the licensee's assumed valve factor of 0.30 for gate valves.
In response to the inspectors' concerns, the licensee performed an evaluation to determine the apparent valve factor of four gate valves (IEll-F015A, IE11-F028A, IE21-F005A, and IE21-F0318) tested under differential pressure conditions ranging from 220 to 320 psid. The licensee's evaluation revealed apparent valve factors greater than its assumed valve factor of 0.30 for Valves IEll-F028A, IE21-F005A, and IE21-F031B, based on valve port d'cmeter. The inspectors noted that the licensee used VOTES mark C10 (an e sumed flow cutoff point) instead of the VOTES mark C11 (the observed nard seat contact point) in determining apparent valve factors lower than calculated by the inspectors. The licensee's selection of a point on the force trace as representing flow cutoff was based primarily on force trace characteristics and not actual flow stoppage at that valve disk position. The licensee's selection of an apparent flow cutoff point in evaluating test data was questionable because of the difficulty in selecting the flow cutoff point directly from the force trace and the repeatability of the torque switch.
Therefore, the selection of the highest thrust required to overcome dynamic flow up to the plateau on the force trace caused by the valve disk sliding on the seating surface (identified as VOTES mark Cll) would have provided confidence that flow had been isolated.
The inspectors noted that the test data for certain of the sampled MOVs ,
revealed load sensitive behavior where the thrust delivered by the motor l actuator at torque switch trip was lower under dynamic conditions than !
static conditions. In response to this finding by the inspectors, the licensee determined that the thrust delivered at torque switch trip for Valves IEll-F005A and IE11-F028A under dynamic conditions was approximately 15 and 5 percent lower than the thrust at torque switch trip under static conditions, respectively. The test data also indicated that Valve IE11-F028B delivered approximately 15 percent less thrust at torque switch trip under dynamic conditions than static conditions. The licensee determined that the thrust at torque switch trip for Valys 1E11-F015A was approximately 10 percent higher under i dynamic conditions than under static conditions. The sampled Hatch test l data indicate that load sensitive behavior can exceed the margin
'
included by the licensee in its HOV calculations for torque switch repeatability.
Procedure 50AC-MNT-008-0S in Sw ;on 8.5.1 requires identification of abnormalities in test data (including inadequate sizing) but specifically excludes data obtained from initial baseline testing. The NRC regulations in Appendix B to 10 CFR Part 50 require licensees to evaluate test information from safety-related equipment to ensure that the equipment continues to be capable of performing its safety function.
This requirement of the NRC regulations was emphasized in response to Question 44 in Supplement I to GL 89-10. Section 8.5.1 of Procedure 50AC-MNT-008-0S does not appear to be consistent with this because it allows baseline test data not to be evaluated at Hatc . _-__. _ - _ --- .
-. . _ _ _ _ _ _ _ - _ -._ ___ _
-
.
'
.
'
The NRC staff in"ntified the concerns regarding the evaluation of MOV test data during the inspection of the development of the GL 89-10 program at Hatch in 1992. The failure to evaluate MOV dynamic test data to determine design-basis operability before returning the M0V to i
'
service and to verify the design-basis assumptions in sizing and setting safety-related MOVs constitute a violation of Criterion XI, " Test Control," of Appendix B to 10 CFR Part 50 (identified as Violation 50-321,366/93-14-01, Failure to Evaluate MOV Test Data in a Timely Manner).
The licensee should evaluate its test data and determine whether concerns exist regarding the capability of MOVs that have not been tested under design-basis conditions. The licensee will also need to address the provisions for independent review of test data. Such a review will need to include consideration of uncertainties in the test i
'
data, such as torque switch repeatability as specified in Limitorque Maintenant.e Update 92-02. Further, the licensee will need to reconcile the test results with its design-basis assumptions for valve factor, stem friction coefficient, load sensitive behavior, stem lubrication degradation, and packing load. The inspectors will review the licensee's efforts during a future inspectio In reviewing the test packages for Valves IE11-F028A and B, the inspectors found that the test data revealed a potential operability
'
problem with Valve IEll-F028A that the licensee did not recognize, correct, or report (as appropriate) in a timely manner. In March 1990, the licensee tested Valve IEll-F028B under dynamic conditions which i indicated that the thrust required to operate the valve was greater than predicted by the licensee's valve factor assumption. The licensee did ;
not evaluate the test data to determine whether an operability problem '
existed with Valve IE11-F028A in light of the results from testing Valve !
IE11-F028B. In October 1991, the licensee raised the torque switch l setting for closing Valve IE11-F028A from a setting of 2 to 3 before 1 performing a dynamic test of the valve but again did not evaluate the l dynamic test dat The inspectors found that the October 1991 test data indicated that Valve IEll-F028A might not have been capable of performing its safety function at the previous torque switch setting of 2. As a result of failing to evaluate dynamic test data, the licensee did not recognize (a) in March 1990 that the test data from Valve IEll-F028B revealed a potential problem with the operability of Valve IE11-F028A, and (b) in October 1991 that the test of Valve 1 Ell-F028A indicated that this MOV might have been inoperable up to the time when its torque switch setting was increased in October 1991. Further, at the time of the inspection, the licensee had not evaluated any applicable technical specification and reportability requirements resulting from the potential problem with the operability of Valve IEll-F028A, and had not taken action required by the NRC regulations, as appropriat _ __
'
,
The failure to identify the potential problem with the operability of Valve IEll-F028A and to take corrective action to resolve the problem, is a violation of Criterion XVI, " Corrective Action," of Appendix B to 10 CFR Part 50 (identified as Violation 50-321,366/93-14-02, Failure to Identify and to Take Action to Correct a Potential M0V Operability Problem) .
The inspectors found that the licensee personnel were knowledgeable and highly skilled in the proper use of the diagnostic softwar Licensee personnel are also involved to_ a significant degree in the industry efforts to improve MOV performance. The inspectors considered the knowledge and skill of the licensee personnel to be a strengt .4 Periodic Verification of MOV Capability Recommended action "d" of the generic letter requests the preparation or revision of procedures to ensure that adequate MOV switch settings are determined and maintained throughout the life of the plant. Section "j" of the generic letter recommends surveillance to confirm the adequacy of ,
the settings. The interval of the surveillance is to be based on the safety importance of the MOV as well as its maintenance and performance history but is recommended not to exceed five years or three refueling outage Further, GL 89-10 recommended that the capability of the MOV be verified if the M0V is replaced, modified, or overhauled to an extent that the existing test results are not representative of the M0 During the GL 89-10 Part 1 program inspection, the inspectors found that the Hatch Generic Letter 89-10 MOV Program Description (dated February 19,1992) specified that periodic surveillance testing would be performed each five years or three refueling outages for all active safety-related valves listed in Procedure 50AC-MNT-008-05. In this inspection, the inspectors reviewed the revised GL 89-10 Program Document (dated December 1992) and Procedure 50AC-MNT-008-0S (Revision 2) to ascertain the licensee's periodic verification program. The program document specifies that periodic verification static baseline testing will be performed each five years or three refueling outages for active safety-related MOVs. The licensee will need to justify its method of periodically verifying the design-basis capability of its GL 89-10 MOVs. The staff will review the licensee's justification during a future inspectio Procedure 50AC-MNT-008-0S (Revision 2) in Attachment 3 contains a list of tests to be performed following certain types of maintenance activitie For valve packing adjustments, the specified test is to monitor motor running current or power. A static thrust measurement may be required if a low margin condition exists. The licensee will be expected to justify its method of determining sufficient margin to allow thrust verification to be omitted from post-maintenance testing following valve packing adjustments. During a future inspection, the staff will review the licensee's justification for determining sufficient margin to allow omission of thrust verificatio _ _.__ _ _
_ _____ _ __ ___ _ _ - _
-
.
.
. 10 MOV Failures. Corrective Actions. and Trendina Recommended actic,n "h" of the generic letter requests that licensees analyze and justify each MOV failure and corrective action. The documentation should include the results and history of each as-found deteriorated condition, malfunction, test, inspection, analysis, repair, or alteration. All documentation should be retained and reported in accordance with plant requirements. It is also suggested that the j material be periodically examined (every two years or after each refueling outage after program implementation) as part of the monitoring and feedback effort to establish trends of MOV operability.
l As discussed above, the inspectors identified a concern regarding the lack of corrective action in response to information that Valve IE11- l F028A might not be capable of performing its design-basis function. The inspectors also reviewed the licensee's corrective actions in response to performance problems with Valve 2E51-F045 and considered the licensee's actions to be appropriat The licensee's trending of MOV test parameters, maintenance problems, and M0V failures continues to be informal. The licensee formally relies on the industry's NPRDS database, which was discussed in Supplement I to GL 89-10 as not fully sufficient because of its focus on MOV failure data. The inspectors considered the licensee, as yet, not to have satisfied its commitmei.t to GL 89-10 fully in the area of trending. The staff will review the lic a ee's trending activities during a future !
inspectio In the GL 89-10, Part I program inspection report, the inspectors documented the licensee's intent to review the effect of high ambient ;
temperature on motor torque when the Limitorque study of temperature i effect on motor output was available. During this inspection, the i inspectors reviewed the licensee's response to the Limitorque 10 CFR Part 21 letter dated May 13, 1993, concerning the effect of ambient l temperature on the starting torque of ac motors. The Part 21 notice was l tracked by the site NSAC organization as Log No. 93-17 and Action Item ,
l No. AI-RC 9300198. The licensee had performed a preliminary evaluation '
. of the impact of the Part 21 notice within the scope of Supplement 3 to GL 89-10 (i.e., several MOVs used for containment isolation in high energy lines) in response to the Part 21 notice. Based on this review, ;
the licensee had not identified any MOVs in Unit 1 or Unit 2 that needed to be modified because of an unacceptable decrease in the previously calculated motor capability margin. The licensee's further response to the Part 21 notice has been delayed waiting for a supplement to the notice indicated by Limitorque to be in preparation. The inspectors indicated that the licensee is responsible for addressing any safety ,
concerns raised by the Part 21 notice in a timely manner. The i licensee's response to the Limitorque Part 21 notice on ac motor ambient temperature effects has been assigned as IFI 50-321, 366/93-14-03, Response to Limitorque Part 21 Notice on AC Motor Ambient Temperature Effect , _ _ . _ _. , ,
.
. .
- . .
~
.
l i
The inspectors did not identify any concerns regarding MOV maintenance activities.
l '2.6 Schedule l l
'
In GL 89-10, the NRC staff requested that licensees complete all design-basis reviews, analyses, verifications, tests, and inspections that were t initiated in order to satisfy the generic letter recommendations by
! June 28, 1994, or three refueling outages after December 28, 1989, j whichever is later.
l l The licensee's commitment to GL 89-10 requires that all MOVs within the
!
scope of its GL 89-10 program be tested with their design-basis l capability verified by June 1994. The licensee's schedule indicated
! that this commitment will be met. Approximately 10 dynamic tests remain l for Unit I and approximately 51 dynamic tests remain for Unit 2.
j However, the licensee plans to reduce static and dynamic testing by
- removing System 2E32, " Main Steam Isolation Valve Leakage Control
!
System," from the Technical Specifications. If System 2E32 is removed, then approximately 34 static and 35 dynamic test would remain for Unit If a schedule extension is required, the licensee should review the information-provided in Supplement 6 to GL 89-10 when it is issued. One aspect of the justification for a schedule extension is that setup of non-dynamically tested MOVs must be based on the use of best available data. Considering the current dynamic test data from Hatch and other sources, the staff does not consider a 0.30 valve factor to be the best available data for gate valves at Hatc .7 Pressure Lockina and Thermal Bindina I l
The Office for Analysis and Evaluation of Operational Data (AE0D) has completed a study of pressure locking and thermal binding of gate valves. AE0D concluded in its report that licensees have not taken sufficient action to provide assurance that pressure locking and thermal binding will not prevent a gate valve from performing its safety function. The NRC regulations require that licensees design safety-related systems to provide assurance that those . systems can perform their safety function In GL 89-10, the staff requested licensees to i review the design basis of their safety-related MOV The licensee provided documentation of its evaluation of the potential for pressure locking and thermal binding of gate valves performed in 1992. The. inspectors identified concerns about the extent that the licensee had addressed the potential for pressure locking at Hatch. For example, the licensee's justification in some cares that pressure locking would not occur was based on the assumption that the time when the MOV would be operated and the distance from the heat source was sufficient to preclude a locking condition. Further, the licensee reviewed 12 valves for pressure locking as a result of pressure transients, but focused only on maintenance work orders. This issue has
. .
. - - -
._ _ _ . . . - . _ . _ .. . _ _ _ - -. _ - _ - _ _ _ . __ - __ _
.
'
.
not been completely reviewed and is assigned as IFI 50-321,366/93-14-04, Consideration of Pressure Locking and Thermal Binding of Gate Valve .8 Followup of Concerns' Enumerated in the Part 1 Report-The inspectors reviewed the concerns raised in the inspection of the development of the GL 89-10 program at Hatch using Part 1 of TI 2515/109. Of the 18 concerns listed in the Part 1 inspection report, the inspectors noted that the licensee had made sufficient progress to close only five of the concerns. The inspectors found that the licensee had adequately addressed in the GL 89-10 Program Description (December ,
1992) the concerns (numbers 1, 2, and 3 in the GL 89-10 Part 1 inspection report) involving design-basis reviews; the concern (number 9) involving torque switch repeatability and diagnostic equipment inaccuracy assumed in MOV calculations; and the concern (number 10) involving consideration of maximum torque rating in the weak .
link analysis. Many of the remaining concerns involve MOV testing ind !
evaluation of test dat Two violations were identified and two Inspector Followup Items i assigne . EXIT INTERVIEW The. inspection scope and findings were summarized on July 30, 1993, with those persons indicated in paragraph 1. The inspectors described the areas inspected and discussed in detail the inspection result Proprietary information is not contained in this report. No dissenting comments were received from the license Item Number Description and Reference ,
,
50-321,366/93-14-01 Violation - Failure to Evaluate MOV Test Data in a Timely Manner 50-321, 366/93-14-02 Violation - Failure to Identify and to i Take Action to Correct a Potential MOV
'
Operability Problem ,
50-321,306/93-14-03 IFI - Response to Limitorque Part 21 Notice on AC Motor Ambient Temperature Effects 50-321,366/93-14-04 IFI - Consideration of Pressure Locking I and Thermal Binding of Gate Valves i
!
. _ . . . _ , _ - , . - _ _
._.- _ . . - .
. - _ _ _ _ _ - -
- . . . . _ - - . _ _ _ - - _
i
.
-
.
l 1 l 13 .
'
l
' ACRONYMS AND INITIALISMS i I
'
AE0D - Office for Analysis & Evaluation of Operational Data Boiling Water Reactor Owners Group
'
BWROG -
CST -
Control. Switch Trip ,
' Document Control Center
'
DCC -
EDSFI - Electrical Distribution System Functional Inspection .
FSAR - Final Safety Analysis Report l l GE -
General Electric ,
l GL -
Generic Letter .
HELB -
High Energy Line Break l IFI -
Inspector Followup . Item INEL - Idaho National Engineering Laboratory MOV -
Motor Operated Valve ,
'N Number l NPRDS - Nuclear Plant Reliability Data System i NRC -
Nuclear Regulatory Commission j
.NRR -
Nuclear Reactor Regulation NSAC -
Nuclear Safety and Compliance RCIC - Reactor Core Isolation Cooling 1 1 RHR -
Residual Heat Removal System i j SAER -
Safety Assessment Engineering Review
!
SCS -
Southern Company Services j SNC -
Southern Nuclear Operating Company i TI -
Temporary Instruction i TOL -
Thermal Overload <
l- VAC -
Volts Alternating Current i
V0TES - Valve Operation Test and Evaluation System i
- . . - . . . _ . - ..- -. . ., -