ML20077Q337
| ML20077Q337 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 08/14/1991 |
| From: | Joshua Wilson TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9108210196 | |
| Download: ML20077Q337 (11) | |
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August 14, 1991 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR PLANT (SQN) - NRC INSPECTION REPORT NOS. 50-327, 328/91 RESPONSE TO NOTICE OF VIOLATIONS 50-327, 328/91-08-01, 03, AND 05 contains TVA's response to B. A. Wilson's lettet to D. A. Nauman dated July 1, l991, which transmitted the subject notice of violations dealing with f:! Lure to correct tae flooding of handholes and manholes for lE cables, failure to follow procedures associated with fire protection testing, and inadequate design evaluation of main steam check valve modifications. A summary of the new commitments contained in this submittal is provided in Enclosure 2.
A two-week extension for this response was tequested and approved by Mr. J. Brady of your staff in a telephone conversation heli August 1, 199t.
If you have any questions concerning this submittal, please telephone M. A. Cooper at (615) S43-8422.
Very truly yours, TENNESSEE VALLEY AUTHORITY
,.S (A L. Wilson j
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See page 2 Shi f4 9108210196 910814
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2 U.S. Nuclear Regulatory Commission August 14, 1991 cc (Enclosures):
Mr. D. E. LaBarge, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20S52 NRC Resident inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy Tennessee 37379 Mr. B. A. Wilson, Project Chief U.S. Nuclear Regulatory Commission Region Il 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
, ENCLOSURE 1
' RESPONSE TO NRC INSPECTION. REPORT NOS.' 50-3*J7/91-08 A"D 50-3?8/91-08 B. A. WILSON'S LETTEJ 0 D. A. NAUMAN j
DATED JULY i, 1991
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1 Violation'50-327.-328/91-08-03 "A.- Technical Specification 6.8.1 requires that procedures recommended in Appendix A of Regulatory Guide 1.33, Revision-2, be established, implemented and maintained.
This includes maintenance, operating, surveillance, administrative, and fuel handling procedures. The-requirements of TS 6.S.I.are implemented in part by the following procedures:
"1.
Site Standard Practice 8.1, Section'2.1 delineates the' qualification requirements for-test directors. -Section 2.1.B requires that-responsible supervisors shall make'sure that perstnnel assigned as Test Directors.have thorough knowledge and adequate abilities to
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. perform'and/or direct a test.
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" Contrary to the-above -responsible supervisors'did not assure that two Fire Protection Unit personnel who were assigned as. Test Directors.for Surveillance Instruction 0-SI-SFT-026.002.0, Auxiliary Building Fire Protection System Hydraulic _ Performance Verification, which was accomplished-on April 2,:1991 were properly qualified as
, required by the standard practice.
"2.
SI-1, Surveillance' Program, section'9.2.3.17, requires that,'for all
-TS SI's.Lall other reviews, as specified on the1 routing sheet (Attachment 7),Lmust be completed and the package hand-delivered to
- the-Periodic Test Section within 10 calendar days of the test-l completion.
" Contrary to the above, the review cy:le for.SI 0-SI-SFT-025.002.0,
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-Auxiliary Building System Hydraulic Performance Verification, perfor.ued on April 2,- 199'.. took a total of131 davs to camplete "This is-a Severity Level IV violation (Supplement I)."
T Adinission or Denial 1of the Alleged ' Violation
--TVA admits the viola-ion.
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Reason'for the Violation The-cause_ of fnot_ ensuring that assigned test directors were properly qualified was lack of communication of expectations and' responsibilities between the Fire Protection Unit (FPU) management and FPU forem,'.
This was a direct result of the reorganization in 1989, which reassigned direct supervisory management over.the FPU from the Fire Protection manager to the Operations Support supervisor, Direct supervisory nanagement over the FPU was not effectively assumed following the reorganization.
The poorly supervised FPU i
foremen ~did_not assume the_ responsibilities and management control over the i
test director qualification process.
Before the reorganization, the FPU
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= manager had_made the test director assignment based on the knowledge of the training program for test directors.
In addition, qualification cards were maintained by the ;FPU manager for surveillance _ instructions (sis) f or which o
they had responsibility.: The FPU foreman involved did not ensure that the individual assigned as test' director for the performance of 1
SJ SI-SFT-026.002.0, " Auxiliary Building Fire Protection System Hydraulic Performance Verification," was qualified and trained on this test as required by-Site Standard Practice (SSP) 8.1, " Conduct of Testing." The toreman was not knowledgeable of these requirements and had not been given clear supervisoryfdirection, j
The delay in reviewing 0-SI-SFT-026-002.0 resulted from the FPU foreman i
re'sponsible for-the review rotated-offshift for seven days before forwarding j
the completed SI to the Technical Sspport group. Campeting priorities in the Technical Support group allowed the SI to remain unreviewed for approximately three additional. weeks.
Additional details concerning this event were provided in Licensee Event
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1 Report'(LER)_ 50-327, 328/91009 dated June 5, 1991.
i Corrective Steps That Have Been Taken and Resulty Achieved As corrective action, an interim organization has been established to identify and correct system problems and provide management's overs'ight to:the FPU daily activaties.-- The_ interim-FPU supervisor has reviewed and discussed this
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event with the FPU personnel -stressing expectations and responsibilities j
regarding work practices and timeliness of technical reviews.
Additionally, l
as an interim measure, retraining of the FPU personnel on the requirements'of 1
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SSP-8.1 was perfo~rmed. -Qualification-cards, which are the validation 5
mechanism that on-the-job training has been completed, were formally I
established _to track FPU personnel training and qualification to serve as test
. directors 1for specific-tests._ Additionally, to ensure that FPU personnel are qualified-to act as test director on a given. test, Attachment
" Fire Protection Foreman 1 Duty Station Checklist," of procedure 0-PI-FPU-000-299.0,
" Operations Fire Protection Foreman Shift and Status Check Sheet," requires 1
specific checkoffl that the appropriate training and qualifications have been
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. A detailed ounseling session with the interim FPU supervisor, the FPU foreman, test director, and Plant Manager was conducted, which reinforced the responsibilities of each individual with respect to performance of a test and their role in review of test packages.
The SQN Plant Manager has recently restructured and refocused the daily plan-of-the-day meeting with significant emphasis on SI performance.
This i
includes both timely surveillance performance and review cycle completion.
Srbstantial improvement in timeliness of SI review performance has been observed to date.
Corrective Steps That Will Be Taken to Avoid Further Violations It was concluded that additional training was needed to t.sure proper understanding of requirements for conduct of testinc.
Given the importance of this function and to further ensure that test directors clearly understand their responsibilities and mar,agement's expectations, test directors will be retrained, and the selection and qualification of test dire ( tors will be controlled by a senior plant manager.
This is intended to ensure that an adequate level of experience for each individual evolution is maintained during the performance and during review of test results to obtain a thorough and accurate finished product for plant sis.
This training will be complete by October 1, 1991.
Broader improvements in overall conduct of the fire protection program have been initiated. A fire protection program improvement task force is addressing such areas as organization and responsibilities, training, procedures, trending analysis, and hardware condition. These efforts had been initiated prior to this event, but had not progressed sufficiently to prevent this occurrence.
The broad-based nature of these activities is serving to heighten priority and awareness toward activities affecting the fire protection system.
The interim FPU organization has been established under the efforts of the program improvement task force. The schedule for implementation of the improvement plan is being developed to prioritize and accomplish broad-based improvement efforts.
The interim organization will remain in place until sufficient progress is made in the completion of the improvement plan effort <.
At that time, TVA will establish a permanent organization appropriate for continued long-term implementation.
Date When Full Compliance Will Be Achieved Sequoyah is in full compliance.
Ongoing fire protection program improvement erforts are expected to result in identification of additional areas for Improvements, which, as addressed, should result in further long-term impros
.nts in overall program implementation and performance.
Violation 50-327, 328/91-08-01 "B.
10 CFR 50 Appendix B Criterion XVI states that measurer shall be established to assure that conditions adverse to quality, such as failures, malfunction, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected.
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" Contrary to-the above, froml1989 until May 1991, the licensee did not correct
- a condition adycrse to quality pertaining to the flooding of manholes containing safety-related diesel generator cables in that the condition continued to occur and the licensee did not take any further action which would have corrected the problem.
"This is a Severity Level IV violation (Supplement I).
Admission or Denial of the Alleged Violation TVA admits the violation.
- Reason for the Violation Corrective actions for preventing recurrence of flooding of manholes and-handholes (MH/HHs) were not aggressively or ef f ectively pursued to prevent
. recurrence. Short-term corrective actions, which were taken prior to restart of the SQN units in 1988 for MH/HHs, included repair of broken condulets, filling cracks, megger and high potential voltage testing as appropriate, i
cleaning of MH/HHs, and performance of evaluations indicating that the cables were functioning properly and fit for. duty. The proposed long-term corrective L
actions were revised without full documentation to support the technical bas!s
' for the revised plan or to properly track completion within established programs. The revised approach to address flooding in the long term included
- performance of_ preventive maintenance (PM) inspections on an annual basis with the results to be reported to Nuclear Engineering (NE) for evaluation.
Following additional review, it has been concluded that these long-term actions would have been inadequate to prevent recurrence of flooding of the MH/HHr, and that, as defined, the actions had not been properly implemented.
The long-term corrective action to perform annual PMs was inadequate to fully ade.ess the flooding in MH/ hlb since issues such as the operation of sump puups-and changes in the drainage and grading of the plant were not taken into account. Additionally, the PMs were not fully performed as scheduled, and the-results were not consistently transmitted to WE for evaluation. While several factors contributed to this situation..it is concluded that because of the perceived low safety significance of the issu', insufficient focus and i
priority were ap3 iled to ensure that the necessary corrective actions were-taken to provent incurrence of flooding.
The postulated failure. mechanism for the submerged cable is a phenomenon called " treeing," which is a gradual breakdown of the dielectric insulation i
material caused by impurities in che moist or wet' medium surrounding the cable.
This breakdown is age related and is precipitated when the cables are Leontinuously energized and lightly loaded.
For.the safety-related cables in.
MH/HHsLat SQN, medium voltagu, cross-linked-polyethylene (XLPE)-Jacketed cables'are the most susceptible to treeing.
The 6.9-kilovolt (kV) emergency raw cooling water (ERCW) motor-control center (MCC) supply. cable is XLPE
-jacketed and is lightly loaded and continuously energized.
Other medium s
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' i voltaga cables in the MH/HHs are the power feeds to the ERCW pump motors and the diesel' generator f eeds to the 6.9-kV shutdown boards. The pump motors are l
- moderately. loaded and thus do not fall into the category of being highly susceptible to treeing. The-diesel generator (D/G)' feeds are l
ethylene-propylene rubber insulated tha have been evaluated by the industry to not be as susceptible to treeing.
Additionally, the D/G cables are only intermittently _ loaded during periodic surveillance testing.
For the 6.9-kV supply cable in the ERCW MCC, the. safety-related devices
~ serviced by this cable consist of the strainer, screen wash pump, traveling screen, ERCW' header-isolation valve, and station deck sump pump.
The effect of a cable failure would not be it aediate, and adequate time exists to take i
manual actions upon annunciation of loss of the MCC.
In addition, an alternate source of shutdown power is available through a bus tie and breaker
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system that can be manually realigned to reenergize the lost MCC board.
-Irrespective of the safety consequences of this condition, this adverse condition was not resolved in a timely manner.
Long-term resolution of the flooding of MH/HHs resulted from an extension and cancellation policy i
previously allowed by the PM program and the failure to ensure sufficient l
anagement' oversight of the FM program.
Poor coordination of the logistics nvolved with' performing the MH/HHs inspections, deferrals of the PMs prior'to 1
L their classification as mandatory PMs. and the improper use of a PM program i
status-_ code following their_ classification as mandatory PMs that prevented the subject PMs.from appearing on the delinquent PM list were also contributing j
factors, These problems resulted in delay in performance without full management cognizance.
In addition, when the PMs were performed NE was not 1
always notified of'the results nor did they receive a copy of the completed FM performance in all cases as required.
This appears to have resulted from lack of clarity in the PM work instructions in delineating responsibility to
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forward the_ completed PMs to the responsible indi*11 dual within NE.
The annual l
frequency of the MH/HH PMs'was determined to be inadequate to establish trend data patterns _that would yield.useful information -f rom which appropriate l
corrective actions could be establisned.
In summary,_ based on the review of this issue, it is concluded that the l.
process for resolution and implementation of the corrective action program was L
not followed.
Corrective Steps That Have Been loien-and Results Achieved SQN_has performed, as an interim measure, an assessnent for the current l
condition of the affected cables and concludes that they are capable of performing their intended function. This conclusion is supported by megger and high potential testing of the cables associated'with motors with greater j
than 100-horsepower loads and an evaluation of the causes of industry f ailed l
cables to i.able conditions at SQN.
This disposition will ise f ormally documented by September 6, 1991.
In addition, the arnual MH/HH PNs are currently being performed.
Five out of the 27 MH/HHs'that were inspected to L
date contained water.
Appropriate actions have been initiated to correct the i
identified problems.
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PM procedure SSP-6.3,_" Preventive Maintenance," was effective January 22, 1991, L
.and includes the control of the deferral process of PMs.
PMs classified as l
nonmandatory now receive both Technical Support engineering and responsible L
section management review and-approval for deferrals.
PMs classified as mandatory or regulatory receive both Technical Support engineering and i
Maintenance Superintendent review and approval for deferrals. Any -f?1 tha t is delinquent and not deferred is being tracked and brought to management's attention once a week,in the plan-of-the-day meeting, posted in the." War Room,"
and discussed in the Maintenance Superintendent's weekly staff meeting.
The current PM procedure does not allow the use of an Et status classification.
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Corrective Steps That Will Be_Taken to Avoid F.urther Violations
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New PMs will be written to measure water level in the MH/HHs on a nonthly f
basis. The PMs will be implemented by October 4, 1991, following-
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implementation of a design change notice (DCN) to. provide a " dipstick" f or measuring the water level in_the MH/HHs by September 20, 1991.
af~er the monthly PMs are implemented, conditional performance PMs requiring
' implementation when water is identified in MH/HH by the monthly PM8 will be implemented to' provide NE. appropriate information. These conditional PMs will
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require performance of.necessary maintenance activities.
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In: addition to the modification to add dipsticks to the MH/HHs, power receptacles for_the MH/HHs containing a sump pump are being moved to the highest-possible location to prevent shorting out of the sump pwnps because of i
flooding. Tliis will be completed by January 15, 1992.
Drainage problems involving the MH/HHs are to be corrected by ensuring that grade levels are restored and/or graded in such a manner that either. runoff is routed away from l
the MH/HHs to storm drains or the MH/HHs raised above the existing grade.
Localized grading will be performed to improve drainage around MH/HHs by
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-October 4, 1991.
DCNs have been issued and will be implemented by
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October 4, 1991, for installing additional curbs and raising the MH/ uhs and j
transformer. vault walls.
In addition, configuration controls necessary for
-land management will be evaluated _by December 16, 1991.
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~ SQN is, continuing an ongoing effort to effect improvements in problem
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identification, resolution, and implementation of ccerective action program j
initiatives. This-effort includes emphasis being pieced cn achieving accurate
_rooticause determination, including full identificat mn of corrective actions i
L necessary'to correct identified problems and prevent recurrence, middle-level management ownership and accountability for problem recolution, impl3 mentation i
of programsatic solutions, and ~n institutionalized process for assessing effectivenesa of corrective actions and initiatives.
An effectiveness review of corrective actions established for MH/HH flooding i
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Date When Full Compliance Will Be Achieved
~TVA will be in full compliance by January 15, 1992, apon completion of identified corrective actions.
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. Violation 150-327, 328/91-08-05 "C. LThe' Code of Federal-Regulations, 10.CFR 50, Appendix h Criterion III,
_ Design 0ontrol requires that measures shall be established to assure that applicable regulatory _ requirements and the design basis'for those structures,_ systems, and components to which this appendix applies are-
-correctly translated into specifications, drawings, procedures, and instructions._ In addition, it states that design changes, including
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field' changes shall:be. subject to design control measures commensurate with those applied to the original design.
There' measures shall provide for verifying or' checking the adequacy of the design.
" Contrary to the above, the design control measures for the field change applied to the safety-related main steam check valves for Unit 1-in May of 1990 did not' adequately: evaluate changes to the valve.< uad did'not provide adequate instructions-for the modification resulting in failure of three' main steam check val es identified in October 1990.
"This is a Severity Level IV violation (Supplement I)."
' Admission or Denial.of the Alleged Violation TVA' admits the violation.
Reason'for the Viniation
.As described in LER 50-327/90024 dated November 7,1990, tne root cause of the
- main steam checkivalve (MSCV)- f ailures-was determined to be an inadequate E
evalkation of the method of. implementation associated with the Unit 1 Cycle 4 weld repair modification. The' actual-failure mechanism was-high cycle, low
. stress:fa:Igue of the. pest caused by reverse bending at the thread to shoulder Li interface.- Performing the weld repair of the post in the restrained condition as allowed by the design change and vendor concurrence, i.e.,-with the post attached to the disc, caused a. change in-the residuai stress at the post (shoulder:that reduced'the dynamic-loads required to initiate ani propagate p
fatigue failure. _This conclusion is consistent with the results of the
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. evaluations and reviews by Westinghouse Electric Corporation and APTECH~
Engineering Services, Inc.
The potential for this interaction was not foreseen during the design review and implementation process.- Contributing P
cfactors'to this error include, inadequate: consideration of how-implementation
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aspects--could intrcduce unanticipated interactions impacting the effectiveness of the design. _Also, an inadequate review of the vendor's basis for concurrence and ascessment of the' vendor's capability to perform the
- evaluation requested was performed.
. Corrective Steps That Have Been Taken and Results Achieved
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Actions have been taken to heighten sensitivity of NE personnel to the potential for similar. interactions'and the impact that implementation processes may have on a design-and to ensure that when relying on vendor concurrence, TVA understands the basis for that concurrence.
Sequoyah Engineering Procedure 26 " Design Change Ccntrol," was revised to ensure the vat paty of vendor information and che importance in verifying acceptability g
tor _ safety-related service.
In addition, training has been provided to-design l,
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engineers-on the utilization of vendor information in developing design output
' and that when requesting de' sign informatior. between design disciplines,: to clearly communicate the-end use of the information to better comrnnicate between disciplines.
Corrective Steps That Will Be Taken to Avoid Further Violations No additional corrective actions are required.
Date'When Full-Compliance Will Be Achieved TVA-is:in fullLeompilance.
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ENCLOSURE 2 List of Commitments 1.
TVA will issue a new series of regulatory preventive maintenance (PM) to measure water level in the manholes and handholes (MH/HHs) on a monthly basis by October 4, 1991.
2.
TVA will complete the modification to add dipsticks to the MH/HHs by September 20, 1991.
3.
Power receptacles for the MH/HHs containing a sump pump will be moved by January 15, 1992, to the highest possible location to prevent the shorting out of the sump pumps because of flooding.
4.
DCNs will be implemented by October 4, 1991, for the installation of additional curbs and raising the MH/HHs and transformer vault wells.
5.
Localized grading will be performed by October 4, 1991, to improve drainage of MH/HHs.
6.
TVA wil? perform a safecy assessment that addresses the technical implications associated with past and current MH flooding (cable damage and splices) by September 6,1991.
7.
An effectiveness review of corrective actions established for the MH/HH incident will be performed by January 15, 1992.
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Test directors will be retrained, and the selection and qualification of test directors will be controlled by a senior plant manager. This training will be completed by October 1, 1991.
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