ML20149D283
| ML20149D283 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 09/15/1993 |
| From: | Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NYN-93127, NUDOCS 9309200095 | |
| Download: ML20149D283 (9) | |
Text
W Seab ok, NH 03874
= Telephone (603)474-9521 h [C Facsimile (603)474-2987 Energy Service Corporation Ted C. Feigenbaum i Senior Vice President and Chief Nuclear Officer NYN-93127 September 15, 1993 United States Nuclear . Regulatory Commission
- Washington, D.C. 20555 Attention: Document Control Desk
References:
(a) Facility Operating License No. NPF-86, Docket No. 50-443 (b) USNRC Letter dated August 16,1993, " Inspection Report No. 50-443/93-80," !
M. W. Hodges to T. C. Feigenbaum ;
(c) North Atlantic Letter NYN-93097 dated June 30,1993, " Revised Response to Generic Letter 91-06 (TAC M81494)," T.C. Feigenbaum to USNRC (d) North Atlantic Letter NYN-93086 dated June 16,1993, " Licensee Event Report -
(LER) 93-08-00: Control Air Not Analyzed to Function During Seismic Event,"
T.C. Feigenbaum to USNRC (e) North Atlantic Letter NYN-93107 dated July 30,1993, " Licensee Event Report (LER) 93-08-01: Control Air Not Analyzed to Function During Seismic Event,"
T.C. Feigenbaum to USNRC
Subject:
Reply to a Notice of Violation Gentlemen: !
w In accordance with the requirements of the Notice of Violation contained in Reference (b), the North Atlantic Energy Service Corporation (North Atlantic) response to the cited violations is provided as Enclosure 1.
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Should you have any questions concerning this response, please contact Mr. James M. Peschel, Regulatory Compliance Manager, at (603) 474-9521, extension 3772.
Very truly yours, ;
Ted C. Fei - aum .
TCF:JES/jes !
Enclosure 170C6S l 6
a member of the Northeast Utilities system l 9309200095 930915 PDR D*# '
G ADOCK 05000443 PDR hh
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E United States Nuclear Regulatory Commission September 15,.1993 Attention: Document Control Desk Page two cc: Mr. Thomas T. Martin Regional Administrator U.S. Nuclear Regulatory Commission 1 Region I i 475 Allendale Road l King of Prussia. PA 19406 Mr. Albert W. De Agazio, Sr. Project Manager Project Directorate I-4
. Division of Reactor Projects U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. Noel Dudley NRC Senior Resident inspector P.O. Box 1149 Seabrook, NH 03874 i
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. North Atlantic '
- September 15, 1993 f
ENCLOSURE 1 TO NYN-93127
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, , t REPLY TO A NOTICE OF VIOLATION In a letter dated August 16,1993 [ Reference (b)], the NRC transmitted to North Atlantic Energy Service i Corporation (North Atlantic) a Notice of Violation for two violations identified during the April 26 to ',
, May 21,1993 Electrical Distribution System Functional Inspection (EDSFI). The first violation was for deleting a loss-of-charger output current computer alarm without performing a written safety evaluation >
pursuant to 10 CFR 50.59. The second violation was for failing to recognize that a continuous supply ,
of control air was necessary to support operation of the emergency diesel generators. In accordance with 3
the instructions provided in the Notice of Violation, the North Atlantic response to these violations is provided below. ;
I. Violations '
Violation 1 (93-80-10): Part 50 of Title 10 of the Code of Federal Regulations, Section 50.59(b)(1) requires that the licensee shall maintain records of changes in the facility and of changes in procedures i made pursuant to this section, to the extent that these changes constitute changes in the facility as !
described in the safety analysis report or to the extent that they constitute changes in procedures as {
described in the safety analysis report. These records must include a written safety evaluation which provides the bases for the determination that the change, test, or experiment does not involve an unreviewed safety questien.
Section 8.3.2.1.f(Z of the Seabrook Updated Final Safety Analysis Report states that, " .a loss-of-current relay (Device N 37/62) is provided which senses loss-of-charger output current. This relay provides ,
an alarm locaPy at the charger and a computer alarm.' i Contrary to die above, no written safety evaluation was performed for a change to the plant as described 3 _ in the FSAlt in that, in March 1991, the loss-of-charger output current computer alarm described above
- was deleted with no written safety evaluation.
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I Violation 2 (93-80-07): Part 50 of Title 10 of the Code of Federal Regulations, Appendix B, Criterion 111, Design Control, requires that design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified ;
calculational methods, or by the performance of a suitable testing program. ;
Contrary to the above, prior to initial licensing on March 15, 1990, the plant design review failed to provide a verification that the design of the emergency diesel generator system was adequate in that the control air system was not seismically qualified, and therefore, the unexpected failure of the diesel engine i could occur when the diesel engine cooling control valves go to the as-designed full open, position upon the loss of the control air supply. This could result in excess cooling of the diesel engine and subsequent I engine failure.
- 11. Response to the Violations VIOL.ATION 1 l A. Reason for the Violation North Atlantic does not contest any portion of this violation. The reason for this violation is described below.
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~l Backcround l In March 1991, four main plant computer digital inputs from the battery charger loss-of-charger output ;
current relays (i.e., the " Battery Charger Charging Amps Low" alarms) were deleted and the computer j points were redirected to a logger function only. This was performed by Work Request 91W001726, and in accordance with Station procedure PN 1851, Revision 01, " Main Plant Computer System Computer !
Input / Output List Revision." This procedure specifically allowed changes to be made to the priority and destination of computer points with only Operations Department review, and without the completion of r a 10 CFR 50.59 applicability review. Section 8.3.2.1.f of the Updated Final Safety Analysis Report I (UFSAR) and the North Atlantic response to Generic Letter 91-06, " Resolution of Generic Issue A-30, !
Adequacy of Safety-Related DC Power Supplies," both state that the loss of DC output current from the l battery chargers will result in computer alarms.
l Root Cause i i
A 10 CFR 50.59 applicability review was not performed for the deletion of the four Video Alarm System !
(VAS) " Battery Charger Charging Amps Low" alarms due to inadequate procedural controls. Controls l were not in place to ensure that the deletion of VAS alarms identified in the UFSAR were processed in l accordance with applicable station programs, and evaluated for applicability pursuant to 10 CFR 50.59.
B. Corrective Actions That Have Been Taken and the Results Achieved j Corrective actions that have been taken for this occurrence are listed below. Please note that the specific - l 1
corrective actions stated in Inspection Report 93-80 were based on a draft Station Information Report j (SIR) evaluation that subsequently changed slightly in the final version to more fully address the stated j condition.
- 1. North Atlantic initiated and completed a Station Information Report (SIR) to evaluate this -l condition and develop corrective actions.
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- 2. North Atlantic prepared a revision to UFSAR Section 8.3.2.1.f to correctly reflect the status of j the Battery Charger current alarms. The revision to the UFSAR and the associated safety evaluation have been reviewed by the Station Operation Review Committee (SORC). j
- 3. North Atlantic performed an evaluation that compared licensing commitments pertaining to.VAS f alarms to the present plant configuration to identify any discrepancies. Licensing commitments l that were reviewed included those stated in the UFSAR, SER and its supplements, and the l Technical Specifications. This evaluation identified a number of alarm related commitments that do not agree with plant design. However, no disagreements were found between the Technical Specifications and the plant design. With the exception of one item pertaining to the lack of !
alarms for heat tracing, none of the identified items had the potential to be safety significant. i North Atlantic initiated a Minor Modification (MMOD) to revise the UFSAR and Input / Output List to address the aforementioned minor discrepancies. This MMOD is discussed further in the actions to be taken stated below.
With regard to a lack of alarms for heat tracing, a review was performed of the safety related piping lines that are heat traced and located in unheated areas. The Emergency Feedwater (EFW) supply lines were identified to have the potential to freeze in extreme cold weather if an undetected failure of the heat tracing had occurred. North Atlantic initiated an SIR to fully evaluate and develop corrective actions to address this condition. Additionally, on September 9,
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l 1993, North Atlantic made a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> non-emergency report pursuant to 10 CFR 50.72(b)(2)(iii)(B) for this condition since it was determined that it could have prevented the fulfillment of the safety i
function of a system that is needed to remove residual heat. This SIR is discussed further in the actions to be taken stated below. l
- 4. North Atlantic performed a 10 CFR 50.59 applicability review for changes to VAS alarms pertaining to priority and destination that occurred since the receipt of the Zero Power Operating License. This review excluded those alarms associated with licensing commitments that were identified as a result of Action 3, above. This review identified 13 D points that were changed from alarms to logic or logger only. The applicable UFSAR sections were reviewed and it was i determined that these alarms and the indications they provide were not described in the UFSAR.
Notwithstanding this, North Atlantic prepared a safety evaluation and concluded that an unreviewed safety question did not exist. 1
- 5. Station procedure PN 1851, " Main Plant Computer System Computer InpuuOutput List Revision," was revised to ensure that priority and destination changes to VAS alarms are reviewed against station design and the UFSAR.
- 6. North Atlantic updated the response to Generic Letter 91-06, " Resolution of Generic Issue A-30, l Adequacy of Safety-Related DC Power Supplies," on June 30, 1993, via NYN-93097 (
[ Reference (c)]. This updated response revised the reference to the alarm that had been deleted. '
D. Corrective Actions That Will Be Taken to Prevent Recurrence i The following corrective actions will be taken:
- 1. Nonh Atlantic initiated an MMOD to revise the UFSAR and Input / Output List to address minor discrepancies identified during the aforementioned evaluation that compared licensing commitments pertaining to VAS alarms to the present plant configuration. This MMOD and its associated safety evaluation have been approved by the SORC, and it is anticipated that it will be fully implemented by October 1,1993.
- 2. As stated above, North Atlantic initiated an SIR to evaluate the lack of heat tracing alarms. It is anticipated that this SIR evaluation will be completed by October 15, 1993. ;
i E. Date When Full Comoliance Will Be Achieved Nonh Atlantic is currently in full compliance with all regulatory requirements cited in this Notice of ,
Violation. This compliance was achieved when a UFSAR change and its associated safety evaluation !
pursuant to 10 CFR 50.59 were performed for the battery charger alarms that were previously deleted. j 3
VIOLATION 2 ]
A. Reason for the Violation l l
1 North Atlantic does not contest any portion of this violation. The reason for this violation is described l below. l I3ackcround
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l As stated in References (d) and (e), North Atlantic identified a condition that is contrary to the design !
description stated in the UFSAR. Speci6cally, it has been identified that failure of the air supply to the j Emergency Diesel Generators (EDG) jacket cooling water temperature control valves during a seismic event could cause overcooling of the EDGs, which potentially could preclude long term operation of the engines. This is contrary to the UFSAR, which states that the functional performance _of the cooling ,
water system is not adversely affected by environmental occurrences, abnormal operation, accident conditions and loss of power. This UFSAR statement was based on the response to NRC Request for l Additional Information (RAI) 430.111 which was incorporated in FS AR Amendment 48 (January 1983). '!
I Contrary to the above, the EDG manufacturer (Colt Industries) has determined that with the control !
valves in their maximum cooling positions, the relatively rapid cooling of the jacket water could cause engine damage to the cylinder liner / jacket, piston scuff' m g or piston seizure due to non-uniform j component thermal expansion.
Each EDG is equipped with an independent starting and control air system. The starting air system ,
consists of an air start compressor, air receivers and associated piping. The EDG air start compressors f are relied upon to re-charge the air receivers to provide the required starting air and suf6cient control !
air for long term operation. The air-start compressors are highly reliable units. However, they are not -
currently described in the UFSAR as being qualiGed to withstand a design basis seismic event and they l' are powered from seismic Motor Control Centers (MCCs) which supply non-nuclear safety loads. The event most likely to cause both EDG air start compressors to simultaneously malfunction is a design basis seismic event. The design basis assumes that all non-safety loads fail during the design basis seismic event which could potentially cause the feeder breakers to the MCCs to trip open. Upon further !
investigation it was determined that only the feeder breaker to MCC 511 would trip open and power ,
, would remain uninterrupted to MCC 611. If the design basis seismic event were to adversely affect the j air start compressors or their MCCs, the receivers would slowly bleed down over a period of 7-15 hours ;
resulting in the jacket cooling water system temperature control valves going to their maximum cooling i position.
Root Cause The primary root cause of this event was a lack of understanding the significance of control air availability for long term EDG operation. During the initial design phase both the vendor (Coltec) and '
United Engineers and Constructors (UE&C) did not identify that the air compressors were critical to EDG l operation. The primary design focus for the starting air system was assuring that enough air volume was j present in the air receivers to ensure Eve 10 second starts of the EDG per Branch Technical Position l 3 Requirements. Long term availability of control air apparently was not considered by either Coltec or l UE&C during the design phase.
A lack of understanding by YNSD/PSNH/Coltec of the significance of control air for extended EDG operation has been demonstrated. In September 1982 a potential Robertshaw temperature u ?.rol valve 4
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failure mechanism was reported pursuant to 10CFR50.55(e)(3). The failure mechanism that was reported )
- could result in the valve controlling at a lower temperature resulting in EDG overcooling. The letter j acknowledges that the EDG jacket water heat exchangers were designed to providejacket cooling water j at 110 F with 90 F Service Water based on rated load operation. The letter further states "... at reduced i load, and with colder Service Water, a control valve malfunction could cause overcooling in the engine, j and a possible engine failure could constitute a substantial safety hazard." Contrary to this, FSAR !
Amendment 48 was issued five months later indicating that a loss of control air "will not result in an l engine shutdown or degradation of engine performance." The impact of a loss of control air pressure !
with reduced Service Water temperatures on the operation of the EDG was not considered. ,
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B. Corrective Actions That Have Been Taken and the Results Achieved l.
Corrective actions that have been taken for this occurrence included the following: !
- 1. On May 18,1993, North Atlantic reported this event pursuant to 10 CFR 50.72fb)(1)(ii) as a condition outside the design basis of the plant.
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- 2. North Atlantic prepared a Preliminary Operability Determination for the Emergency Diesel l Generators which was supported by Engineering Evaluation Number 93-028. This evaluation {
documented the seismic functionality of the diesel air start skid, utilizing available seismic documentation and Engineering judgement. Engineering . Evaluation Number 93-028(RI) confirmed the seismic capability of ht e n start skid and concluded that through the use of available seismic documentation and operator action the EDG air start skid will function to i support the EDG during a seismic event. Subsequently, a Final Operability Determination was !
prepared which supported the conclusions reached in the preliminary determination. ,
- 3. Operations Department management initially issued a standing operating order describing the l method for restoring power to MCC 511 and MCC 611, in event that the feeder breakers to the ,
i MCCs should trip during a seismic event. This guidance was subsequently incorporated into EDG local alarm response procedures. This provides procedural guidance for restoring power .;
to these MCCs upon receipt of the air receiver low pressure alarm. !
- 4. North Atlantic initiated and completed a Station Information Report (SIR) to evaluate this condition and develop corrective actions. ,
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- 5. On June 16, 1993, North Atlantic submitted Licensee Event Report (LER) 93-08-00 via l NYN-93086 [ Reference (d)], which documented the EDG control air issue. This LER was !
subsequently supplemented by LER 93-08-01 on July 30,1993 via NYN-93107 [ Reference (e)].
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- 6. North Atlantic developed a Minor Modification (MMOD) to revise the UFSAR and design i documents to reflect the appropriate safety classification of EDG starting air components.
- 7. Installed EDG equipment has been upgraded via commercial grade dedication reflecting revised j design documents. This ensures that only items of the proper safety classification are issued for :
use in the EDG control air system.
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D. Corrective Actions That Will Be Taken to Prevent Recurrence To ensure long term operational availability of the EDG control air system the following corrective ;
actions will be taken: l
- 1. Programs and procedures will be updated to ensure long term operability of the EDG.
IST Programs and Procedures Maintenance Programs and Procedures It is anticipated that these updates will be completed by April 30,1994. I
- 2. A program will be developed to trend air consumption of the EDG air system.- The air consumption data will be utilized in the development of a Technical Clarification which will address the impact of air system preventative maintenance on EDG operability. It is anticipated ,
that this Technical Clarification will be developed by November 15, 1993. !
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- 3. An evaluation will be performed addressing EDG reliability as a result of reclassification of l control air components, it is anticipated that this evaluation will be completed by November 15, ;
1993. Potential enhancements if required are anticipated to be proposed by May 30,-1994.
- 4. A design basis document will be developed for the EDGs, including the safety classification of :
support systems. It is anticipated that this will be completed by December 31,1994. j E. Date When Full Compliance Will Be Achieved !
North Atlantic is currently in full compliance with all regulatory requirements cited in this Notice of ;
Violation. !
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