ML20012C496

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LER 90-010-00:on 900205,discovered That Standby Shutdown Facility Wide Range RCS Temp Indications Had Not Been Subj to Monthly Channel Check as Required by Tech Spec 4.7.13.6. Caused by Defective procedure.W/900307 Ltr
ML20012C496
Person / Time
Site: Catawba Duke Energy icon.png
Issue date: 03/07/1990
From: Glover R, Owen T
DUKE POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-010, LER-90-10, NUDOCS 9003220073
Download: ML20012C496 (7)
v • d • e


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Clover 3 C ?!Ino DUKEPOWCH March 7, 1990 Document Control Lesk

-U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

Catawba Nuclear Station Docket No. 50-413 LER 413/90 Gentlemen:

Attached is Licensee Event Report 413/90-10, concerning TECHNICAL SPECIFICATION VIOLATION DUE TO MISSED MONTHLY SURVEILLANCE OF SSF REACTOR COOLANT TEMPERATURE INDICATION DUE TO DEFECTIVE PROCEDURE.

This event was considered to be of no significance with respect to the health and safety of the public.

ry truly yours, l%

Tony B. Owen Station Manager keb\LER-NRC.TBO xc: Mr. S, D. Ebneter American Nuclear Insurers Regional Administrator, Region II c/o Dottie Sherman, ANI Library U. S. Nuclear Regulator Commission The Exchange, Suite 245 101 Marietta Street, NW, Suite 2900 270 Farmington Avenue Atlanta, GA 30323 Farmington, CT 06032 M & M Nuclear Consultants Mr. K. Jabbcur 1221 Avenues of the Americas U. S. Nuclear Regulatory Commission New York, NY 10020 Office of Nuclear Reactor Regulation Washington, D. C. 20555 INPO Records Center Suite 1500 Mr. W. T. Orders 1100 Circle 75 Parkway NRC Resident Inspector Atlanta, GA 30339 Catawba Nuclear Station /Jf

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  • Technical Specification Violation Due to Missed Mc,nthly Surveillance Of SSF .

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_ y 20 406teH1Hivl 60.73taH2Hel 90.73 eH2HvillH91 l 20 4051aH1Hol 60 73:eH2Hilil 50.731aH2Hal LICE AAEE CONTACT FOR THl$ LER 1121 NAME TELEPHONE Nuv6ER 8 9E A CODE R.M. Glover, Compliance Manager 81013 813 11l-l 31i1317 COMPLETE ONE LINE ,OP E ACH COMPONENT F Al(QItt DE& Oft l$ED lN THl$ flEPOflT_1131 COMPONE N, M C REPORTA LE g g , g M C Ripos t A LE CJ.USE 8v8 TEM I I I I I I I I - i I I I I I_

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On February 5, 1990, Unit 1 was in Mode 6, Refueling, and Unit 2 was in Mode 1, Power Operation, when it was discovered, at approximately 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br />, that the Standby Shutdown Facility (SSF) wide range Reactor Coolant System (NC) temperature indications had not been subjected to a monthly CHANNEL CHECK as required by Technical Specification 4.7.13.6. This incident is attributed to a Defective Procedure. These indications were overlooked for inclusion in the monthly surveillance precedures when the original modification package (to add wide range NC temperature indication to the SSF) was reviewed for affected procedures in November 1984. Affected procedures were/will be revised. A review is being performed to ensure that all required SSi instrumentation devices are included in the monthly CHANNEL CHECKS and 18 month CHANNEL CALIBRATIONS.

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0 l0 0] 2 oF 0l6 BACKGROUND The Standby Shutdown Facility (SSF) is designed as a minimally equipped back up 4 - to the Control Room [EIIS:NA] and Auxiliary Shutdown Panels to be used in the event of a major fire, sabotage, or a total of loss of all AC power. It has enough controls to get either Unit I and/or Unit 2 to Mode 3, Hot Standby, maintain that condition for 3 1/2 days, and then to proceed to Mode 4, Hot Shutdown. The SSF is not designed to perform its functions concurrent with other design basis events; it is not nuclear safety related (except where required for interfaces with existing plant equipment) and is not desigi sd to the single failure criterion.

The SSF is designed to ensure compliance with the security requirements of 10CFR73 and to preclude radiological releases in excess of 10CFR100 limits. SSF equipment and piping is contained in vital areas of the plant and is protected from. sabotage damage; all equipment in non-vital areas is assumed to be rendered inoperable from sabotage damage. Credit can be taken, however, for Operator action.

The SSF is designed to ensure compliance with 10CFR50 Appendix R, Fire Protection Program, requirements to achieve Mode 4 conditions within 3 days by employing appropriate damage control measures to cold shutdown equipment. Fire induced spurious operation of valves [EIIS:V] or other components shall not preclude achievement of Mode 3 conditions.

The SSF provides sufficient controls and indications to achieve and maintain natural circulation in the Reactor Coolant [EIIS: AB] (NC) System. The SSF encompasses alternate and independent means to achieve and maintain Mode 3 conditions by providing primary side volume and pressure control, secondary side volume and pressure control, and the necessary instrumentation [EIIS:XI] to monitor primary, secondary, and Reactor parameters. The SSF also provides the necessary back up power (SSF Diesel Generator [EIIS: GEN]) to accomplish these functions.

Operations procedure PT/1(2)/A/4600/03A, Monthly Surveillance Items, Enclosure 13.6, SSF Monitoring Instrumentation, lists the instrumentation to be checked once per 31 days as require) by Technical Specification Section 4.7.13.6. The enclosure lists each instrament/ monitor on the SSF control panel and indicates acceptance criteria, qualifying conditions, recorded data, and applicable modes.

Technical Specification 4.7.13.6 states that "Each Standby Shutdown System instrumentation device shall be demonstrated OPERABLE by performance of a CHANNEL CHECK at least once per 31 days and a CHANNEL CALIBRATION at least once per 18 months". Specific instruments are not listed.

A CHANNEL CHECK is defined as a qualitative assessment of channel behavior during operation by observation. This determination shall include, where possible, comparison of the channel indication and/or status with other indications and/or status from independent channels measuring the same

parameter.

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0 l0 43 oF gl6 iEXT W more space de revinrod, use emowW NAC &m J86A s)11h A CHANNEL CALIBRATION is defined as the adjustment, as necessary, of the channel such that it responds within the required range and accuracy to known values of N input.

Nuclear Station Modification CN-10011, implemented on November 13, 1984, ,

originally added two loops of wide range NC temperature indications to the SSF.  !

Previously, the only temperature indication provided in the SSF was by the incore thermocouples [EIIS:XT]. These thermocouples provide indication to detect inadequate core cooling conditions, however, they do not indicate natural i circulation. During hot standby conditions natural circulation flow is needed i to avoid possibility of a steam void formation in the Reactor vessel [EIIS:VSL]

head region due to the stagnant conaitions in this well insulated area of the vessel. By adding the wide range NC temperature, the cooldown rate can be compared to a previously determined maximum allowable rate to assure that this steam void does not form and hamper natural circulation.  !

EVENT DESCRIPTION Nuclear Station Modification (NSM) CN-11103 will change the Unit I wide range NC  !

temperature indications from loops A and B to loops B and C.

On February 5, 1990 at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br />, during review of this NSM package for affected procedures, Operations Production Specialist A recognized that Enclosure 13.6 of PT/1(2)/A/4600/03A did not include the CHANNEL CHECK of wide ,

range NC temperature indications in the SSF, for either Units 1 or 2. Unit I was in Mode 6, Refueling, and Unit 2 was in Mode 1, Power Operation, at the time of discovery.

The SSF was declared inoperable at 1555 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.916775e-4 months <br /> on February 5, and an appropriate entry was made in the Technical Specification Action Item Log (TSAIL; item

  1. 309). Unit 2 entered the Action Statement of Technical Specification 3.7.13 which requires the SSF to be restored to OPERABLE within 7 days. Unit 1 was in Mode 6 in which SSF operability is not required.

A revision to PT/2/A/4600/03A, Enclosure 13.6, was developed, approved, and implemented on February 5. Unit 2 SSF wide range NC temperature indications were checked (as well as Unit 1, which was in Mode 6 with NC temperatures of approximately 125 degrees F). During the check, Unit 2 NC Loop A appeared to deviate more than 30 degrees F from the Control Room indication. Work Request 45530 OPS was initiated for Instrument and Electrical (IAE) to investigate. On February 7, IAE found the channel to be within tolerance and completed the work request without adjusting the indication (the indications deviated by 1 degrees F).

Unit 2 exited the Action Statement of Technical Specification 3.7.13 at 0900 hours0.0104 days <br />0.25 hours <br />0.00149 weeks <br />3.4245e-4 months <br /> on February 8, 1990.

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0 l0 0l4 oF 0l6 TEXT f# more ansce a meuww, use aanwerw NAC foem JetA W (1h CONCLUSION This incident is attributed to a Defective Procedure in that Enclosure 13.6 to PT/1(2)/A/4600/03A did not include the wide range NC SSF temperature indications on the list for monthly CHANNEL CHECKS. This violated the requirements of Technical Specification 4.7.13.6. These indications were overlooked when the original NSM package was reviewed for affected procedures. These indications were added to the SSF on November 13, 1984, just before Unit 1 initial criticality; the surveillance procedure was written approximately two months prior to that date.

The Unit 2 procedure has been revised to include the wide range NC temperature indications; the Unit 1 procedure will be revised prior to entering Mode 3, when SSF operability is required.

Other indications on the SSF Control Panel, Units 1 and 2, were verified to be properly included in Enclosure 13.6. A review of instrumentation required for SSF operability is being performed to determine if any addiitonal instrumentation should be included in the monthly CHANNEL CHECK and/or 18 month CHANNEL CALIBRATION; if needed, procedures will be revised appropriately. This report will be revised if additional instrumentation is identified.

The Unit 2 indications were found to be within the acceptance criteria when checked (they deviated by 1 degree F). Thus, no degradation of the wide range NC temperature indications in the SSF was detected. The ability of the Operators to take action in the SSF, as required by procedure, was not impaired.

A review of the Operating Experience Program (OEP) was performed in an attempt to identify previous events involving defective procedures associated with the SSF; including those that resulted from inadequate review of NSM packages. No previous events were identified within a 24 month period. This is not considered to be a Recurring Event.

CORRECTIVE ACTION l '

SUBSEQUENT

1) Enclosure 13.6 of PT/2/A/4600/03A was revised on February 5, 1990 to include wide range NC temperature indicators; the Unit 2 SSF wide range NC temperature indications were checked and compared to Control Room indications.

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2) Work Request 45530 OPS was written to investigate an apparent
discrepancy between SSF and Control Room indications for Loop A. The l- SSF indication was found to be reading accurately; no adjustments were performed.

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3) Other instrumentation on the SSF control panel was verified te be properly included in Enclosure 13.6 of PT/1(2)/A/4600/03A.

PLANNED

1) Enclosure 13.6 of PT/1/A/4600/03A will be revised to include wide range NC temperature indications for monthly CHANNEL CHECKS prior to Unit I reaching Mode 3; appropriate CHANNEL CHECKS will be performed.
2) A review of_ instrumentation required for SSF operability is being performed to determine if any additional instrumentation should be included in the monthly CHANNEL CHECK and/or 18 month CHANNEL CALIBRATIONS.
3) Appropriate procedures will be revised, if needed, to include additional SSF instrumentation in CHANNEL CHECKS and CHANNEL CALIBRATIONS.
4) This report will be revised if additional instrumentation is identified that needs to be included in procedures for monthly CHANNEL CHECKS or 18 month CHANNEL CALIBRATIONS.

SAFETY ANALYSIS The Standby Shutdown Facility (SSF) is designed as a minimally equipped back up to the Control Room and Auxiliary Shutdown Panels to be used in the event of a

l. major fire, sabotage, or a total loss of all AC power. It has enough controls to get either Unit 1 and/or Unit 2 to Mode 3, Hot Shutdown. ,

l The SSF provides sufficient controls and indications to achieve and maintain natural circulation in the NC System. The SSF encompasses alternate and independent means to achieve and maintain Mode 3 conditions by providing primary side volume and pressure control, secondary side volume and pressure control, L and the necessary instrumentation to monitor primary, secondary, and Reactor parameters.

l l In this event, it was discovered that the wide range NC temperature indications i

in the SSF had not been included in the monthly CHANNEL CHECK to verify l consistency with Control Room indications. When checked, the SSF indications were found to be reading within the specified band. These indications have been l periodically calibrated at the required intervals (18 months). No pre-existing l failure mode or mechanism has been identified that would render these l it dications more likely to fail or give inaccurate readings. Thus, it is coacluded that the Operator's ability to take action specified by the SSF L operating procedures was not impaired by this event.

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< The above conclusion notwithstanding, an assessment has been made of the effects of postulated _ inaccuracies in one or both channels of the SSF wide range NC 1 temperature indications. This assessment considered Operator action directsd by the procedure as based upon SSF indications and the Operator's ability to diagnose and respond to inaccurate indication. j Operating procedure OP/0/B/6100/13, Standby Shutdown Facility Operation, is used to direct Operator activities in the event the SSF is activated. This procedure includes 8 enclosures that direct Operator action under specified plant conditions. The principal activity of interest with respect to wide range NC temperature indication is that of verifying primary side natural circulation.

This action is called for in Enclosure 4.1 (4.2), Maintaining Unit 1 (Unit 2) in Hot Standby following a Fire Event, and in Enclosure 4.3 by reference to Enclosures 4.1 and 4.2. No other portions of this procedure involve indication of NC temperature to the Operators.

Step 2.19.1 of Enclosure 4.1 (4.2) directs the Operators in the SSF to verify that the NC System is subcooled by using Incore Thermocouples (T/Cs) and NC System pressure as read on SSF gauges and comparing to Data Book Curve 1.4.

(Guidance is provided'to adjust core temperature indications for changes in reference junction box temperature.) Operators are directed to take action in response to decreasing subcooling margin in verifying that potential NC System leakage points are isolated, to verify that pressurizer heaters [EIIS:EHTR] are energized, and to attempt to establish a better heat sink condition (by increasing secondary side inventory). As the Operators' assessment of subcooling margin is based upon Incore Thermocouple indications of NC temperature and NC pressure indications, postulated inaccuracies in wide range NC temperature indication would not impair their response.

Step 2.19.2 of Enclosure 4.1 (4.2) directs the Operators to verify that NC wide range (cold leg) temperature is at or near the saturation temperature for the Steam Generator [EIIS:HX] (S/G) pressure. It notes that S/G pressure is controlled by the S/G code safety relief valves while operating at the SSF.

Significantly, the Operators are not directed to take any action based upon this assessment of NC temperature. Had one or both channels of wide range NC temperature indication been indicating significantly low, e.g, more than 30

i. degrees F below true temperature, the Operators would have detected that wide l range NC temperatures below the saturation temperature for the existing S/G pressure are not physically possible and thus would have been alerted to the m inaccuracy. Conversely, wide range NC temperature indications significantly l above true temperature would be indicative of degraded / lost subcooling margin;

! again subject to confirmation with the incore thermocouples.

Thus, it is concluded that any inaccuracies in the wide range NC temperature indication available in the SSF would not have significantly impaired Operator action. The health and safety of the public were not affected by this event.

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