ML20236Q884

Responds to Violations Noted in Insp Repts 50-413/87-30 & 50-414/87-30.Corrective Actions:Methods for Evaluating Nuclear Instrumentation Sys (Nis) Setpoint Nonconservatisms Revised & Nis Channels & Pressure Switches Calibr

ML20236Q884
Person / Time
Site:	Catawba
Issue date:	11/13/1987
From:	Tucker H DUKE POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
NUDOCS 8711200342
Download: ML20236Q884 (7)

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DUKE POWER COMPANY f- " P.O. ISOX 33180 CHAltLOTTE, N.C. 28242 j HAL B. TUCKEN TELEPflONE d

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-November 13, 1987 1 q

U. S. Nuclear Regulatory Commission

- Attention: Document Contro1~ Desk Washington, D. C.'.20555 Subjects Catawba Nuclear Station Docket Nos. 50-413 and 50-414 IE Report 50-413/87-30 RII:PKV/MSL

Dear Sir:

Please find attached our response to the Violations 413,414/87-30-01, -02 and -03' {

.as identified'in the subject Inspection Report.

Very truly yours. I

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' Hal B. Tucker LTP/116/sbn j Attachment-k xc ,Dr.,J.' Nelson Grace, Regional-Administrator ]

U. S. Nuclear Regulatory Commission

l Region.II j

'11 Marietta Street, NW, Suite 2900 4 Atlanta, Georgia' 30323 l

-Mr. P. K. Van Doorn NRC Resident Inspector Catawba Nuclear Station 871120034g 973333 .

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DUKE POWER COMPANY  ;

RESPONSE T0' VIOLATION l 413, 414/87-30-01 Technical Specification (T.S) 2.2.1 requires that the Reactor Trip System Instrumentation and Interlocks setpoints shall be set consistent with the Trip

-Setpoint values shown in Interlock Setpoint less conservative than the value shown in the Allowable Values column of Table 2.2-1, adjust the'Setpoint consistent with the Trip Setpoint Value'and determine within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> that

. Equation 2.2-1 was satisfied for the affected channel.

Contrary to the above, on April 29, 1987, with all four channels of Power Range Neutron Flux Trip Setpoints less conservative than the Allowable Value of Table  ;

2.2-1, the licensee used incorrect values for Z and S in Equation 2.2-1 to 'j determine that Equation 2.'2-1 was satisfied and to conclude that the event was within the safety analysis.-

RESPONSE  !

(1) Admission or Denial of Violation Duke Power Company admits the violation.

-(2) Reasons for violation if admitted Technical Specification 2.2.1 requires that the Power Range NIS High Flux

. Reactor Trip setpoints be more conservative than 111.1% of Rated Thermal Power as evaluated by equation 2.2-1:

Z + R + S < TA

. j Where: Z = 4.56 (From Table 2.2-1)

R = 0.5 (Rack Drift Error) ,

S = 0.0 (From Table 2.2-2) i TA = 7.5 (From Table 2.2-1).

1 Per this T.S, the Power Range NIS is recalibrates whenever its indication is )

in error 2 2% from indicated Reactor Thermal Power. During the subject incident an error in the calculation of Reactor Thermal power ~

on the Plant ,

Operator Aid Computer created indications of thermal power _ 3% lower than ]

actual power level. Since this error was not realized at the time, j Operations personnel directed I and E personnel to recalibrates the Power )

Range NIS channels to' match the erroneous thermal power level. This j resulted in the Power range NIS being ~ 3% nonconservative with respect to I the High Flux Reactor Trip Setpoint.

1 The error in the Reactor Thermal power heat balance program was discovered l and corrected within two hours of the erroneous NIS recalibration and the I NIS was promptly recalibrates to restore the. required conservatism.

i In evaluating this event per equation 2.2-1 it was determined that the value l of "R" is assumed to be 0.5 (per station I and E personnel) and the value of i

- "S", or sensor error, is assumed to be zero for nuclear instrumentation L ]

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RESPONSE TO VIOLATION

'413,-'414/87-30-01 j Page'2 I

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.(fission chambers) per T.S.' Table 2.2-1. 'The value of "Z" provided in Table l 2.2-1 assumed only an error of.2%-in the nonconservative direction, so-a )

value of "Z" with an assumed error of > 3% was required to verify that the

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"TA" term had not been violated during the event, q j

i There had been considerable interest in the past in adopting a looser interpretation of the T.S. requiring a recalibration of the Power Range NIS l whenever mismatches-in excess of 2% with indicated reactor thermal power j exist. The. intent was to eliminate multiple recalibrations during power .i ascension following shutdowns or load decreases. To support this concept I the Nuclear Safety Group in Design Engineering derived a value of "Z" assuming a nonconservative error of 5%. This derivation was performed under the guidelines of the Westinghouse Setpoint Methodology for Protection Systems - Catawba Station (June, 1984) and was determined to be 5.96. 1 1

1 "Z" assures compliance with equation 2.2-1 for all' cases of This value of NIS Trip Setpoint nonconservatism up to 5%. It was therefore the contention

-of Station Personnel that no safety limit had been violated during the subject event during which the 3% nonconservatism existed.

Use of an unauthorized (fron T.S. standpoint) value of Z in evaluating oquation 2.2-1 was the reason for this violation. Despite a greater degree of confidence in the'value of Z derived by Nuclear Safety; the existing T.S.

' Table 2.2-1 value should have been invoked instead.

(3) Corrective Actions Taken and Results Achieved (A) Future evaluations.of NIS Setpoint nonconservatisms shall be performed using only values provided by Table 2.2-1.

(B)' Strict adherence to the T.S.'s with regard to recalibration of NIS channels whenever mismatches of 2 2% are noted will be continued.until such time'that a T.S. change is adopted to allow mismatches up to'5%

between NIS and thermal power indications.

(4) Corrective Actions to be Taken to Avoid Further Violations Actions taken in Section 3 above ensure avoidance of further violations.

'(5) Date of Full Compliance Duke Power Company is now in full compliance.

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DUKE POWER COMPANY RESPONSE TO VIOLATION 413, 414/87-30-02 10 CFR 50, Appendix B, Criterion XII as implemented by Quality Assurance Program (Duke 1-A, Amendment 10) Section 17.2.12 requires in part that measures be established to assure that instruments and measuring devices used in activities effecting quality are properly calibrated and adjusted at specified periods to maintain accuracy within necessary limits. Standing Work Request 006091 SWR specified a calibration period of 18 months (with a 25 percent grace period) for pressure switch ICAPSS131.

Contrary to the above, the licensee failed to establish adequate measures to assure that all instruments and measuring devices used in activities affecting quality were calibrated and adjusted at specified periods to maintain accuracy within necessary limits, in that pressure switch 1 CAPS 5131 was not calibrated from installation in April, 1984 until July 7, 1987, exceeding the specified l calibration and grace period. Twenty other safety-related instruments were also identified as having exceeded their specified calibration and grace periods.

RESPONSE

(1) Admission or Denial of Violation Duke Power Company admits the violation.

(2) Reasons for violation if admitted No evidence can be found to account for this condition. Construction records indicate ICAPS 5131 was installed in April, 1984 under F-13All6724.

No completed work request or calibration information could be located to support the initial calibration. However, the Licensee has reason to believe this calibration did occur because the circuit performed its functiec on July 17, 1986. A Standing Work Request (SWR) was identified and initiatol for this safety related instrument. Instruments identified in -

this report were not calibrated by the initial SWR, but were being phased into the work schedule by Integrated Scheduling, Planning and the Instrument and Electrical sections as manpower and plant conditions permitted.

(3) Corrective Actions Taken and Results Achieved Instrument 1 CAPS 5131 was checked and valved back in service under work i request 5749PRF on July 7, 1987. Instrument Details were reviewed to verify ,

if additional instruments should be added to the Instrument Startup I Checklist. The Instrument Valve Checklists were issued on the Auxiliary l Feedwater and Containment Spray systems to ensure all identified instruments l were in service.

(4) Corrective Actions to be Taken to Avoid Further Violations 1

The following pressure switches were added to IP/1(2)/A/3820/17A " Instrument Status Checklist": 1(2) CAPS 5131, 1(2) CPS 5141, 1(2) CAPS 5151. A Maintenance  !

Procedure will be written to define adequate calibration measures for new instrumentation added per NSM's. (Procedure to be completed by April 1, 1988.)

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RESPONSE TO VIOLATION 413, 414/87-30-02 Page 2 (5) Date of Full Compliance Duke Power Company will be in full compliance on April 1, 1988.

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RESPONSE TO, VIOLATION

-413, 414/87-30-03 Technical Specification 6.8.1 requires that written procedures shall be established, implemented, and maintained covering.the applicable procedures-recommended in' Appendix A to Regulatory Guide 1.33, Revision 2. Procedures 0P/0/A/6400/06, OP/1/A/6200/01, and OP/1/A/6250/02 require certain valves.as.

.specified in theirJenclosures to be locked'in position.

Contrary to the above, the following valves were observed not to be locked in Lposition (ni the indicated dates: 2RN938-September 1, 1987;'2RNC54-September 2, 1987; INV240-September 17, 1987; ICA34-September 21, 1987. None of these valves were found.out of their required position, but established procedures or.

administrative controls had not authorized the valves to be unlocked. In each case,'a chain and lock.was present'in the vicinity of the valve. However, no attempt hadlbeen made to lock the' chain around the handle.

RESPONSE: -

(1) Admission or Denial of Violation Duke Power Company admits the violation.

(2) Reasons for violation if admitted

'2RN938L -Reason for the violation is a procedure inadequacy in that the

. performance flow balance test does.not mention or cover the requirements of

!1ocked valves.. There was inadequate key' control used during the performance of this test for the RN. flow balance throttle valves. A contribution or primary 'ause c from personnel error may have occurred from the occasional adjustment of this' valve (which requires it to be unlocked) to regulate'the

. water flow to an overheating pump bearing. With inadequate key control, it is not possible to tell if this problem occurred.

ICA34 - Reason for the violation, we believe, is a procedure inadequacy in that the performance test procedures used during the time frame that the valve was found unlocked do not cover locked valve requirements.

2RNC54 - Reason for the violation is apparent personnel error. We believe the valve was left unlocked after a' flow balance test. The normal throttle was, opened fully and flow was still not high enough. The downstream

-isolation valve 2RNC54 was unlocked and checked fully open and not relocked.

.A removal and restoration sheet should be initiated covering the disposition

of the' lock in this situation. None was found.

INV240 - Reason.for violation is not specifically known. No recent condition'could be determined for the unlocking and operation of this valve.

. (3) = Corrective Actions Tak$m and Results Achieved All. valves were found in proper position and were immediately locked in that position.

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- RESPONSE TO VIOLATION l i 413,:414/87-30-03 l

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Corrective Actions'to'be Taken to Avoid Further Violations l

'(A) Review' locking controls by'an internal memo to.all groups who might )

manipulate valves, j (B) Nuclear Equipment Operators will be trained to re-emphasize locking valve procedures. j

-(C) ' Review this incident in detail at a Shift Supervisor's meeting to be conducted on November'13, 1987.

(D) Administrative key controls will be strengthened for locked throttled valves.

(E) The Performance Group will upgrade their procedures to address locked valve requirements.

-(F) The above corrective actions should prevent any re-occurrence of locked .

valves being left unlocked including unknown causes such as the case with 1NV240.

(5). Date'of' Full Compliance March 11, 1988.

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