ML20197A638

Special Rept 86-03:on 860405,pressurizer PORV BB-PCV-455A & RHR Suction Relief Valves EJ-8708A & EJ-8708B Lifted During RCS Pressure Transient.Caused by Control Valve Problems. Failed Controller Card Replaced

ML20197A638
Person / Time
Site:	Callaway
Issue date:	05/05/1986
From:	Randolph G UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
86-03, 86-3, ULNRC-1305, NUDOCS 8605120356
Download: ML20197A638 (4)

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Cataway Plant May 5, 1986 PRIORITY RO'JII M Mr. James G. Keppler I GS~~I hL2 Regional Administrator i d5T_ EA -

Office of Inspection & Enforcement 4" -

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t U.S. Nuclear Regulatory Commission FILE g Region III 799 Roosevelt Road Glen Ellyn, IL 60137

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ULNRC-1305

Dear Mr. Keppler:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 FACILITY OPERATING LICENSE NPF-30 SPECIAL REPORT 86-03 CHALLENGE TO OVERPRESSURE PROTECTION SYSTEM The enclosed Special Report is submitted pursuant to Technical Specification 3.4.9.3 and 6.9.2 concerning a challenge to the Overpressure Protection System.

h Yr G. L. Randolph Manager, Callaway Plant (l' Y MET / EA/TPS/ WK/drs Enclosure cc: Distribution attached k

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m me g 0 MaMg A#ess PO Box 620, Fulton, MO 65251

cc distribution for ULNRC-1305 Mr. Paul O'Connor Manager, Electric Department Office of Nuclear Reactor Regulation Missouri Public Service Commission U.S. Nuclear Regulatory Commission P. O. Box 360 Mail Stop P-316 Jefferson City, MO 65102 7920 Norfolk Avenue Bethesda, MD 20014 Mr. O. Maynard Kansas Gas and Electric Company P. O. Box 208 American Nuclear Insurers Wichita, KS 62701 c/o Dottie Sherman, Library The Exchange Suite 245 Mr. Nicholas A. Petrick 270 Farmington Avenue Executive Director, SNUPPS Farmington, CT 06032 5 Choke Cherry Road Rockville, MD 20850 Mr. J. H. Smith Bechtel Power Corporation Records Center SNUPPS Project Institute of Nuclear Power Operations 15740 Shady Grove Road Suite 1500 Gaithersburg, MD 20877-1454 1100 Circle 75 Parkway Atlanta, GA 30339 NRC Resident Inspector Mr. Merlin Williams D. F. Schnell (400) Supt. of Regulatory Quality &

R. J. Schukai (470) Administrative Services S. E. Miltenberger Kansas Gas and Electric Company J. F. McLaughlin P. O. Box 309 J. E. Davis (Z40LER) Burlington, KS 66839 (Z40LER) (w/c)

D. W. Capone /R. P. Wendling (470)

F. D. Field (470)

A. P. Neuhalfen A. C. Passwater/D. E. Shafer/D. J. Walker (470)

G. A. Hughes Z40.03 (QA Record)

J. M. Price R. D. Affolter W. R. Robinson M. E. Taylor H. Wuertenbaecher, Jr. (100)

S. L. Auston (470)(NSRB)

J. D. Schnack GLR Chrono 3456-0021.6 3456-0260 Z40ULNRC G56.37 N. Date (Sandra Auston) (470)

SPECIAL REPORT 86-03 CHALLENCE TO OVERPRESSURE PROTECTION SYSTEM The Overpressure Protection System was challenged on 4/5/86 at approximately 0121 CST while the plant was in Mode 5 (Cold Shutdown).

Pressurizer power operated relief valve (PORV) BB-PCV-455A and Residual Heat Removal (RHR) suction relief valves EJ-8708A and EJ-8708B lif ted during a Reactor Coolant System (RCS) pressure transient initiated as a result of control problems experienced with control valve BC-HV-8357A (Centrifugal Charging Pump 'A' discharge to Reactor Coolant Pump seals control valve).

Prior to the event, the RCS was in a solid plant condition with RCS pressure being maintained between approximately 380 to 405 p.s.i.g. and RCS temperature at approximately 104 degrees F. Centrifugal Charging Pump ' A' was in service providing RCS charging flow through the Boron Injection Tank and Reactor Coolant Pump seal injection flow through BG-HV-8357A. RHR trains 'A' and 'B' were in service.

At approximately 0120 the reactor operator attempted to close BG-HV-8357A however the valve did not properly respond. Approximately one minute later a 'PORV OPEN' annunciator was momentarily received on the main control board. A pressure spike was recorded on pressure recorder BB-PR-403 (RHR Pump 'A' Suction and PORV Control Wide Range Pressure Recorder) and the Alarm Printer indicated a 'RCS Water Pressure

- Hi' alarm. The reactor operator adjusted control valve BG-HCV-128 (RHR Cleanup to the Letdown Heat Exchanger Flow Hand Control Valve) to stabilize RCS pressure.

The cause of the pressure transient was determined to be excessive flow through BG-HV-8357A. The excess flow entered the RCS through the Reactor Coolant Pump seals and was sufficient to initiate the RCS pressure transient. The inability to reposition BG-HV-8357A was due to a failure of a controller card. The failure was determined to be a random card failure and the controller card was replaced on 4/9/86.

Based on receipt of the 'PORV OPEN' annunciator and available data, an engineering evaluation determined an RCS pressure transient of 97 seconds duration with a maximum RCS pressure of 463 p.s.i.g. did occur.

The overpressure limit of 530 p.s.t.g. required by Technical Specification Figure 3.4-4 was not exceeded. Pressurizer PORV BB-PCV-455A opened 74 seconds into the transient at a pressure very close to its setpoint (453.4 p.s.i.g.) and within its required tolerance. Pressure subsequently decreased to 350 p.s.i.g. within approximately 23 seconds. RCS pressure did not exceed the Ifft setpoint (467.4 p.s.i.g.) of pressurizer PORV BB-PCV-456A.

The duration of the event and previous surveillance testing indicates the RHR suction relief valves contributed minimally to mitigate the transient since RCS pressure was only above 445 p.s.i.g.

(lift setpoints of the RHR suction relief valves are 444 and 445 p.s.i.g.) for approximately eleven seconds.

SPECIAL REPORT 86-03 Page 2 The lift setpoints for BB-PCV-455A, BB-PCV-456A, EJ-8708A, and EJ-8708B were verified within tolerance by surveillance testing on 3/3/86, 3/4/86, 4/12/86, and 4/8/86, respectively. Since the setpoints of BB-PCV-455A and BB-PCV-456A were found within tolerance and EJ-8708A and EJ-8708B were tested satisfactorily after the transient, no additional testing is required.

Plant instrumentation / components functioned per design in accordance with the Technical Specifications to limit the duration and magnitude of the transient. Replacing the failed controller card and including its failure in the plant's instrument trending program is considered sufficient corrective action to prevent recurrence of this incident.

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