ML20095E597

Special Rept 84-01:on 840718,PORVs BB-PCV-455 & BB-PCV-456 Lifted While Starting Reactor Coolant Pump B W/Rcs in Solid Plant Condition.Administrative Limit Established for Delta T Before Starting Reactor Coolant Pump

ML20095E597
Person / Time
Site:	Callaway
Issue date:	08/17/1984
From:	Miltenberger S UNION ELECTRIC CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
84-01, 84-1, ULNRC-909, NUDOCS 8408240315
Download: ML20095E597 (3)

Text

, y SPECIAL REPORT 84-01 CHALLENGE TO COLD OVERPRESSURE PROTECTION SYSTEM On 7/18/84 at 1835 CDT, the PORVs (Cold Overpressure Protection System) were challenged. PORVs BB-PCV-455 and BB-PCV-456 lifted while starting "B" Reactor Coolant Pump with the Reactor Coolant System (RCS) in a solid plant condition, RCS pressure at 350 psig, and steam generator secondary side water temperature higher than the RCJ Cold Leg temperature.

Prior to the PORVs lifting, initial conditions were established for starting a Reactor Coolant Pump (RCP) in order to satisfy a prerequisite for procedure ETT-SF-07014, " Control Rod Drive Mechanism Timing and DRPl System Test (Cold Shutdown)," The Shift Supervisor (SS) was aware of the facts that the Steam Generator secondary water was hotter than the RCS cold legs, the Technical Specification limitation on the delta T, and the physical consequences of starting a RCP with the existing delta T. In order to satisfy the Technical Specification limitation (specification 3.4.1.4.1 which prohibits a solid plant RCP start if the delta T between the Steam Generator secondary water and the RCS Cold Leg water is greeter than 50*F), the SS reviewed the wide range temperature recorder for loop "B" and found that the highest recorded temperature had not bEen above 170*F and that the existing temperature in the cold leg was about 120"F.

Based on the above conditions the SS concluded that the plant was in compliance with the Technical Specification limitations and plant operating procedures.

The SS was concerned about the potential for a Overpressure Transient, and therefore held an extensive pre-event discussion with the persennel who were to be involved. The pre-event discussion established a limit at which the RCP would be tripped if pressure increased rapidly.

This limit was set at 400 psi on the Number 1 Seal delta P instrument.

Also the discussion established the need to coordinate opening of the Chemical and Volume Control System Letdown Pressure Control Valve, BG-PCV-131, along with the RCP start, thereby limiting the pressure spike.

After the discussion, RCP "B" was started at 1835 and resulted O$ in an RCS pressure surge. In keeping with what was established in the M"-

oo pre-event discussions, the RCP was tripped when the Number 1 seal delta P indicated 400 psi. However, heatup and pressure increase continued min during the flow coastdown causing the PORVs to lift at the Cold Over-O in pressure Protection System setpoint of 450 psig. The lifting of the g PORVs, therefore, mitigated the pressure transient and no further oc immediate actions were taken, wa rM m Since the event, several corrective actions have been put in O$ place to help prevent recurrence. An Administrative Limit has been m a.C established for delta T between the Steam Generator secondary water and the RCS Cold Leg water to be less than 30*F before starting a RCP. This limitation has been inserted in the Precautions and Limitations sections of the associated Operating procedures. Also, emphasis will be increased on solid plant operation in licensing personnel training and retraining. This training will include a " lessons learned" section related to this specific event.

t; U NION EtecTmc COMPANY CA LLAWAY PLANT August 17, 1984 "'" a ^o o " = = = :

P O.BOM820 FULTON, MO. 652 51 James G. Keppler Regional Administrator USNRC Region III Office 799 Roosevelt Road Glen Ellyn, Illinois 60137 ULNRC-909 DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 SPECIAL REPORT 84-01 CHALLENGE TO COLD OVERPRESSURE PROTECTION SYSTEM

Dear Mr. Keppler:

The enclosed Special Report is submitted pursuant to Technical Specifications 3.4.9.3 and 6.9.2 concerning the pressurizer PORVs being used to mitigate a Reactor Coolant System pressure transient.

....E A J W -

S. E. Miltenberger Manager, Callaway Plant MET /JED/RRG/drs Enclosure cc: Distribution attached l

I

cr cc' distribution for ULNRC-909 James G. Keppler USNRC Region III Office 799 Roosevelt Road.

Glen Ellyn, IL 60137 American Nuclear Insurers c/o Dottie Sherman, Library The Exchange Suite 245 270 Farmington Aveue Farmington, CT 06032 Records Center Institute of Nuclear Power Operations Suite 1500 1100 Circle 75 Parkway.

Atlanta, CA 30339 NRC Resident-Inspector Missouri Public Service Commission D. F. Schnell J. F. McLaughlin J. E. Davis (Z40LER)

D. W. Capone R. L. Powers A. C. Passwater/D. E. Shafer/D. J. Walker G. A. Hughes W. R. Robinson (QA Record)

M. E. Taylor A. P. Neuhalfen R. A. McAleenan L. K. Robertson (470)(NSRB)

Merlin Williams, Wolf Creek SEH Chronc 3456-0021.6 Z40ULNRC G56.37 N. Date L- .