IR 05000456/1989017

Insp Repts 50-456/89-17 & 50-457/89-17 on 890601-20. Violation Noted Re ECCS Operability.Major Areas Inspected: Inoperability of Centrifugal Charging Pump 2B While Manual Isolation Valve in Recirculation Line Shut

ML20245H848
Person / Time
Site:	Braidwood
Issue date:	06/22/1989
From:	Hinds J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20245H844	List: IR 05000456/1989017 ML20245H839
References
50-456-89-17, 50-457-89-17, NUDOCS 8906300120
Download: ML20245H848 (4)

Text

.

=;

. .

.. :

U.S. NUCLEAR REGULATORY COMMISSION

REGION III

Report.Nos.'50-456/89017(DRP);50-457/89017(DRP)

Docket Nos. 50-456; 50-457 License Nos. NPF-72; NPF-77 Licensee: . Commonwealth Edison Company Post Office Box 767 Chicago, IL 60690 Facility Name: Braidwood Station, Units 1 and 2 Inspection At: Braidwood Site, Braidwood, Illinois Inspection Conducted: June 1 through June 20, 1989 Inspectort: G. A. VanSickle T. M. Tongue T. E. Taylor WIWny~~

Approved By G. M. Hfnds, Jr., Chief 6M2/97 Reactor Projects Section IA D6te Inspection Summary Inspection from June I through June 20, 1989 (Report Nos. 30-456/89017(DRP);

50-457/89017(DRP))

Areas Inspected: Special safety inspection conducted by the resident inspectors concerning an event in which the 2B centrifugal charging pump was inoperable while a manual isolation valve in its recirculation line (2CV8479B) was shu Results: One apparent violation (failure to meet a Technical Specification requirement concerning emergency core cooling system [ECCS] operability) was identifie !

8906300120 890626

,

gDR ADOCK 05000436 PDC

__

.. - i

d i

DETAILS l Persons Contacted Commonwealth Edison Company (CECO)

!

• D. E. O'Brien, Technical Superintendent K. L. Kofron, Production Superintendent

• G. R. Masters, Assistant Superintendent - Operaticos

• D. E. Cooper, Regulatory Assurance Supervisor

• R. D. Kyrouac, Quality Assurance Supervisor

• W. B. McCue, Operating Engineer - Unit 0

• L. W. Raney, Nuclear Safety

• E. W. Carroll, Regulatory Assurar,

• M. R. Trusheim, Station Control Room Engineer

• P. Holland, Regulatory Assurance

• J. Wagner, Regulatory Assurance E. Lofdahl, Equipment Attendant T. Ciarlette, Equipment Attendant

• Denotes those attending the exit interview conducted on June 20, 198 . Purpose This inspection was conducted to review the circumstances related to the event in which the manual isolation valve in the recirculation line for the 2B centrifugal charging pump (2CV84798) was shut, thus rendering the 28 centrifugal charging pump inoperable from March 23 through June 1, 198 . Event Description and Chronology At approximately 11:45 a.m. on June 1,1989, immediately following a swap from the 2A to the 28 centrifugal charging pump, the operators noticed that there was no recirculation flow from the 2B pump (a local indication not available in the control room). Manual isolation valve 2CV84798 in the recirculation line for the 2B pump was found locked closed; the valve i was immediately opened and locked open. The normal position for valve

2CV8479B is locked ope As determined by a licensee investigation, 2CV8479B was mistakenly repositioned between 3:10 p.m., March 22 and 3:55 a.m., March 23, during the performance of letdown flow realignment per station procedure Bw0P CV-1 In cold shutdown (Mode 5) at the time, the licensee was aligning letdown flow to residual heat removal (RHR) Train A and securing flow l to RHR Train B. The procedure calls for valve 2RH8734A to be opened and valve 2RH8734B to be closed and locked closed; a station "B" man (equipment attendant) closed and locked closed 2CV8479B by mistak (2RH8734A and 2RH8734B are the RHR-to-chemical volume and control system l letdown isolation valves.) 2RH8734B and 2CV84798 are both 2" Kerotest.

l valves and are located near each other in the Unit 2 curved wall area, but their valve r. umbers are clearly marked on relatively large tag The operator who made the mistake did not sufficiently consult the valve !

tags to verify that he was shu'! lg the correct valv L_-_--__- _

__

_ _ _ _ _ __ __ _ ._ _ ___ _

.

,:

.

, . : - Improperly positioned 2RH8734B was discovered later on March 23 by another "B" man, who knew that only one RHR train was in service and that 2RH8734A and 2RH8734B should not be open at the same tim RH8734B was immediately locked shut. No station personnel recognized 1 that another valve may have been shut by mistak ;

Shortly before the above sequence of events, the Unit 2 locked equipment I surveillance (Bw0S XLE-R1) verified 2CV8749B as locked open. (XLE-R1_was  ;

conducted from March 21 to March 23.) Hence, the valve was mispositioned  ;

after it had been checked to be in the correct position. The XLE-R1 data sheet also showed that valve 2RH8734B was at first annotated with the words " flow path in use," and later verified as locked closed after it had been restored to its normal positio '

Shut valve zCV8479B isolated the 2B centrifugal charging pump' recirculation line.from March 23, 1989, until its discovery on June 1, 1989. Unit 2 entered Mode 3 (hot standby).on March 24 and operated in Mode 1, 2, or 3 during the remaining time.the recirculation line was isolated. Technical Specification' 3.5.2, requiring two operable emergency core cooling subsystems, applies during operation'in Modes 1, 2, and 3, and thus.was in effect throughout that period.

l Event Evaluation Locked shut valve 2CV8479B isolated a protective feature that ensures adequate minimum pump flow during ECCS operation under certain accident 1 conditions. -2CV84798 is in series with valve 2CV8116, a solenoid-operated valve which closes with a reactor coolant system pressure of 1448 psig (decreasing) and opens with a. pressure of 1643 psig (increasing). .This protective feature prevents deadheading that could

. damage the pump when it.is called on to perform its ECCS functio The protective feature of the centrifugal charging pump recirculation line is a modification in response to a concern originally identified by a Westinghouse 10 CFR Part F. notification of May 8,1980, In that report, Westinghouse noted that a centrifugal charging pump might not deliver sufficient flow to avoid pump degradation under the following conditions.:

The pump is called on to help mitigate the affect on the primary system during a secondary line break acciden The pressurizer power-operated relief valves (PORVs) are unavailable to relieve (PORVs are not safety-related equipment.) primary system pressur *

Primary pressure has reached the pressurizer safety valve lift setpoint and equals or exceeds the charging pump shut off hea *

The centrifugal charging pump recirculation line is isolated (automatically done in accordance with the existing plant design at the time of the Westinghouse letter).

Opening the recirculation line at higher pressures prevents deadheading  ;

the pump while such conditions exist. This modification was documented i

_ _ _ _ _ _ - _ _ _ _ - _ _ _ _ _ .

- _ . _

--

.

[ .

. 1

'y y .

4 ' q cin NUREG-1002, Supplement'l (Safety-Evaluation Report for-Braidwood)'.. =!

L ManuallyLisolating the recirculation line eliminates the pump's minimu flow protection, possibly making the: pump incapable of satisfying it ECCS function under the accident conditions described. Isolating its recirculation line thus rendered the 2B centrifugal charging pump inoperabl ~

Inoperability of centrifugal charging pump.2B for over two months with Unit 2 in Mode 1, 2, or 3 is.an apparent violation of Braidwood Technical Specification 3.5.2, which requires two operable ECCS subsystems, each

'

including an operable centrifuga1' charging pump, in Modes 1, 2, and Action statement a. of Technical. Specification.3.S.2. requires. restoration of ECCS operability within seven days or proceeding to hot standby (Mode 3) within six hours and. hot shutdown (Mode 4) within the fol hwing six hours, j . 5.- Licensee Corrective Actions The licensee immediately restored valve 2CV84798 totits normal. position after it was discovered locked shut. The licensee is. currently'

' conducting an evaluation of-the event, from which any long-term corrective actions will be identified.

L Conclusion In summary, the event apparently violates Technical Specification 3. concerning ECCS operability. The event is the third instance within the~

past two years in which ECCS operability was degraded beyond the time limit provided by the action statement. Although the other occurrences were considerably different in nature, each case involved mispositioning a valve in an ECCS subsyste The cause of this event was personnel error; the responsible "B" man

. simply locked shut the wrong valve during the performance of a routine evolution. The resident inspectors will monitor the licensee's long term corrective actio . Exit Interview (30703)

The inspectors met with the licensee representatives denoted in

- paragraph 1..during the inspection period and at the conclusion of the

- inspection on June 20, 1989. The inspectors summarized the scope and results of the inspection and discussed the likely content of this inspection report. The licensee acknowledged the information and did not indicate that any of the information disclosed during the inspection could be considered proprietary in natur I

, 4

~