United States Nuclear Regulatory Commission - Protecting People and the Environment

ACCESSION #: 9811300236


Post it [Trademark]brand fax transmittal Illinois Power Company
memo 7671 # of pages Clinton Power Station
To: From: P.O. Box 678
Co. CO. Clinton,IL 61727
Dept. Phone # Tel 217 935-6623
Fax # Fax # Fax 217 935-4632
Walter G. MacFarland IV
ILLINOIS POWER Senior Vice President and Chief Nuclear Officer
An Illinova Company U-603114
4F.140
 
November 25, 1999
 
Docket No. 50-461 10CFR21.21

Document Control Desk
Nuclear Regulatory Commission
Washington, D. C. 20555

Subject: 10CFR21 Report 21-99-049: Westinghouse DHP Circuit Breaker Refurbished by Nuclear Logistics, Incorporated Failed to Operate Due to Trip Latch Out-of-Adjustment and Incorrectly Sized Rachet, Lever Assembly Bushing

Dear Madam or Sir:

On September 30, 1998, the circuit breaker that had been installed at location 1AP09EE, tripped free during functional checking at Clinton Power Station (CPS). The breaker had been removed from location 1AP09EE, Drywell Water Chiller 1B, and was being prepared for installation in location 1AP07EF, Drywell Water Chiller 1A. Further inspection of the breaker found that the trip latch appeared to be out of adjustment and one ratchet lever assembly was an incorrect size. This condition rendered the breaker inoperable in the closing function. The breaker is a Westinghouse Model 50DHP350 circuit breaker. The breaker was originally purchased from the Braidwood station and refurbished by Nuclear Logistics, Incorporated, (NLI) prior to use at CPS.

Condition Report 1-99-10-001 was initiated to track an investigation and resolution of this issue. On October 1, 1998, Illinois Power (IP) determined this issue was potentially reportable under the provisions of 10CFR21.

IP is providing the following information in accordance with 10CFR21.21(d)(4). Initial notification of this matter will be provided by facsimile of this letter to the NRC Operations Center in accordance with 10CFR21.21(d)(3) within two days of the date the responsible officer signs this letter.

(i) Walter G. MacFarland, IV, Senior Vice President and Chief Nuclear Officer of IP, Clinton Power Station, Highway 54, 6 Miles East, Clinton, Illinois, 61727, is informing the Nuclear Regulatory Commission of a condition reparable under the provisions of 10CFR, Part 21.


11/25/1998 U.S. Nuclear Commission Operations Center Event Report Page 1
Power Reactor Event# 35082
Site: CLINTON Notification Date/Time: 11/25/1998
14:36 (EST)
Unit: 1 Region: 3 Event Date/Time: 11/25/1998
11:00 (EST)
Reactor Type: [1] GE-6 State: IL Last Modification: 11/25/1998
Containment Type: MARK III
NRC Notified by: RON FRANCE Notifications: MELVYN LEACH R3
HQ Ops Officer: LEIGH TROCINE VERN HODGE/RPM/PCEB NRR
NEIL DELLA GRECA R1
Emergency Class: NON EMERGENCY EDWARD MCALPINE R2
GARY SANBORN R4
10 CFR Section 21.21 UNSPECIFIED PARAGRAPH
Unit Scram Code RX Crit Init Power Initial RX Mode Curr Power Current RX Mode
1 N No 0 Cold Shutdown 0 Cold Shutdown

10 CFR 21 NOTIFICATION - WESTINGHOUSE DHP CIRCUIT BREAKER REFURBISHED BY NUCLEAR LOGISTICS, INCORPORATED, FAILED TO OPERATE DUE TO AN OUT-OF-ADJUSTMENT TRIP LATCH AND INCORRECTLY SIZED RATCHET LEVEL ASSEMBLY BUSHING

The following text is a portion of a facsimile received from the licensee:

"On September 30, 1998, the circuit breaker that had been installed at location 1AP09EE, tripped free during functional checking at Clinton Power Station (CPS). The breaker had been removed from location 1AP09EE, Drywell Water Chiller 1B, and being prepared for installation in location 1AP07EE, Drywell Water Chiller 1A. Further inspection of the breaker fond that the trip latch appeared to be out of adjustment and [that] one ratchet level assembly was an incorrect size. This condition rendered the breaker inoperable in the closing function. The breaker is a Westinghouse Model 50DHP350 circuit breaker. The breaker was originally purchased from the Braidwood station and refurbished by Nuclear Logistics, Incorporated, (NLI) prior to use at CPS."
"Condition Report 1-98-10-001 was installed to track an investigation and resolution of this issue. On October 1, 1998, Illinois Power (IP) determined this issue was potentially reportable under the provisions of 10 CFR [Part] 21."
"IP [provided this] information in accordance with 10 CFR 21.21(d)(4). Initial notification of this matter [was] provided by facsimile of [a] letter to NRC Operations Center in accordance with 10 CFR 21.21(d)(3) within 2 days of the date the responsible officer signs this letter." The letter was signed at approximately 1100 CST on November 25, 1998.
The licensee stated that the unit was not in a technical specification limiting condition for operation as a result of this issue.

U-603114
Page 2



(ii) The basic component involved in this condition is a Westinghouse Model 50DHP350, 4160-volt, circuit breaker installed in a Division 2 Class 1E circuit at location 1AP09EE, supplying non-safety-related Drywell Chiller 1B. The breaker was being prepared for installation in a Division 1 Class 1E circuit at location 1AP07EF, supplying non-related Drywell Chiller 1A
(iii) The circuit breaker was supplied to Clinton Power Station by the Braidwood station and was refurbished by NLI prior to installation at CPS.
(iv) Inspection of the circuit breaker identified that the trip latch appeared to be out-of-adjustment and one ratchet lever assembly bushing was an incorrect size. The incorrectly sized bushing appears to have caused the trip latch adjustment symptom. These deficiencies caused the breaker's ratchet lever assembly to interfere with the trip linkage as the breaker was closing. The interference with the trip linkage caused the circuit breaker to trip free (fail to close). This failure mechanism was intermittent, and therefore not experienced during previous testing of the circuit breaker at CPS.

Drywell Chillers 1A and 1B do not perform a safety function. The only safety function of the circuit breaker in those applications is to trip open. The "trip open" function of the circuit breaker was not adversely affected by the deficiencies, discussed in this report. However, this circuit breaker could have been installed in a number of other applications in the Divisions 1 and 2 safety-related 4160 volt busses which have a safety function to close. These applications affect equipment, such as any of the Residual Heat Removal System pumps, the Shutdown Service Water System pumps, the Emergency Diesel Generators, the Main Feeds, and the Reserve Feeds. If the circuit breaker had been installed in any of those applications, the safety function to close on demand for the applicable equipment may not have been met.

IP has concluded that this issue should be reported under the provisions of 10CFR21 on the basis that the deviations could have caused a failure of the, breaker to close during breaker operation and result in a loss of safety function for associated equipment loads.

(v) The apparent trip latch out-of-adjustment and incorrect ratchet lever assembly bushing conditions were identified on September 30, 1998 and determined to be potentially reportable under the provisions of 10CFR21 on October 1, 1998.
(vi) A total of three CPS circuit breakers were refurbished by NLI. All 3 bankers were initially rejected by Illinois Power at receipt inspection following the refurbishment by NLI due to various discrepancies. The breakers were returned to NLI for repair. The breaker discussed in this report was the only breaker installed at CPS after the NLI repair.

U-603114
Page 3

(vii) The breaker that tripped free has been shipped to another breaker services supplier for refurbishment. One of the other breakers was returned to CPS from NLI and is pending shipment to the other breaker services supplier for refurbishment. The third breaker was returned to CPS from NLI, and CPS personnel inspected and reworked that breaker.
A limitation has been imposed on NLI on the CPS Qualified Suppliers List, not allowing rework of Westinghouse DHP circuit breakers. Inspection criteria for checking the ratchet lever assembly bushings has been incorporated into the receipt inspection checklists for new and refurbished DHP model circuit breakers.
(viii) Additional information about circuit breaker refurbishment performed by NLI may be obtained by reviewing NUREG 0040, "Licensee Contractor and Vendor Inspection Status Report," Volume 22, Number 2, dated April-June 1999.


Additional information about this issue may be obtained by contacting R. A. Philipps, Plant Engineering at (217) 935-8881, extension 3464.

Sincerely yours,

Walter G. MacFarland, IV
Senior Vice President and
Chief Nuclear Officer
RSF/krk

cc: NRC Clinton Licensing Project Manager
NRC Resident Office, V-690
Regional Administrator, Region III USNRC
Illinois Department of Nuclear Safety
INPO Records Center
Nuclear Logistics, Incorporated


*** END OF DOCUMENT ***
Page Last Reviewed/Updated Thursday, March 29, 2012