05000390/LER-2003-006, Containment Spray Pump Inoperable Due to Open Breaker

Containment Spray Pump Inoperable Due to Open Breaker

ML033630764
Person / Time
Site:	Watts Bar
Issue date:	12/22/2003
From:	Lagergren W Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 03-006-00
Download: ML033630764 (8)

LER-2003-006, Containment Spray Pump Inoperable Due to Open Breaker

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3902003006R00 - NRC Website

text

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 William R. Lagergren, Jr.

Site Vice President, Watts Bar Nuclear Plant DEC 2 2 2003 10 CFR 50.73 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

In the Matter of Tennessee Valley Authority

)

Docket No. 50-390 WATTS BAR NUCLEAR PLANT (WBN) - UNIT 1 - FACILITY OPERATING LICENSE NPF LICENSEE EVENT REPORT (LER) 50-390/2003-006 This submittal provides Licensee Event Report 390/2003-006. This LER addresses an event that occurred on October 21, 2003, and resulted from a failure to properly restore the power supply to Containment Spray Pump 1B-B. This event is being reported under 10 CFR 50.73(a)(2)(i)(B).

There are no regulatory commitments associated with this letter. Should there be questions regarding this submittal, please contact Paul L. Pace at (423) 365-1824.

Sincerely,

Enclosure:

LER 390/2003-006 cc: See page 2

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U.S. Nuclear Regulatory Commission Page 2 DEC 2 2 2003 cc (Enclosure):

NRC Resident Inspector Watts Bar Nuclear Plant 1260 Nuclear Plant Road Spring City, Tennessee 37381 Ms. Margaret H. Chernoff, Project Manager U.S. Nuclear Regulatory Commission MS 08G9 One White Flint North 11555 Rockville Pike Rockville, Maryland 20852-2738 U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth St., SW, Suite 23T85 Atlanta, Georgia 30303 Institute of Nuclear Power Operations 700 Galleria Parkway, NW Atlanta, Georgia 30339-5957

Abstract

On October 21, 2003, WBN Unit 1 was returning to service after completion of the Cycle 5 refueling outage. The unit was in Mode 1 at approximately 36% reactor power, when it was established that 6.9KV Shutdown Board breaker, 1-BKR-72-10, was not connected and was not capable of supplying power to the Containment Spray System (CSS) Pump 1 B-B. In accordance with LCO 3.6.6, "CSS," Pump 1 B-B is required to be operable in Mode 4.

The restoration of the breaker should have been performed in accordance with Section 5.2.8 of General Operating (GO) Instruction 1, "Unit Startup from Cold Shutdown to Hot Standby," and verified in accordance with Step 6 of Appendix B, "Mode 5-to-Mode 4 Review and Approval," of GO-1. Due to the CSS pump not being operable as the unit transitioned from Mode 5 to Mode 1, the mode change restrictions of LCO 3.0.4 were not met. The total time CSS Pump lB-B was inoperable was approximately 113.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Considering this, Action A of LCO 3.6.6, "CSS,"

requires that an inoperable CSS train be restored within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. When this action is not met, Action C.1 requires that the Unit be in Mode 3 in 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. Neither of these actions were met. The failure to comply with the requirements of LCO 3.0.4 and LCO 3.6.6 is being reported as a violation of the Technical Specifications in accordance with 10 CFR 50.73 (a)(2)(i)(B).

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(If more space is required, use additional copies of (If more space is required, use additional copies of (if more space is required, use additionalcopies of NRC Form 3664)

III. 2. The inadequate verification that the CO had been removed. This verification is required by Step 6 of Appendix B,

'Mode 5-to-Mode 4 Review and Approval," of GO-1.

TVA's assessment of the first error found that the individual who approved Step 5.2.8 assumed the CSS was operable because he was aware it had been used during outage evolutions. For the second error, the assessment found that verification was performed by a walkdown of the Main Control Boards to verify the 00 had been removed. In addition a clearance report was reviewed to establish that required approvals had been made.

The following factors contributed to this issue:

1. The Main Control Room (MCR) handswitch indicating lights were illuminated because the control power fuses were not removed. Thus the Operator could not use the lights as a means to determine that the breaker was disconnected.

2. The Integrated Computer System (ICS) Bypassed and Inoperable Status Indication (BISI) system was used to determine that the breaker was disconnected. This system is available to the Operations staff on the ICS.

However, there was no requirement for it to be used to verify the configuration of a system.

3. SOI-72.01 requires that the proper liquid level in the header be verified. However, the instruction only addressed placing the pump in service the line was required to be filled.

Considering the above, the root cause of this event was determined to be:

An erroneous assumption that the Containment Spray system was configured normal due to the presence of control power lights on the MCR handswitch, use of the system during the outage for various activities, and the verification of the standby alignment via the removal of the CO.

IV. ASSESSMENT OF SAFETY CONSEQUENCES

The breakers feeding the two trains of the Containment Spray System (CSS) pumps were disconnected in preparation for the Unit 1 Cycle 5 refueling outage. This action was performed in accordance with Step 3 of Appendix C, 'Mode 4-to-Mode 5 Activities," of General Operating (GO) Instruction 6, "Unit Shutdown from Hot Standby to Cold Shutdown." However, during the startup process after the outage and subsequent re-entry into Mode 4, the breaker for CSS Pump 1 B-B was not reconnected. The restoration of the breaker should have been performed in accordance with Section 5.2.8 of General Operating (GO) Instruction 1, hUnit Startup from Cold Shutdown to Hot Standby," and verified in accordance with Step 6 of Appendix B, Mode 5-to-Mode 4 Review and Approval," of GO-1.

Two CSS trains are required to be operable in Modes 1, 2, 3, and 4. However, only one train is required to operate following a design basis event for the CSS to perform its design basis accident mitigation function. The Operation's Logs were reviewed to assure that the opposite train, CSS Pump A-A, was available for accident mitigation during the time period when the breaker for the 1 B-B pump was disconnected. This review also included Train A of the Emergency Raw Cooling Water (ERCW - EIIS Code BI) system and Train A of the Emergency Diesel Generators (EDGs - EIIS EK), as these systems would be required to support operation of CSS Pump A-A The review of the log was performed to determine if the following Technical Specification (TS) Limiting Conditions for Operations (LCOs) were entered during the time period between Mode 4 re-entry on October 16, 2003, at 23:48 and October 21, 2003, at 09:35 when CSS Pump 1 B-B was returned to operable status:

(fIf more space is required, use additional copies of NRC Form 366A) (17)

IV. LCO 3.6.6, CSS," for Train A of the CSS.

LCO 3.7.8, ERCW," for Train A of the ERCW.

LCO 3.8.1, AC Sources - Operating," for Train A of the EDGs.

The review determined that there were no entries into the three LCOs and based on this, was concluded that Train A of the CSS was operable and available for the system to perform its design basis accident mitigation function. Therefore, the safety consequences of this event were not significant.

V.

CORRECTIVE ACTIONS

A.

Immediate Corrective Actions

1.

Breaker, 1-BKR-72-10, was reconnected to return CSS Pump B-B to service.

2.

The alignment of both trains of the CSS was verified in accordance with Section 5.0, Standby Readiness,"

of System Operating Instruction SOI) 72.01, Containment Spray System."

B.

Corrective Actions to Prevent Recurrence - (TVA does not consider these items to constitute regulatory

commitments

TVA's corrective action program tracks completion of these actions.)

1.

The Operator involved in the event was counseled for not verifying assumptions.

2.

The event was covered with all Operations' crews stressing the need to verify configuration versus assuming that it is in the correct configuration.

3.

The Unit Supervisor involved in the event was counseled to ensure computer generated alarms are responded to as appropriate.

4.

The Operations staff will receive additional training on the use of the ICS BISI computer function and s practical uses.

5.

Operations has revised the general operating procedure to strengthen the requirements to verify the CSS is configured correctly following release of a Caution Order.

VI.

ADDITIONAL INFORMATION

A.

Failed Components There were no failed components involved in this LER.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)

LICENSEE EVENT REPORT (LER)

1. FACIUTY NAME

2. DOCKET

6. LER NUMBER

3. PAGE YERl SEQUENTU L

NUMBER 6

OF 6

Watts Bar Nuclear Plant, Unit 1 05000390 2003 --- 006

--- 01

17. (If more space is required, use additionalcopies of NRC Form 366A)

B. Previous LERs on Similar Events The following is a listing of the LERs which have been initiated for Watts Bar due to violations of the Technical Specifications:

LER Number

Cause of Event

1.

390/1996-02 The instruments relied on by the operators to verify Surveillance Requirement 3.5.1.2 were inaccurate.

2.

390/1996-24 The detail contained in the Maintenance configuration log of a Work Order was inadequate to ensure the component was restored to the proper configuration.

3.

390/1997-16 This LER documented a situation where the handswitches for both fuel oil transfer pumps for the 2B-B Emergency Diesel Generator were mispositioned. After a thorough review the specific cause of the mispositioned switches could not be determined.

4.

390/2000-02 This LER resulted from a change in the scope of a Problem Evaluation Report which was implemented without appropriate reviews and approvals.

As indicated in Section IlIl, Cause of Event," LER 390/2003-06 resulted from an erroneous assumption that the CSS was operable prior to the planned mode changes. Based on the above comparison of the causes of previous events, the recurrence controls established for the listed LERs would not have prevented the Technical Specification violation documented by LER 390/2003-06.

C. Additional Information

None.

D. Safety System Functional Failure This event did not involve a safety system functional failure as defined in NEI-99-02, Revision 0.

E. Loss of Normal Heat Removal Consideration This event is not considered a scram with loss of normal heat removal.

VII.

COMMITMENTS

None NKL; IOHM 366A (1-2001)