ML14135A402

LER 14-003-00 for Fort Calhoun, Unit 1, Regarding Reactor Trip Due to Stator Water Cooling Leak During Maintenance

ML14135A402
Person / Time
Site:	Fort Calhoun
Issue date:	05/14/2014
From:	Cortopassi L P Omaha Public Power District
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LIC-14-0046 LER 14-003-00
Download: ML14135A402 (4)

Text

jjjjjjjj ----Omaha Public Power Oisll1t:t 444 South 16 th Street Mall Omaha, NE 68102-224 7 LI C-14-0046 May 14, 2014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Fort Calhoun Station , Unit No. 1 Renewed Facility Operating License No. DPR-40 NRC Docket No. 50-285 10 CFR 50.73

Subject:

Licensee Event Report 2014-003, Revision 0, for the Fort Calhoun Station Please find attached Licensee Event Report 2014-003, Revision O. This report is being submitted pursuant to 10 CFR 50.73(a)(2)(iv)(A), Specified System Actuation (RPS). There are no new commitments being made in this letter. If you should have any questions , please contact Terrence W. Simpkin, Manager, Site Regulatory Assurance, at (402) 533-6263. Sincerely, rk Loui . Cortopassi Site Vice President and CNO LPC/epm Attachment c: M. L. Dapas, NRC Regional Administrator, Region IV J. M. Sebrosky, NRC Senior Project Manager J. C. Kirkland, NRC Senior Resident Inspector NRC FORM 366 (02-2 014)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150*0104 EXPIRES: 01/31/2017 (02-2014)

Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> . .. LICENSEE EVENT REPORT (LER) Reported lessons leamed are incorporated into the licens i ng process and fed back to industry. Send comments regarding burden estimate to the FOIA , Privacy and Infonmation Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commiss i on , Washington, DC 20555-0001, or by i ntemet e-mail to Infocoliects.Resource@nrc.gov , and to the Desk Officer, Office of Infonmation and (See Page 2 for required number of Regulatory Affairs, NEOB-10202, (315()'0104), Office of Management and Budget , Washington, DC digits/characters for each block) 20503. If a means used to i mpose an infonmation collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor , and a person is not required to respond to , the information collection.

1. FACILITY NAME 2. DOCKET NUMBER 3. PAGE Fort Calhoun Station 05000285 1 OF 3 4. TITLE Reactor Trip Due to Stator Water Cooling Leak During Maintenance

5. EVENT DATE 6. LER NUMBER 7. REPORT DATE 8. OTHER FACILITIES INVO L VED YEAR I SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO. MONTH DAY YEAR 05000 FACILITY NAME DOC K ET NUMBER 3 17 2014 2014 003 -0 5 14 2014 05000 9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) D 20.2201 (b) D 20.2203(a)(3)(i)

D 50.73(a)(2)(i)(C)

D 50.73(a)(2)(vii)

D 20.2201 (d) D 20.2203(a)(3)(ii)

D 50. 73(a)(2)(ii)(A)

D 50.73(a)(2)(viii)(A) 1 D 20.2203(a)(1)

D 20.2203(a)(4)

D 50.73(a)(2)(ii)(8)

D 50.73(a)(2)(viii)(8)

D 20.2203(a)(2)(i)

D 50.36(c)(1)(i)(A)

D 50.73(a)(2)(iii)

D 50.73(a)(2)(ix)(A)

10. POWER LEVEL D 20.2203(a)(2)(ii)

D 50.36(c)(1)(ii)(A)

IZI 50. 73(a)(2)(iv)(A)

D 50.73(a)(2)(x)

D 20.2203(a)(2)(iii)

D 50. 36(c)(2) D 50.73(a)(2)(v)(A)

D 73.71(a)(4) D 20.2203(a)(2)(iv)

D 50.46(a)(3)(ii)

D 50.73(a)(2)(v)(8)

D 73.71(a)(5) 100 D 20.2203(a)(2)(v)

D 50.73(a)(2)(i)(A)

D 50.73(a)(2)(v)(C)

D OTHER D 20.2203(a)(2)(vi)

D 50.73(a)(2)(i)(8)

D 50.73(a)(2)(v)(D)

Spec i fy i n Abstract below or in NRC Form 366A 12. LICENSEE CONTACT FOR THIS LER LICENSEE CONTACT rELEPHONE NUMBER (Include Area Code) Erick Matzke 402-533-6855

13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT CAUSE SYSTEM COMPONENT MANU-REPORTABLE CAUSE SYSTEM COMPONENT MANU-REPORTABLE FACTURER TO EPIX FACTURER TO EPIX 14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MONTH DAY YEAR DYES (/fyes , complete 15. EXPECTED SUBMISSION DATE) IZI NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces , i.e., approximately 15 single-spaced typewritten lines) On March 17, 2014, at 12: 02 Central Daylight Time (COT), a turbine trip and subsequent reactor trip occurred while operating at nominal 100 percent power. Maintenance was in progress on the main generator stator cooling system when system inventory was lost resulting in an automatic turbine trip due to low system pressure. Immediate response by operat i ons personnel included implementing procedure emergency operating procedure (EOP) -00, Standard Post Trip Actions, and subsequent entry into procedure EOP-01, Reactor Trip Recovery. Based on plant system response this is considered an uncomplicated trip. The station determined that the root cause of the plant trip was that operational risk was not effectively identified or mitigated by individuals throughout the organization.

The leak was isolated shortly after the trip by fully removing the probe and closing the isolation valve. Fort Calhoun Station will be implementing the Exelon risk management procedure, WC-AA-104, Integrated Risk Management.

This procedure provides direction consistent with industry best practices, and requires individual review of each category of risk identification and mitigation. NRC FORM 366 (02-2 014)

NRC FORM 366A (02-2014)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 .... ; Ir t \ **..*. \(..1 LICENSEE EVENT REPORT (LER) CONTINUATION SHEET E s ti m a t e d burd en per r esponse to comp l y with this mandatory c ol l ection reques t 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send co mm ents regard i ng burden estimate to the FO I A. Pnvacy and Information Collections Bra n c h (T*5 F53). U.S. Nuclear R egu l atory Commission, Washington , DC 20555-0001 , or by in t e rn et e-mail to I nfocoilects

.Resource@nrc

.gov, and to the Desk Officer, Office of Information and R eg u l atory Affai rs , N E OB*10202 , (3150-0104), Office of Management and Budget, Wash i ng t on, DC 20503. If a means us ed to impose an information col l ection does not display a cu rren tly val id O MB contro l number, the NRC may not conduct or sponsor, and a person is not req ui red to respond to, the i n f ormatio n collection. 1. FACILITY NAME Fort Calhoun Station NARRATIVE BACKGROUND

2. DOCKET Y E AR 05000285 2014 6. LER NUMBER I SEQUENTIAL I NUMBE R -003 -REV NO. 00 3. PAGE 2 OF Fort Calhoun Station (FCS) is a two-loop reactor coolant system of Combustion Engineering design. EVENT DESCRIPTION On March 17, 2014, at 12:02 Central Daylight Time (COT), a turbine trip and subsequent reactor trip occurred while operating at nominal 100 percent power. Maintenance was in progress on the main generator stator water COOling system when system inventory was lost resulting in an automatic turbine trip due to low system pressure.

Immediate response by operations personnel included implementing procedure EOP-OO, Standard Post Trip Actions, and subsequent entry into procedure EOP-01, Reactor Trip Recovery.

Based on plant system response this is considered an uncomplicated trip. The loss of stator water cooling system inventory occurred during the removal of generator stator water cooling conductivity electrode number CE-5043-1 for calibration.

The installed safety knob did not prevent the probe from being removed from the system causing a stator water cooling leak. The technicians were unable to isolate the leak in time to prevent a turbine trip. The leak was isolated shortly after the trip by fully removing the probe and closing the isolation valve. At 1455 Central Daylight Time (COT), the Headquarter Operations Officer (HOO) was informed of the event per 10 CFR 50.72(b)(2)(iv)(B) (RPS Actuation) and 50.72(b)(3)(iv)(A) (Specified System Actuation (RPS)). This report is being submitted pursuant to 10 CFR 50.73(a)(2)(iv)(A), Specified System Actuation (RPS). CONCLUSION 3 Fort Calhoun Station's (FCS's) risk management processes and individual behaviors/mindsets were investigated to determine the root and contributing causes of this event. The RCA team reviewed FCS procedures, standards, and expectations regarding operational risk assessment.

Interviews were then conducted to determine if individual behaviors/mindsets and station culture was in line with established expectations.

The investigation concluded that there were shortfalls in individuals' mindsets and in the level of detail in the Station's risk management procedures.

Mindsets and accountability contributed to the cause of this event, and current Station procedures and guidelines are not sufficiently detailed to ensure workers are not in a knowledge based performance mode when asseSSing risk just prior to job execution.

Individual behaviors, mindset, and knowledge levels, as well as Station procedures and processes need to be at a level to ensure risk identification and mitigation actions are adequately evaluated prior to the job scheduled start time. The Station determined that the root cause of the plant trip was that operational risk was not effectively identified or mitigated by individuals throughout the organization.

NRC FORM 366 (02-2014)

NRC FORM 366A (02-2014)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017

.. ; \ ... ::!J LICENSEE EVENT REPORT (LER) CONTINUATION SHEET Estimated burden per response to comply with this mandatory collection request 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> . Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOIA, Pnvacy and Information Collections Branch (l-5 F53), U.S. Nuclear Regulatory Commiss i on , Washington, DC 20555-0001, or by internet e-mail to Infocoilects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-l0202, (3150-0104), Office of ManaQement and Budget, Washington, DC 20503. If a means used to impose an i nformation collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not requ i red to respond to, the information collection. 1. FACILITY NAME 2. DOCKET YEAR Fort Calhoun Station 05000285 2014 NARRATIVE CORRECTIVE ACTIONS 6. LER NUMBER J SEQUENTIAL I NUMBER -003 REV N O. 00 3. PAGE 3 OF The leak was isolated shortly after the trip by fully removing the probe and closing the isolation valve. Long Term Corrective Actions To correct the root cause Fort Calhoun Station will be implementing the Exelon risk management procedure, WC-AA-104, Integrated Risk Management.

This procedure provides direction consistent with industry best practices, and requires individual review of each category of risk identification and mitigation. SAFETY SIGNIFICANCE The loss of stator water cooling pressure caused a turbine trip to protect the main generator as designed.

Plant safety systems shutdown the reactor plant and support systems operated as designed. One non-safety bus was wetted and then deenergized as a precautionary measure. No equipment was damaged. The plant trip is considered uncomplicated. SAFETY SYSTEM FUNCTIONAL FAILURE This does not represent a safety system functional failure in accordance with NEI 99-02, revision 7. PREVIOUS EVENTS None. NRC FORM 366 (02-2014) 3