05000445/LER-2016-001, Regarding Safety Chiller Inoperable for Longer than Allowed by Technical Specifications

Regarding Safety Chiller Inoperable for Longer than Allowed by Technical Specifications

ML16245A232
Person / Time
Site:	Comanche Peak
Issue date:	08/22/2016
From:	Thomas McCool Luminant Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CP-201600797, TXX-16093 LER 16-001-00
Download: ML16245A232 (6)

LER-2016-001, Regarding Safety Chiller Inoperable for Longer than Allowed by Technical Specifications

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(ix) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i)
4452016001R00 - NRC Website

text

a Luminant CP-201600797 T)()(-16093 August 22, 2016 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Thomas P. McCool Site Vice President Thomas.McCool@Luminant.com Ref:

SUBJECT:

COMANCHE PEAK NUCLEAR POWER PLANT (CPNPP)

DOCKET NO. 50-445 LICENSEE EVENT REPORT 445/16-001-00 Luminant Power P 0 Box 1002 6322 North FM 56 Glen Rose, TX 76043 T 254 897 6042 c 817 776 0308 F 254 897 6652 10 CFR50.73 SAFETY CHILLER INOPERABLE FOR LONGER THAN ALLOWED BY TECHNICAL SPECIFICATIONS

Dear Sir or Madam:

Enclosed is Licensee Event Report (LER) 445/16-001-00, "Safety Chiller Inoperable For Longer Than Allowed by Technical Specifications," for Comanche Peak Nuclear Power Plant (CPNPP) Unit 1.

This communication contains the following new licensing basis commitment regarding CPNPP Units 1 and2.

Commitment No.

5321500

Description

The applicable Maintenance procedure will be revised before the next scheduled performance to have the equipment specific thermography inspection performed as a part of the maintenance restoration/post work activities so that an improper torque will be identified and corrected before the equipment is turned over to Operations.

The commitment number is used by Luminant Generation Company LLC for the internal tracking of CPNPP commitments.

If there are any questions regarding this report, please contact Mr. Gary L. Merka at (254) 897-6613 or Gary.Merka@luminant.com.

U.S. Nuclear Regulatory Conmlission TXX-16093 Page 2 of2 08/22/2016 Enclosure c - Kriss M. Kennedy, Region IV Margaret M. Watford, NRR Resident Inspectors, CPNPP Sincerely, Lurninant Generation Company LLC Th~ool

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2018 (06-2016)

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.

.,+

LICENSEE EVENT REPORT (LER)

Send comments regarding burden estimate to the FOIA, Privacy and Information Collections i

~~

Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by e-mail

~...

.I (See Page 2 for required number of digits/characters for each block) to lnfocollects.Resource@nrc.gov, and to the Desk Officer, Office of lnfonnation and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a (See NUREG-1022, R.3 for instruction and guidance for completing this form means used to impose an infonnation collection does not display a currently valid OMB control htti:i://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3Q number, the NRG may not conducl or sponsor, and a person is not required to respond to, the information collection.

3. PAGE Comanche Peak 05000 445 1 OF 4

4. TITLE Safety Chiller Inoperable For Longer Than Allowed By Technical Specifications

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED I

SEQUENTIAL I REV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR MONTH DAY YEAR NUMBER NO.

05000 FACILITY NAME DOCKET NUMBER 6

22 2016 2016 -

001 -

00 8

22 2016 05000

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)

D 20.2201

D 20.2203<a><3)(i)

D 50.73(a)(2)(ii)(A) 0 50.73(a)(2)(viii)(A) 1 D 20.2201(d)

D 20.2203(a)(3)(ii) 0 50.73(a)(2)(ii)(B)

D 50.73(a)(2)(viii)(B)

D 20.2203(a)(1)

D 20.2203(a)(4)

D so.73(a)(2)(iii)

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

D 20.2203(a)(2)(i)

D 50.36(c)(1)(i)(A) 0 50.73(a)(2)(iv)(A)

D 50.73(a)(2)(x)

10. POWER LEVEL D 20.2203(a)(2)(ii) 0 50.36(c)(1)(ii)(A)

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

D 73.71(a)(4)

D 20.2203(a)(2)(iii) o so.36(c)(2)

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

D 73.71 (a)(S) 0 20.2203(a)(2)(iv)

D so.46(a)(3)(ii) 0 50.73(a)(2)(v)(C)

D 73.77(a)(1) 100 0 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A)

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

D 73.77(a)(2)(i) 0 20.2203(a)(2)(vi)

[{] 50.73(a)(2)(i)(B) 0 50.73(a)(2)(vii)

D 73.77(a)(2}(ii) 0 50.73(a)(2)(i)(C)

D OTHER Specify in Abstract below or in SUMMARY OF THE EVENT, INCLUDING DATES AND APPROXIMATE TIMES On May 10, 2016, during a Unit 1 refueling outage Maintenance personnel (Utility, Non-Licensed) completed dash pot overload relay testing and re-installed the relays into the Unit 1, Train A Safety Chiller Motor Starter Panel [EllS:(KM)

(CHU)(DPT)(MSTR)]. The Maintenance personnel then re-terminated the Phase A, B, and C upper and lower cables to their respective dashpot overload relays, and should have torqued the bolted connections in accordance with the applicable Maintenance procedure.

On May 15, 2016, at 1625 the Unit 1, Train A Safety Chiller Technical Specification acceptance criteria was satisfactorily met and approved by the U1 Supervisor (Utility, Licensed) and the chiller was declared operable.

On May 28, 2016 at 0330Unit1 entered Mode 4, and per TS 3.7.19 the Unit 1, Train A Safety Chiller was required to be operable.

On June 9, 2016, at 1005 it was discovered during the performance of routine periodic predictive maintenance thermography by Engineering personnel (Utility, Non-Licensed) on the Unit 1, Train A Safety Chiller Motor Starter Panel that the Phase 'A' cable termination on the dashpot overcurrent relay had a significantly higher temperature reading than expected (950°F as opposed to a typical reading of about 90°F). The Unit 1, Train A Safety Chiller was shut down per the direction of tlie Shift Manager (Utility, Licensed) and the chiller was declared inoperable.

On June 22, 2016, an evaluation was completed that determined the Unit 1, Train A Safety Chiller had been inoperable from May 28, 2016 to June 9, 2016.

E. THE METHOD OF DISCOVERY OF EACH COMPONENT OR SYSTEM FAILURE, OR PROCEDURAL PERSONNEL ERROR During routine periodic predictive maintenance thermography activities, Engineering personnel (Utility, Non-Licensed) identified that the 'A' phase connection to the Unit 1, Train A Safety Chiller was at an elevated temperature.

II. COMPONENT OR SYSTEM FAILURES A. CAUSE OF EACH COMPONENT OR SYSTEM FAILURE Not Applicable - No other component or system failures were identified that contributed to this event.

B. FAILURE MODE, MECHANISM, AND EFFECTS OF EACH FAILED COMPONENT Not Applicable - No component or system failures were identified during this event.

C. SYSTEMS OR SECONDARY FUNCTIONS THAT WERE AFFECTED BY FAILURE OF COMPONENTS WITH MULTIPLE FUNCTIONS Not Applicable - No component or system failures were identified during this event.

D. FAILED COMPONENT INFORMATION

Not Applicable - No component or system failures were identified during this event.

Ill. ANALYSIS OF THE EVENT A. SAFETY SYSTEM RESPONSES THAT OCCURRED Not Applicable - No safety system responses occurred as a result of this event.

B. DURATION OF SAFETY SYSTEM TRAIN INOPERABILITY The Unit 1, Train A Safety Chiller was inoperable per Technical Specification 3.17.9 from May 28, 2016 to June 9, 2016 (approximately 222.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />).

C. SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT The Unit 1, Train A Safety Chiller was inoperable per Technical Specification 3.17.9 from May 28, 2016 to June 9, 2016.

During that time, the Unit 1, Train A Safety Chiller ran without any indication of abnormal performance or degraded function and the Train B Safety Chilled Water System was operable.

The safety significance of the identified condition is low, since the Train B Safety Chiller cooling function remained available during the subject period from May 28, 2016 to June 9, 2016, and no interim actions were required during the planned evolutions to reduce the effect on nuclear safety.

A probabilistic risk assessment of the inoperability of the Unit 1, Train A Safety Chiller found a non-risk significant effect on core damage frequency and large early release frequency. Based on the above considerations, this event had very low safety significance and there was no adverse effect on plant safety or on the health and safety of the public.

IV. CAUSE OF THE EVENT

The cause of this event was the restoration and post work activities by Maintenance personnel during a Unit 1 refueling outage did not ensure that the Unit 1, Train A Safety Chiller was properly configured per procedure and ready to be turned over to Operations. The improper torque resulted in one of the terminations experiencing significantly elevated temperatures once the equipment was returned to service and resulted in the Unit 1, Train A Safety Chiller being declared inoperable. Procedures and work practices contributed to this event. The Maintenance workers inadequately performed a procedure step directly after the termination torque performances directing them to ensure there were no loose electrical connections in the panel. The Maintenance procedure also currently only provides one sign-off step for the performance of six QIV termination torques. There were no training, communication, supervision, human-system interface, fitness for duty, or time/situational pressures associated with this event.

V. CORRECTIVE ACTIONS

The other three Safety Chillers were verified to have no thermal abnormalities. The Phase 'A' cable and dashpot relay were replaced and the Phase 'B' and 'C' dashpot relay terminations were retorqured. The applicable Maintenance procedure will be revised before the next scheduled performance to have the equipment specific thermography inspection performed as a part of the maintenance restoration/post work activities so that an improper torque will be identified and corrected before the equipment is turned over to Operations. The applicable Maintenance procedure will also be revised to include six component verification sign-off steps to verify each of the three line side and three load side terminations are torqued.

VI. PREVIOUS SIMILAR EVENTS

LER 1-14-003-00 was submitted on January 19, 2015, for the Unit 1, Train A Safety Chiller being inoperable for longer than allowed by Technical Specifications. However, the cause of the 2014 event was due to a different cause than this event. Page 4

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