05000456/LER-2012-004, Regarding Notice of Enforcement Discretion Received for Ultimate Heat Sink Temperature Exceeding Technical Specifications Requirements Due to Prolonged Hot Weather

Regarding Notice of Enforcement Discretion Received for Ultimate Heat Sink Temperature Exceeding Technical Specifications Requirements Due to Prolonged Hot Weather

ML12249A256
Person / Time
Site:	Braidwood
Issue date:	09/05/2012
From:	Enright D Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
BW120082 LER 12-004-00
Download: ML12249A256 (5)

LER-2012-004, Regarding Notice of Enforcement Discretion Received for Ultimate Heat Sink Temperature Exceeding Technical Specifications Requirements Due to Prolonged Hot Weather

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 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)(iii) 10 CFR 50.73(a)(2)(ix)(A) 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)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
4562012004R00 - NRC Website

text

Exelon Generation Company, LLC Braidwood Station 35100 South Route 53, Suite 84 Braceville,IL 60407-9619 September 5,2012 BW120082 www.exeloncorp.com U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. STN 50-456 and STN 50-457 Subject Licensee Event Report 2012-004 Notice of Enforcement Discretion Received for Ultimate Heat Sink Temperature Exceeding Technical Specifications Requirements Due to Prolonged Hot Weather The enclosed voluntary Licensee Event Report (LER) is being submitted.

There are no regulatory commitments contained in this letter. Should you have any questions concerning this submittal, please contact Mr. Chris VanDenburgh, Regulatory Assurance Manager, at (815) 417-2800.

Daniel J. Enright Site Vice President Braidwood Station

Enclosure:

LER 2012-004-00 cc: NRR Project Manager - Braidwood Station Illinois Emergency Management Agency - Division of Nuclear Safety US NRC Regional Administrator, Region '"

US NRC Senior Resident Inspector (Braidwood Station)

Illinois Emergency Management Agency - Braidwood Representative

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (10-2010)

, the NRC may digits/characters for each block) not conduct or sponsor, and a person is not required to respond to, the information collection.

/3. PAGE Braidwood Station, Unit 1 05000456 1 of 4

4. TITLE Notice of Enforcement Discretion Received for Ultimate Heat Sink Temperature Exceeding Technical Specifications ReqUirements Due to Prolonged Hot Weather

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED YEAR ISEQUENTIALIREV FACILITY NAME DOCKET NUMBER MONTH DAY YEAR NUMBER NO.

MONTH DAY YEAR Braidwood Station, Unit 2 05000457 FACILITY NAME DOCKET NUMBER 07 07 2012 2012. 004.

00 09 05 2012 N/A N/A

9. OPERATING MODE

11. THIS REPORT IS SUBMITIED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) o 20.2201 (b) o 20.2203(a)(3)(i) o 50.73(a)(2)(i)(C) o 50.73(a)(2)(vii) 1 o 20.2201 (d) o 20.2203(a)(3)(ii) o 50.73(a)(2)(ii)(A) o 50.73(a)(2)(viii)(A) o 20.2203(a)(1) o 20.2203(a)(4) o 50.73(a)(2)(ii)(B) o 50.73(a)(2)(viii)(B) o 20.2203(a)(2)(i) o 50.36(c)(1 )(i)(A) o 50.73(a)(2)(iii) o 50.73(a)(2)(ix)(A)

10. POWER LEVEL o 20.2203(a)(2)(ii) o 50.36(c)(1 )(ii)(A) o 50.73(a)(2)(iv)(A) o 50.73(a)(2)(x) o 20.2203(a)(2)(iii) o 50.36(c)(2) o 50.73(a)(2)(v)(A) o 73.71(a)(4) 099 o 20.2203(a)(2)(iv) o 50,46(a)(3)(ii) o 50.73(a)(2)(v)(B) o 73.71(a)(5) o 20.2203(a)(2)(v) o 50.73(a)(2)(i)(A) o 50.73(a)(2)(v)(C)

I25J OTHER o 20.2203(a)(2)(vi) o 50.73(a)(2)(i)(B) o 50.73(a)(2)(v)(D)

Specify in Abstract below or in Enforcement Discretion was requested to extend the Completion Time of Required Action A.1 by an additional 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> (Le., change the current six hour Completion Time to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) and to increase the limit of the average water temperature of the UHS in SR 3.7.9.2 to 102 degrees F to allow continued operation of Braidwood Station, Units 1 and 2, with the average water temperature of the UHS > 100 degrees F but <\\= 102 degrees F for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The Enforcement Discretion would end if the average water temperature of the UHS exceeds 102 degrees F or with the average water temperature of the UHS < 98 degrees F and on a declining trend.

At 1705 on July 7, 2012, approval of the request was verbally granted by the NRC, and on July 10, 2012, the written request for the Notice of Enforcement Discretion (NOED) was submitted. Compensatory actions in support of the NOED included limiting work on equipment, ensuring specific equipment and systems were protected and remained available, and as an operating compensatory measure, monitoring the Unit 2 refueling water storage tank to ensure it remained less than or equal to 95 degrees F.

At 2018 on July 7, 2012, the UHS temperature was below 99.9 degrees F, and TS 3.7.9 Condition A was exited.

Since TS 3.7.9 allows six hours to shut down Units 1 and 2 and the units were in Condition A for less than six hours, there was not a condition prohibited by the plant's TS.

This information is being transmitted to the NRC as a voluntary Licensee Event Report to report a condition that may be of potential generic interest for licensees and to describe the fact that while an NOED was granted and the TS Required Action time of six hours was met, the intent of TS 3.7.9 Required Action and Completion Time was not met.

t:.

Cause of Event

The cause of this event was due to the prolonged hot weather in the area. 2012 brought unprecedented hot weather (it tied a record triple-digit streak of three consecutive days from August 1947 and July 1911) and drought condition to the northern Illinois area. High temperatures during the daytime, in conjunction with little cooling at night and little precipitation, resulted in elevated UHS water temperatures. There are no controllable measures that can be taken to immediately reduce the temperature of the UHS, in that reduction of the heat input by derating the units would have a negligible short-term effect on the temperature of the UHS.

D.

Safety Consequences

There were no actual safety consequences impacting plant or public safety as a result of this event.

There was potential minimal safety consequence due to extending the Completion Time of Required Action A.1 by an additional 18 hours2.083333e-4 days <br />0.005 hours <br />2.97619e-5 weeks <br />6.849e-6 months <br /> and increasing the average water temperature of the UHS from <\\= 100 degrees F to

<\\= 102 degrees F. It was determined that a two degree F increase in UHS temperature had either no impact or an insignificant impact on the loss of coolant accident (LOCA) and non-LOCA results. Additionally, component assessments were performed and determined that components served by UHS would continue to perform satisfactorily despite a two degree F increase in UHS temperature. No adverse influences on risk were identified through examination of the probabilistic risk analysis model for the plant. Additionally, despite the hot weather conditions at the time, the average water temperature of the UHS exceeded the 100 degrees F limit for less than five hours.

Corrective Actions

There are no corrective actions for this event.

NRC FORM 36M (10-2010)

The conditions requiring the requested NOED are not typical and have not occurred in the past twelve years since a license amendment was implemented to increase UHS temperature to 100 degrees F. Currently available equipment margins and in one case operational compensatory actions were required to support the increase to 102 degrees F, which are not supportive of submittal of a permanent change to the TS through a License Amendment Request. This was discussed with the NRC during the NOED request, and the NRC agreed that a follow-up amendment is not needed.

Previous Occurrences

No previous, similar Licensee Event Reports were identified at the Braidwood Station.

~.

Component Failure Data

Manufacturer N/ANomenclature N/A Model N/A Mfg. Part Number N/A