05000457/LER-2010-004, Regarding Unplanned Limiting Condition for Operation Entry Due to Low Header Pressure on the 2B Essential Service Water Pump

Regarding Unplanned Limiting Condition for Operation Entry Due to Low Header Pressure on the 2B Essential Service Water Pump

ML102980625
Person / Time
Site:	Braidwood
Issue date:	10/25/2010
From:	Shahkarami A Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BW100116 LER 10-004-00
Download: ML102980625 (5)

LER-2010-004, Regarding Unplanned Limiting Condition for Operation Entry Due to Low Header Pressure on the 2B Essential Service Water Pump

Event date:
Report date:
Reporting criterion:	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)(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
4572010004R00 - NRC Website

text

10 CFR 50.73 October 25, 2010 BW100116 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Unit 2 Facility Operating License No. NPF-77 NRC Docket No. STN 50-457

SUbject:

Licensee Event Report 2010-004 Unit 2 Unplanned Limiting Condition for Operation Entry Due to Low Header Pressure on the 2B Essential Service Water Pump The enclosed Licensee Event Report (LER) is being submitted in accordance with 10 CFR 50.73, "Licensee event report system", paragraph (a)(2)(i)(B), any operation or condition which is prohibited by the plant's Technical Specifications. On August 24, 2010, during performance of a surveillance on the 2B essential service water pump, essential service water system discharge pressure was reduced to below design requirements. 10 CFR 50.73(a) requires an LER to be submitted within 60 days following discovery of the event. Therefore, this report is being submitted by October 25, 2010.

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

Respectfully, Amir Shahkarami Site Vice President Braidwood Station

Enclosure:

LER 2010-004-00 cc: NRR Project Manager - Braidwood Station Illinois Emergency Management Agency - Division of Nuclear Safety US NRC Regional Administrator, Region III US NRC Senior Resident Inspector (Braidwood Station)

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150*0104 EXPIRES: 08/31/2010 (9*2007)

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

13. PAGE Braidwood Station, Unit 2 05000457 1 of 4

4. TITLE Unplanned Limiting Condition for Operation Entry Due to Low Header Pressure on the 2B Essential Service Water Pump

5. EVENT DATE

6. LER NUMBER

7. REPORT DATE

8. OTHER FACILITIES INVOLVED FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR

/ SEQUENTIAL / REV MONTH DAY YEAR N/A N/A NUMBER NO, FACILITY NAME DOCKET NUMBER 08 24 2010 2010 - 004 - 00 10 25 2010 N/A N/A

9. OPERATING MODE

11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply) 1 o 20,2201 (b) o 20,2203(a)(3)(i) o 50,73(a)(2)(i)(C) o 50,73(a)(2)(vii) 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) 94%

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) o OTHER o 20.2203(a)(2)(vi)

~ 50.73(a)(2)(i)(B) o 50.73(a)(2)(v)(D)

Specify in Abstract below or in the flow was to be set using the local flow indicator located around the corner from the control switch for the 2SX007 valve. The equipment number for the flow indicator was 2FI-SX031. Since the procedure step did not reference the ultrasonic flow meter or the location of flow element 2FE-SX147, the operators were unaware that the flow was to be obtained at the 2B SX pump. Additionally, the noun name for flow element 2FE-SX147 is 28 Essential Service Water Pump Suction Flow Element. This flow element noun name was not provided in the procedure. The operators could not find the flow element at the pump because the equipment name tag was tucked under the insulation blanket of the SX pipe. The operators were aware that flow could not be read from a flow element and incorrectly determined the flow element supplied indication to 2FI-SX031.

If the location of the flow element, the noun name, or the ultrasonic flow instrument was identified in the procedure step, the operators would have the appropriate cues that the local gauge 2FI-SX031 was the wrong gauge to use to set the flow.

D.

Safety Consequences

There were no actual safety consequences impacting plant or public safety as a result of this event. The SX system remained available during this transient.

The SX system supplies cooling water to transfer heat from various safety related and non-safety related systems and equipment to the ultimate heat sink. The SX system is needed in every phase of plant operations and, under accident conditions, supplies adequate cooling water to systems and components that are important to safe plant shutdown or to mitigate the consequences of the accident. Under normal operating conditions, the SX system provides component and room cooling (mainly via the CC system). During shutdowns, SX also ensures that the residual heat is removed from the reactor core. The SX system may also supply makeup water to fire protection [KP] systems and the steam generators via the auxiliary feedwater [BA] system for cooling of the plant.

Engineering determined the maximum flow from the event was 34,450 gpm, which is on the pump curve generated for the 2B SX pump from the pump vendor. Therefore, the pump remained in the tested region during performance of the surveillance testing and did not reach a run-out condition.

Evaluation of the low SX pressure effects indicates that both units and trains of SX were capable of mitigating the effects of design bases events. During the period where the low pressure condition of 65 psig existed, post-accident nominal flows to various equipment such as reactor containment fan coolers (RCFCs) [VA] and emergency diesel generator (DG) [EK] jacket water coolers would probably not be met since the throttle valve positions for this equipment is established at a nominal SX pump discharge pressure of 94 psig. In these conditions, operating procedures provide sufficient procedural guidance to perform appropriate actions to restore SX header pressure to maintain operability of the SX supported systems.

This event did not result in a safety system functional failure.

~.

Corrective Actions

The corrective action to prevent recurrence is to revise the SX pump surveillances to identify the total scope of the ASME surveillance in the purpose, and revise steps to specifically identify the use of the ultrasonic flow meter, equipment number and noun name, and location.

Previous Occurrences

2010 004 00 There have been no previous, similar events identified at the Braidwood Station in the past three years.

p.

Component Failure Data

Manufacturer N/ANomenclature N/A Model N/A Mfg. Part Number N/A PRINTED ON RECYCLED PAPER