05000364/LER-1917-004, Regarding Turbine-Driven Auxiliary Feedwater Pump Steam Admission Valve Air Leak Resulted in a Condition Prohibited by Technical Specifications
| ML17362A039 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 12/22/2017 |
| From: | Madison D Southern Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NL-17-2123 LER 17-004-00 | |
| Download: ML17362A039 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2) |
| 3641917004R00 - NRC Website | |
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Southern Nuclear December 22, 2017 Docket No.:
50-364 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Dennis R. Madison Vice President - Farley Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2017-004-00 Joseph M. Farley Nuclear Plant 7388 North State Hwy 95 Columbia, Alabama 36319 334.814.4511 tel 334.814.4575 fax dnnadiso@southemco.com NL-17-2123 Turbine-Driven Auxiliary Feedwater Pump Steam Admission Valve Air Leak Resulted in a Condition Prohibited by Technical Specifications Ladies and Gentlemen:
In accordance with the requirements of 1 O CFR 50. 73(a){2){i)(B), Southern Nuclear Company is submitting the enclosed Licensee Event Report for Unit 2.
This letter contains no NRC commitments. If you have any questions regarding this submittal, please contact Mandy Ludlam at {334) 814-4930.
Respectfully submitted, r
D.R. Madison Vice President - Farley DRM/mml/cbg Enclosure: Unit 2 Licensee Event Report 2017-004-00 Cc:
Regional Administrator, Region II NRR Project Manager - Farley Nuclear Plant Senior Resident Inspector - Farley Nuclear Plant RTYPE: CFA04.054
Joseph M. Farley Nuclear Plant - Unit 2 Licensee Event Report 2017-004-00 Turbine-Driven Auxiliary Feedwater Pump Steam Admission Valve Air Leak Resulted in a Condition Prohibited by Technical Specifications Enclosure Unit 2 Licensee Event Report 2017-004-00
NRCFORM366 U.S. NUCLEAR REGULA TORY COMMISSION APPROVED BY 0MB: NO, 3160.0104 EXPIRES: 03/3112020 (04,2017)
, Iha NRC may not conduct or sponsor, and a person is not required to respond ta, lhe information colledion.
- 3. LER NUMBER Joseph M. Farley Nuclear Plant, Unit 2 05000-1 364 r::::i NUMBER NO.
I YEAR SEQUENTIAL REV
~-, 004 1*0
NARRATIVE
EVENT DESCRIPTION
On October 31, 2017, while In Mode 6 and at 0% power, with the Reactor Coolant System (RCS) at atmospheric pressure and 83 degrees Fahrenheit, the Turbine-Driven Auxiliary Feedwater (TDAFW) pump B-Train steam admission valve (!=118:
88/FCV) from the 2C Steam Generator failed to meet Technical Specification (TS) Surveillance Requirement (SR) 3. 7.5.5.
This SR v~rifies that the air stored in TDAFW pump steam admission valve accumulators is sufficient to open their associated train's steam. admission valves. Each steam admission valve has an air accumulator associated with it. The accumulators provide sufficient air to ensure the operation of the steam admission valves for the TDAFW pump during a.
loss of power or other failure of the normal air supply for a period of two hours.
During the performance of a flow scan analysis it was identified that the 8-,Train steam admission valve actuator was.
leaking by the a-ring. Although the steam admission valve would stroke open, the 2-hour acceptance criteria for using orily the associated accumulator could not be met. It is likely that the steam admission valve was inoperable longer than allowed by the Required Action Statement (7 days) following the spring 20~6 refueling outage when it last passed its
- associated surveillance..
EVENT ANALYSIS
While performing a flow scan of the TDAFW pump steam admission valve during the fall 2017 refueling outage, the actuator piston cylinder was discovered t<> be. leaking >10 psig per minute with acceptance criteria of <3 psig per minute.
An actuator rebuild was completed oil November 8, 2017. The steam admission valve actuator o-ring was replaced as part of the actuator rebuild. The o~ring failure was determined to be a cause of the event.
REPORTABILITY AND SAFETY ASSESSMENT
During the performance of a flow scan analysis it was identified that the B-Train steam admission valve actuator was leaking by the a-ring. Although the steam *admission valve would stroke open, the 2-hour acceptance criteria for using only*
the associated accumulator could not be met. Therefore, this condition is being reported in accordance with 10 CFR 50.73(a)(2)(0(B) as a condition prohibited by TS.
The Auxiliary Feedwater (AFW) system trains are configured into two flow paths, one for the motor-driven pumps and one for the turbine-driven pump. The AFW system is considered OPERABLE when the components and flow paths providing redundant AFW flow to the steam generators are OPERABLE. In addition, the TDAFW pump is required to be OPERABLE with redundant steam supplies from each of two main steam lines upstream of the main steam lsolation valves and shall be capable of supplying AFW to any of the steam generators via its associated flow path.
Although the B-Train steam admission valve accumulator was incapable of maintaining the steam admission valve
- open for two hours, the redundant A~Train steam admission valve was capable of performing the required function.
During the previous cycle, there were no Instances where both motor-driven AFW trains were rendered INOPERABLE at the same time. To further support continued operation of AFW; both trains of steam admission valves to the TDAFW pump have *emergency-air cOmpre*Ssors**capabte*<>t*beinQ aHQnec:fbY operatiOtlS *tci Support* motive operat1on-ot.-th8 ste*am** ----~ * -- -*-- -
admission valves. With the ability to operate the TDAFW pump from the A-Train steam admission valve, and having a redundant train of AFW (motor-driven), the safety function of the AFW system was met..
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NRC FORM 388A (04-2017)
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NRC FORM 386A (04-2017)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3160-0104 EXPIRES: 03/31/2020
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LICENSEE EVENT REPORT (LER)
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(See NUREG-1022, R.3 ror instruction and guidance for completing this form n11p;/AWJW nee gowcemt.ln!1illllLrtoc-eotteClions1nuregs1statrlli!1()22/Q/J EsUma!ed bwden per response to comply with 1h19 mandatory coneellon request 80 hoUJS. Reported lessons reamed are incorporated inlo the licensing process and red back ID Industry. Send.
comments regwdlng burden estimate lo the Information Services Brandt tT*2 F43); U.S, Nuclear' Ragulalory Commlaston, Washington, DC 20555-0001, or br e-mai to lnfoco!lects.R11$0urce@nrc.gnv, and 10 the Desk Officer. Office ol lnfOlfflalion and Regulatory Allainl, NEOB-10202, 13150-0104), Office of Managomenl and Budgo~ Washington, DC 20503. If a means used lo Impose en informabon coUacllon does nol display e currenlf)I wHd OMS conlrol number, the NRC mar nol conduct or sponsor, and e person Is not required lo respond to, the Information collection.
- 3. LER NUMBER Joseph M. Farley Nuclear Plant, Unit 2 05000-1 364 Cl NUMBER NO.
I YEAR SEQUENTIAL REV u-1 °04 1*0 NARRATIVE
CORRECTIVE ACTIONS
The actuator repair began on October 3.1, 2017, and was completed by m~ihtehance work order on November 8, 2017.
Further investigation of the preventive maintenance (PM) for diagnostic testing and actuator rebuild of the steam admission valves identified the current PM frequency was 6 years. This PM was last completed in November 2014. Based on the failure of the actuator piston o-ring, the site is evaluating frequency changes per the PM change process..
Following repair, the valve as-left testing acceptance criteria was per ASME OM Code 2001 Edition-2003 Addenda, Section ISTC-3310, "When a valve or its control system has been replaced, repaired, or has undergone maintenance that could affect the valves performance, a new reference value shall b.e determined or the previous value re-confirmed." The steam admission valve was functionally tested per plant procedures and was left in the acceptable range in accordance with the In-Service Testing (JST) program.
PREVIOUS SIMILAR EVENTS
No similar events were identified related to the accumulators or steam admission valves.
OTHER SYSTEMS AFFECTED:.
No other systems were affected, other than those listed in this LER.
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NRC FORM JSBA (04-2017)
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