05000390/FIN-2017004-01
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Finding | |
|---|---|
| Title | Misapplication of Technical Specification Limiting Condition for Operation 3.0.6 |
| Description | (Opened) Unresolved Item 05000390/2017004-01, Misapplication of Technical Specification Limiting Condition for Operation 3.0.6 Introduction. Inspectors identified an unresolved item (URI) associated with the misapplication of LCO 3.0.6 from the licensees TS as it pertains to the functionality of engineering safety feature (ESF) coolers serving as non-TS support equipment. The item is unresolved pending the outcome of engineering analyses being performed by the licensee to determine if the ESF coolers are necessary for TS-supported systems to maintain operability. In April 2010, TVA revised the bases for the Watts Bar Unit 1 TS by adding language to expand the scope of LCO 3.0.6. The licensee evaluated the TS bases revision against the 10 CFR 50.59 criteria and determined a license amendment was not required for the change.Prior to the TS bases revision, LCO 3.0.6 provided an exception for entering a supported systems conditions and required actions due to the inoperability of a TS support systemwhich by definition is a support system that has an associated LCO in the TS. Following the TS bases revision, the scope of LCO 3.0.6 was expanded to allow another exception pertaining to non-TS support systems (i.e., support systems with no associated LCO)that are 100 percent redundant and have the capability of individually supporting both TS trains. Specifically, the revision allows both of the supported TS trains to be considered operable when one of the 100 percent redundant, non-TS support system trains is declared non-functional (i.e., the non-TS support systems do not have to meet the single failure criterion resulting in the TS systems not meeting the same criterion). This revision to the TS bases manifests itself in the operation of both Unit 1 and Unit 2 ESF coolers that serve as 100 percent redundant, non-TS support systems for both trains of a TS system such as the emergency core cooling system (ECCS), containment spray (CS) system, and CCS. There are 12 plant areas with redundant trains of ESF coolers that support both trains of a TS system. In support of maintenance and in accordance with operating procedure 0-SOI-30.05, TVA routinely removed one of the redundant coolers from service exposing the twotrains of supported TS equipment to a single failure vulnerability. When the plant was in this configuration, the licensee considered both trains of the supported TS systems to be operable, and a TS LCO condition was not entered. The licensee justified operating in this manner based upon the interpretation of LCO 3.0.6, as previously discussed.Inspectors reviewed control room logs and identified multiple occasions where the plant was operated in this manner. In response, the inspectors reviewed the licensing basis for Watts Bar and determined there was a discrepancy between: (1) the General Design Criteria (GDC) found in Chapter 3 of the facilitys UFSAR; and (2) the operation of TS systems with the single failure criterion not being met.The GDC that pertain to ECCS, CS, and CCS all contain a requirement that the system safety function can be accomplished assuming a single failure. Inspection IMC 0326, Operability Determination & Functionality Assessments for Conditions Adverse to Quality or Safety (Agencywide Documents Access & Management System [ADAMS]Accession Number ML15328A099) contains guidance for inspectors to assist their review of licensee determination of operability and resolution of degraded or nonconforming conditions. IMC 0326 specifies that failure to meet a GDC is an entry point for an operability determination. Also, based on the definition of operability, IMC 0326 states: The operability requirements for an SSC [structure, system, and component] encompass all necessary support systems (per the TS definition of operability) regardless of whether the TS explicitly specify operability requirements for the support functions. In response to this inspection discovery, the licensee took two actions. First, in the nearterm, TVA revised the applicable ESF cooler operating procedure to require entrance into the appropriate LCO condition and required action statement when one of the ESF cooler trains is nonfunctional. Secondly, while the current design bases for the affected systems indicates that the coolers are required for system operability, TVA is performing engineering evaluations to determine if the support requirement can be eliminated under certain conditions. This effort is being tracked in TVAs corrective action program by CR 1357258. Based on the ongoing engineering evaluations, the inspectors have characterized this issue as a URI pending the outcome of the results. Once the evaluations are finalized, additional inspection can be performed to determine if a PD actually exists (e.g., TS violation). This is identified asURI 05000390/2017004-01, Misapplication of Technical Specification Limiting Condition for Operation 3.0.6. |
| Site: | Watts Bar  |
|---|---|
| Report | IR 05000390/2017004 Section 1R15 |
| Date counted | Dec 31, 2017 (2017Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.15 |
| Inspectors (proximate) | A Masters D Lanyi M Riches S Monarque P Cooper W Satterfield J Hamman J Nadel |
| INPO aspect | |
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Finding - Watts Bar - IR 05000390/2017004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Watts Bar) @ 2017Q4
Self-Identified List (Watts Bar)
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