05000219/FIN-2009007-03
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Finding | |
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Title | Declassification of the Service Water System from ASME Class 3 to a non-Class Designation |
Description | An unresolved item (URI) was identified because additional NRC review and evaluation is needed to determine the applicability of NRC RG 1.26 to the SW system, and therefore, the acceptability of modification 08-00041. The team plans to request additional guidance and clarification from NRCs Office of Nuclear Reactor Regulation (NRR). The SW system is classified as a non-safety related system at Oyster Creek. The SW system cools the reactor building closed cooling water (RBCCW) system, which in turn, cools the shutdown cooling (SDC) and spent fuel pool cooling systems. Exelon stated that the function to remove residual heat from the reactor, while normally performed with the SDC system, can be accomplished using safety related equipment. Specifically, the electromatic relief valves, the core spray system and the containment spray/emergency service water systems are all safety related systems that can perform this function, and the use of these systems is documented in a station procedure. The function to remove residual heat from the spent fuel storage pool is accomplished by the fuel pool and augmented fuel pool cooling systems. The RBCCW,SDC and spent fuel pool cooling systems are also classified as non-safety related systems. Over the last several years, Exelon has experienced underground leakage events from SW system piping. In response, they replaced sections of the affected underground piping. To date, all repair and testing of the piping has been performed in accordance with the ASME Code due to the ASME Class 3 designation of the SW piping. As documented in Exelons ISI Program Plan, the SW system piping had been classified as an ASME Class 3 system using NRC RG 1.26 as guidance. The purpose of this classification effort was to identify those systems subject to In-service Inspection (ISI) and In-service Testing (IST) requirements. As stated in Section 1.8 of the UFSAR, across-reference with design criteria (including NRC RG 1.26), the Systematic Evaluation Program, and the NRC Safety Evaluation for Oyster Creek (NUREG 1382) was conducted. The safety evaluation documents Exelons conformance to NRC RG 1.26.In January, 2008, Exelon implemented modification 08-00041 to reclassify the SW system from an ASME Section XI Class 3 system to a non-Class system, concluding that the SW system piping classification (early 1970s) was overly conservative. The declassification allows removal of the SW system from the ISI and IST programs and also allows non-ASME code repairs. The team questioned Exelon on the declassification of the SW system piping due to the functions provided by the SW system, such as removal of residual heat from the reactor and from the spent fuel storage pool via the RBCCW system, with the SDC system and spent fuel pool cooling systems, respectively. The team referenced NRC RG 1.26 and the UFSAR to assess whether the SW system was an important to safety system and therefore, should not have been declassified to a non-Class designation. In particular, Section C.2, Quality Group C, of NRC RG 1.26 states, in part, that cooling water or portions of those systems important to safety that are designed for residual heat removal from the reactor and from the spent fuel storage pool correspond to ASME Class 3components.In response to the teams questions, Exelon stated, based on the introduction section of NRC RG 1.26, that the guide is only applicable to safety related structures, systems, and components; and therefore, does not apply to the SW system because it is not safety related. Specifically, the 10 CFR 50.59 Screen for modification 08-00041 stated that NRC RG 1.26 specifically addresses nuclear safety related components; and the SW system is not safety related and does not perform any functions that are important to safety, therefore it is not Quality Group A, B, or C; therefore, it is not necessary that the SW system be within the ASME Section XI ISI Program. In addition, the team noted that in the safety evaluation screen associated with modification 08-00041, Exelon stated that important to safety is analogous to nuclear safety related. This issue will be opened as a URI in order to determine the applicability of NRC RG1.26 for classifying the Oyster Creek SW system, and the acceptability of modification08-00041. (URI 05000219/2009007-03, Declassification of the Service Water System from ASME Class 3 to a non-Class Designation |
Site: | Oyster Creek |
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Report | IR 05000219/2009007 Section 1R17 |
Date counted | Jun 30, 2009 (2009Q2) |
Type: | URI: |
cornerstone | Mitigating Systems |
Identified by: | NRC identified |
Inspection Procedure: | IP 71111.17 |
Inspectors (proximate) | L Scholl R Moore S Pindale M Balazik L Doerfleinj Kulps Barr R Nimitz J Nicholson R Bellamy J Ambrosini O Masnyk-Bailey S Hammann |
CCA | H.7, Documentation |
INPO aspect | WP.3 |
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Finding - Oyster Creek - IR 05000219/2009007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Oyster Creek) @ 2009Q2
Self-Identified List (Oyster Creek)
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