05000461/FIN-2010002-06
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Finding | |
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| Title | Questions Regarding 10 CFR 50.59 Evaluation for CPS Procedure 3711.01 Involving Operations with the Potential to Drain the Reactor Vessel |
| Description | The inspectors reviewed evaluation CL-2010-E-001, CPS Operations with the Potential to Drain the Reactor Vessel (OPDRV), Revision 0, for compliance with 10 CFR 50.59, Changes, Tests, and Experiments. The inspectors have questions remaining whether the implementation of the new procedure would create the possibility for an accident of a different type than any previously evaluated in the UFSAR. This issue is considered to be an Unresolved Item pending additional review by the inspectors. On January 11, 2010, the licensee approved CPS 3711.01, which established the definition of an OPDRV for use in determining the applicability of several TS requirements while in Modes 4 and 5. Prior to the procedure approval, an evaluation, CL-2010-E-001, was performed by the licensee to address the criteria of 10 CFR 50.59(c)(2). In its evaluation, the licensee concluded that none of the eight criteria were applicable under this requirement to obtain a license amendment pursuant to 10 CFR 50.90 prior to implementing the new procedure. Specifically, Criterion (v) which requires a license amendment prior to implementing a change that creates a possibility for an accident of a different type than any previously evaluated in the UFSAR was determined to not apply. Upon review of the implementation of CPS 3711.01, the inspectors identified a number of credible accident scenarios that were introduced by this procedure change and not previously evaluated in the UFSAR. The Clinton UFSAR analyzed a LOOP for only at-power conditions. This LOOP could also occur in Modes 4 and 5 at similar frequency and could have significance due to the implementation of the new procedure. Evolutions with non-isolable RCS leakage below 5 gpm, and up to 420 gpm with a single method of isolation were made procedurally acceptable and not to be considered an OPDRV by the licensee. Evolutions with RCS leakage up to these values could occur simultaneously with the inoperability of all ECCS and still remain in compliance with TS 3.5.2, which addresses the ECCS requirements for Modes 4 and 5. In addition, coincident with this scenario, neither primary nor secondary containment was required to be set according to TS 3.6.1.1 and 3.6.4.1, respectively. If a LOOP were to occur in this condition during refueling, it could possibly be of significance. No evaluation was performed by the licensee to determine how much time might be available for operators to respond prior to uncovering irradiated fuel in the upper containment pool for such a scenario. Rough estimations performed by the inspectors found the available time for operator response to be no more than six hours. In EC 376912, the licensee evaluated the time it would take to drain down to the reactor vessel flange with the new RCS leakage limits defined in CPS 3711.01 and found there to be greater than 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br /> for operators to respond. This evaluation did not consider the potential for uncovering irradiated fuel in the upper containment pool. The licensees evaluation accepted a non-controversial basis in the industry in defining an OPDRV. That definition specified that an open penetration that has the potential to uncover irradiated fuel is an OPDRV. Irradiated fuel would necessarily include any fuel that could be uncovered in the upper containment pool. Other credible scenarios introduced by the procedure change include the possible failure of administrative controls to preclude inadvertent withdrawal of a control rod that is being relied upon to isolate leakage for a removed control rod drive mechanism; or a fuel handling accident, which could result in a load movement disturbing the proper seating of such a control rod. The inspectors noted previous examples of failures of administrative controls similar to those relied upon in CPS 3711.01 to eliminate the potential for an accident. Notably during the recent refueling outage, on January 18, 2010, a location error occurred when the licensees refueling team discovered they had removed the incorrect control rod double blade guide. This incident occurred despite several procedural and human performance error prevention tools that were utilized. In addition, during the February 2008 refueling outage only a good questioning attitude by a contractor prevented removing safety relief valves prior to installing main steam line plugs and possibly resulting in the loss of RCS inventory. The inspectors requested assistance from regional specialists to review the licensees 10 CFR 50.59 evaluation and procedure change. This issue is considered to be an Unresolved Item (URI 05000461/2010002-06, Questions Regarding 10 CFR 50.59 Evaluation for CPS Procedure 3711.01 Involving Operations with the Potential to Drain the Reactor Vessel) pending additional review. The licensee wrote AR 01051306 to address the inspectors questions through its corrective action program |
| Site: | Clinton  |
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| Report | IR 05000461/2010002 Section 1R13 |
| Date counted | Mar 31, 2010 (2010Q1) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.13 |
| Inspectors (proximate) | M Holmberg R Jickling R Langstaff J Cassidy B Metrow B Kemker M Ring S Mischke D Lords E Coffman J Draper A Scarbeary D Sandb Kemker D Lords D Melendez_Colon E Coffman J Cassidy M Mitchell M Ring R Russell S Mischkea Scarbeary B Kemker D Lords J Bozga M Mitchell M Ring S Mischke |
| INPO aspect | |
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Finding - Clinton - IR 05000461/2010002 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Clinton) @ 2010Q1
Self-Identified List (Clinton)
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