05000461/LER-2010-004
| Docket Number | |
| Event date: | 01-17-2010 |
|---|---|
| Report date: | 01-25-2011 |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4612010004R00 - NRC Website | |
PLANT AND SYSTEM IDENTIFICATION
General Electric — Boiling Water Reactor, 3473 Megawatts Thermal Rated Core Power Energy Industry Identification System (EllS) codes are identified in the text as [XX].
EVENT IDENTIFICATION
OPDRV Requirements Not Met During Control Rod Drive Mechanism Replacements
A. CONDITION PRIOR TO EVENT
� Unit: 1� Event Date: January 17, 2010 Event Time: 1929 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.339845e-4 months <br /> CST �Reactor Mode: 5� Mode Name: Refueling Power Level: 000 percent � Reactor Coolant Temperature: 79.5 F Reactor Coolant Pressure: Atmospheric
B. DESCRIPTION OF EVENT
On 8/3/10, the Nuclear Regulatory Commission (NRC) issued Non-Cited Violation (NCV) 2010003-02 for a violation of 10 CFR 50.59, "Changes, Tests and Experiments," due to the failure of the Clinton Power Station (CPS) to perform an adequate 10 CFR 50.59 evaluation and obtain a license amendment prior to implementing procedure CPS 3711.01, "CPS Operations with the Potential to Drain the Reactor Vessel (OPDRV)," Revision 0. In the procedure, the station provided limitations which the NRC considered to be a change in the plain language definition of the term OPDRV that, in effect, constituted a change to the Technical Specifications (TS), which would thus require a license amendment pursuant to 10 CFR 50.59(c)(1)(i) and 10 CFR 50.90. An OPDRV is a term not specifically defined in the CPS TS, however the term is used in the TS to define a mode or other specified condition when a TS is applicable. The term OPDRV was meant to be a plain language definition and nothing more, and is intended to address the threat of any reactor coolant inventory loss. The NRC concluded that procedure CPS 3711.01 created a new TS definition of OPDRV by defining a specific threshold below which OPDRV does not apply. The TS wording does not contain a threshold below which OPDRV does not apply; therefore, by defining such a threshold, procedure CPS 3711.01 changes the TS definition. The station suspended procedure CPS 3711.01 from use on 7/13/10.
On 9/1/10, CPS responded to the NCV by submitting a letter to the NRC contesting the NRC NCV. The NRC completed their review of the contest letter and concluded in their letter dated 11/29/10 that the NCV was valid and implementation of procedure CPS 3711.01 involved a change to the TS that required prior approval of the NRC.
During review of the NRC letter on 12/20/10, the station noted that a potentially reportable condition may have occurred during the last refueling outage (C1R12) as procedure CPS 3711.01 was implemented for Control Rod Drive [AA] Mechanism (CRDM) [DRIV] replacement activities in that outage, and TS requirements may not have been met based on the guidance in the OPDRVs procedure and considering the NRC NCV. The station initiated Issue Report 1154358 to determine if TSs were met considering the plain language definition of OPDRV.
The reportability evaluation concluded that procedure CPS 3711.01 was utilized during replacement of CRDMs and resulted in the station not being in compliance with the Technical Specifications required for OPDRVs during the timeframe from 1/17/10 at 1929 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.339845e-4 months <br /> to 1/18/10 at 0511 hours0.00591 days <br />0.142 hours <br />8.449074e-4 weeks <br />1.944355e-4 months <br />.
The following TS and actions applicable during OPDRVs were not met as the CRDM replacement work was not immediately suspended as required by the actions in the limiting conditions for operations (LC0s).
LCO 3.3.6.1 states that the primary containment and drywell isolation instrumentation for each Function in Table 3.3.6.1-1 shall be OPERABLE. With required instrumentation channels not operable, the Required Action is to isolate the affected penetration or initiate action to suspend OPDRVs immediately. This LCO was not met for the leak detection function with both divisions of Reactor Water Cleanup [CE] isolation bypassed.
LCO 3.6.1.2 states that each primary containment air lock [AL] shall be OPERABLE. With any primary containment air lock inoperable during movement of recently irradiated fuel assemblies in the primary or secondary containment, or during OPDRVs, the Required Action is to initiate action to suspend OPDRVs immediately. This LCO was not met with the upper containment airlock not operable.
LCO 3.6.4.1 states that the secondary containment shall be OPERABLE. With secondary containment inoperable during OPDRVs, the Required Action is to initiate action to suspend OPDRVs immediately. This LCO was not met with the railway inner door [DR] not in an operable condition.
Since LCO 3.3.6.1 and LCO 3.6.1.2 were not met, the requirements of LCO 3.0.4 were also not met. LCO 3.0.4 requires the LCO (namely LCO 3.3.6.1 and LCO 3.6.1.2) to be met prior to entry into the MODE or other specified condition (namely the OPDRV activity).
Other activities that used Procedure CPS 3711.01 during refueling outage C1R12 were draining of the Reactor Recirculation [AD] piping loops and Reactor Water Cleanup [CE] piping replacement. Both of these activities were evaluated as not being OPDRV, and this evaluation was consistent with previous plant decisions prior to the existence of Procedure 3711.01.
C. CAUSE OF EVENT
The cause for this event was the 10 CFR 50.59 evaluation concluded that the change did not require prior NRC approval. The station did not use conservative decision-making before proceeding with implementation of the OPDRV procedure.
D. SAFETY CONSEQUENCES
This event is reportable under the provisions of 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by the station TSs as certain TSs were not met as discussed in the Description of Event Section of this report. During the less than 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of CRDM replacement activities from 1929 hours0.0223 days <br />0.536 hours <br />0.00319 weeks <br />7.339845e-4 months <br /> on 1/17/10 to 0511 hours0.00591 days <br />0.142 hours <br />8.449074e-4 weeks <br />1.944355e-4 months <br /> on 1/18/10, the reactor cavity was flooded with at least 22 feet 8 inches of water above the Reactor Pressure Vessel [RPV] flange and two trains (B and C) of Residual Heat Removal [BO], and the Low Pressure Core Spray [BM] systems were available to maintain water level in the event a CRDM opening was not secured. Therefore, this event had minimal safety significance.
E. CORRECTIVE ACTIONS
Station procedure CPS 3711.01, as well as Exelon Standard Procedure OP-AB-117-101, "Operations with the Potential to Drain the Reactor Vessel (OPDRV)," were suspended from use on 7/13/10 and 12/27/10, respectively.
10 CFR 50.59 evaluation CL-2010-E-001 that reviewed procedure CPS 3711.01 will be revised to show that NRC review and approval is required for implementing the procedure.
The details of this event will be presented during 10 CFR 50.59 requalification classes and to applicable personnel who do not have 10 CFR 50.59 qualifications.
F. PREVIOUS OCCURRENCES
None
G. COMPONENT FAILURE DATA
None