05000346/FIN-2015004-02
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | Technical Specification 3.7.11, Control Room Emergency Air Temperature Control System (CREATCS), requires that two CREATCS trains be maintained operable with the unit operating in Modes 1 through 4. While this TS provides actions and allowed outage time for a single inoperable CREATCS train, there are no provisions for both CREATCS trains being simultaneously inoperable. The provisions of TS LCO 3.0.3, therefore, apply when both CREATCS trains are inoperable at the same time, and require that actions be initiated within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> from the onset of the condition to: Be in Mode 3 within 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />; Be in Mode 4 within 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />; and Be in Mode 5 within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />. As discussed in Section 4OA3.2 of this report, contrary to the requirements of TS 3.7.11, both trains of CREATCS were inoperable for a period of approximately 89 hours0.00103 days <br />0.0247 hours <br />1.471561e-4 weeks <br />3.38645e-5 months <br /> on June 26, 2015, with the licensee taking no actions to place the unit into a Mode required by TS LCO 3.0.3. A licensee causal evaluation concluded that with CREATCS Train No. 1 already inoperable for planned maintenance, CREATCS Train No. 2 was rendered inoperable by the inadvertent opening/bumping of the supply breaker for MOV SW1395, the SW Loop No. 2 Nonessential Isolation Valve, by personnel working on planned maintenance for SW Pump No. 1. The objective of the Barrier Integrity Cornerstone of Reactor Safety is to provide reasonable assurance that physical design barriers (fuel cladding, RCS, and containment) protect the public from radionuclide releases caused by accidents or events. A key attribute of this objective involves maintaining the radiological barrier functionality of the plants control room, which is supported by CREATCS. In accordance with NRC IMC 0612, Power Reactor Inspection Reports, Appendix B, Issue Screening, the inspectors determined that the violation was of more than minor significance in that it had a direct impact on this cornerstone objective. Specifically, two independent and redundant trains of the CREATCS are required to be operable to ensure that at least one is available, assuming a single failure disables the other train. The loss of both CREATCS trains could result in equipment within the control room exceeding operational temperature limits in the event of an accident. Using NRC IMC 0609, Appendix A, The Significance Determination Process for Findings At-Power, Exhibit 3, Barrier Integrity Screening Questions, the inspectors determined that the violation was of very low safety significance (Green). Specifically, while the issue was not exclusively limited to the degradation of the radiological barrier function provided for the control room, it did not also simultaneously represent a degradation of the barrier function of the control room against smoke or a toxic atmosphere. As discussed in Section 4OA3.2 of this report, the licensee had entered this issue into their CAP as CR 201508774. Licensee corrective actions included the planned installation of protective covers over critical circuit breakers located on motor-control centers in the SW pump room. |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2015004 Section 4OA7 |
| Date counted | Dec 31, 2015 (2015Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | B Kemker D Kimble I Hafeez J Cameron J Rutkowski J Wojewoda M Bielby M Garza M Jeffers M Marshfield S Bell T Briley |
| Violation of: | Technical Specification |
| INPO aspect | |
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Finding - Davis Besse - IR 05000346/2015004 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2015Q4
Self-Identified List (Davis Besse)
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