05000334/FIN-2015007-02
From kanterella
Jump to navigation
Jump to search
Finding | |
|---|---|
| Title | Unit 1 Control Room HVAC Equipment Room Safe Shutdown Capability Affected by Smoke Migration |
| Description | The team identified a finding of very low safety significance (Green) involving a non-cited violation of 10 CFR 50 Appendix R, III.L.3. for failure to establish an alternative safe shutdown capability independent of the Unit 1 control room HVAC equipment room, sub-fire area CR-2. Specifically, a fire in CR-2 will generate heat and smoke that will rise to the Unit 1 main control room where post-fire safe shutdown equipment is remotely operated in response to a fire in CR-2. This issue was determined to satisfy the criteria specified for the exercise of enforcement discretion for plants in transition to a fire protection program that meets the requirements of 10 CFR 50.48(c), National Fire Protection Association Standard NFPA 805. Description. The team reviewed the Updated Fire Protection Appendix R Report, Rev. 31 for BVPS Unit 1 and noted that Duquesne Light Company filed an exemption request on January 14, 1985, in part for fire area CR-2, from the requirements of 10 CFR 50, Appendix R. The exemption request also redefined CR-2 as a subarea of the main control room fire area, CR-1, based on a ventilation shaft traversing the CR-2 ceiling and CR-1 floor. The exemption request redefined CR-2 and CR-1 as a single alternative shutdown fire area in accordance with Section III.G.3 of Appendix R. The NRC approved the exemption request in a letter dated December 4, 1986. The team noted that Duquesne Light Companys exemption request justified adequate separation for safe shutdown systems and fire suppression and detection within the affected fire area, but did not identify that operators would be required to remain in the main control room to operate safe shutdown equipment for a fire in CR-2. This is unlike the established safe shutdown capability for the main control room where operators would leave the main control room to locally operate safe shutdown equipment. Local operation of safe shutdown equipment ensured equipment and circuits were isolated from the effects of the fire and operators would not be subject to smoke or heat. The team noted that Updated Fire Protection Appendix R Report, Rev. 31 credited safe shutdown equipment for a fire in CR-2 to be operated from the main control room and procedure 1OM-56B.4.C, Safe Shutdown Following A Serious Fire in the Control Building, Rev. 12, specific to fires in CR-2 and CR-3, the relay room, provided operating instructions consistent with the fire safe shutdown analysis. The team additionally noted that the unqualified fire damper in the ventilation shaft between CR-2 and CR-1 can only be operated at a local panel inside CR-2. The team considered that operators remaining in the main control to establish post-fire safe shutdown for a fire in CR-2 was an alternative safe shutdown capability that was not independent of the fire area. In response to the teams concern for smoke and heat rising from CR-2 affecting operator visibility or main control room habitability, FENOC provided calculation, SCI- 17756-03, NFPA 805 Fire PRA Task 11c, Multi Compartment Fire Analysis for BVPS Unit 1, Rev. F. Attachment 3 of this calculation analyzed the potential for propagation of hot gases into the main control room via the non-fire rated ventilation duct shaft. The team determined the analysis was conservative and concluded that operators could remain in the main control room and would have more than one hour to initiate the Unit 2 main control room ventilation system in smoke purge mode. The team judged that procedure 1OM-56B.4.C, Safe Shutdown Following A Serious Fire in the Control Building, Rev. 12, was deficient because it did not provide any caution to control room operators that a fire in CR-2 could generate heat and smoke that could rise to the main control room. Additionally, the procedure did not provide any instructions to remove the heat and smoke such as by placing the Unit 2 main control room ventilation system in smoke purge mode. FENOC promptly entered this safe shutdown issue into their corrective action program (CAP) as CR-2015-10577 and intended to revise 1OM-56B.4.C, Safe Shutdown Following A Serious Fire in the Control Building, to include a note to initiate smoke purge mode of the Unit 2 control room ventilation system as needed for a fire in CR-2. The team considered FENOCs corrective actions appropriate. Analysis. The failure to establish an alternative safe shutdown capability independent of the Unit 1 control room HVAC equipment room, sub-fire area CR-2, is a performance deficiency (PD). This PD is more than minor because it is associated with the external events (fire) attribute of the Mitigating Systems Cornerstone and adversely affected the cornerstone objective of ensuring the availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences. Using IMC 0609, Appendix F, Fire Protection Significance Determination Process, the team determined that this issue screens to Green in task 1.3.1 because the reactor is able to reach and maintain safe shutdown: a conservative calculation determined the main control room operators would not be impaired. Cross-cutting aspects are not applicable to findings involving enforcement discretion. Enforcement. 10 CFR 50.48(b)(2) requires that all nuclear power plants licensed to operate before January 1, 1979, must satisfy the applicable requirements of 10 CFR 50, Appendix R, including specifically the requirements of Sections III.G, III.J, and III.O. 10 CFR Part 50, Appendix R, Section III.G.2 requires, in part, that, where cables or equipment of redundant trains of systems necessary to achieve and maintain hot shutdown conditions are located within the same fire area outside of primary containment, one of the stated means of ensuring that one of the redundant trains is free of fire damage shall be provided. The stated means include separation of cables and equipment and associated non-safety circuits of redundant trains through the use of specified fire barriers, distance, or suppression systems. 10 CFR part 50, Appendix R, Section III.G.3 requires, in part, that alternative or dedicated shutdown capability should be provided where the protection of systems whose function is required for hot shutdown does not satisfy the requirement of paragraph G.2 of this section. 10 CFR Part 50, Appendix R, Section III.L.3, in part, specifies that alternative shutdown capability shall be independent of the specific fire area. Contrary to the above, since December 4, 1986, BVPS Unit 1, a nuclear power plant licensed to operate before January 1, 1979, has not satisfied the applicable requirements of 10 CFR 50, Appendix R, Section III.G, in that the licensee did not provide alternative shutdown capability that was independent of a specific fire area where the protection of systems whose function is required for hot shutdown was not ensured to be free of fire damage. Specifically, for a fire in CR-2, FENOC required operators to remain in the main control room to operate safe shutdown equipment. However, the main control room was not independent of the fire area, since the main control room will be impacted by heat and smoke generated from a fire in CR-2. The violation was historical and occurred when Duquesne Light Company, a predecessor to FENOC, implemented a January 14, 1985, exemption request from the requirements of Appendix R. FENOC is in transition to NFPA 805 and, therefore, this NRC-identified violation was evaluated in accordance with the criteria established in Section 9.1 of the NRC Enforcement Policy, Enforcement Discretion for Certain Fire Protection issues (10 CFR 50.48). Specifically, because all of the criteria were met, the NRC is exercising discretion and not issuing a violation for this issue. |
| Site: | Beaver Valley  |
|---|---|
| Report | IR 05000334/2015007 Section 1R05 |
| Date counted | Sep 30, 2015 (2015Q3) |
| Type: | Violation: Green |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | C Cahill D Orr J Patel J Rady J Rogge S Galbreath |
| Violation of: | 10 CFR 50 Appendix R 10 CFR 50 Appendix R Section III.G 10 CFR 50 Appendix R Section III.L 10 CFR 50.48 |
| INPO aspect | |
| ' | |
Finding - Beaver Valley - IR 05000334/2015007 | |||||||||||||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Finding List (Beaver Valley) @ 2015Q3
| |||||||||||||||||||||||||||||||||||||||||||||||||