05000327/FIN-2005011-03: Difference between revisions
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| identified by = NRC | | identified by = NRC | ||
| Inspection procedure = IP 71111.05 | | Inspection procedure = IP 71111.05 | ||
| Inspector = N Merriweather, B Melly, R Schin, D Payne, J Quinones,-Navarrof | | Inspector = N Merriweather, B Melly, R Schin, D Payne, J Quinones, -Navarrof Mccreeshj Montgomery, N Staples, P Fillion, R Nease, R Rodriguez | ||
| CCA = N/A for ROP | | CCA = N/A for ROP | ||
| INPO aspect = | | INPO aspect = | ||
| description = The team identified an URI related to the design of the sprinkler system in the cable spreading room, in that, the sprinklers were apparently installed too far below the ceiling. This issue is unresolved pending further NRC review of the licensing basis and the suppression capability of the installed sprinkler system. The team observed that all of the installed sprinklers in the cable spreading room were 30 inches or more below the ceiling. However, the NFPA code requires that sprinklers be installed within 18 inches of the ceiling. Positioning the sprinklers farther below the ceiling results in a delayed sprinkler response and allows a fire to grow larger in size. The Sequoyah FPP stated that sprinkler systems comply with the NFPA Code for installation of sprinkler systems. The SQN Fire Protection Report, Part VII - Deviations and Evaluations, paragraph 5.1.1, stated that sprinkler systems comply with NFPA 13- 1975, with certain exceptions. The list of exceptions did not include any sprinklers being installed farther below the ceiling than allowed by the NFPA code. NFPA 13-1975, Section 4-3.1, requires that for smooth ceiling construction, deflectors of sprinklers in bays shall be located 1 inch to 12 inches below noncombustible ceilings. For panel construction, the code allows sprinklers to be as much as 18 inches below the ceiling; however, in no case does the code allow sprinklers to be 30 inches below the ceiling. In a Safety Evaluation Report (SER), (NUREG-011, Supplement 1), the NRC approved the licensees sprinkler system design for the cable spreading room, including the use of an upper level near the ceiling and an intermediate level approximately halfway between the floor and the ceiling. However, the NRC SER did not specifically recognize that the upper level of sprinklers was more than 18 inches below the ceiling. The team concluded that the SER did not appear to approve a deviation from the NFPA code. In Generic Letter (GL) 86-10, the NRC stated a staff position that licensees may deviate from NFPA code requirements with an evaluation approved by a fire protection engineer. GL 86-10 stated that such deviations from the NFPA code should be identified in the FSAR or FHA. However, GL 86-10 also stated an NRC staff position that sprinkler heads should be located at the ceiling. The team observed that the cable spreading room contained cables for both units and was very large in volume (approximately 219 feet long by 42 feet wide and 25 feet high). Rows of intermediate sprinklers were located between rows of upper sprinklers such that most fires that could start near the floor would generate a wide heat plume that would impact at least one upper or intermediate level sprinkler. The sprinklers had metal heat collectors installed above them; however, NRC Information Notice 2002-024 describes potential problems with such heat collectors. Also, sprinklers that were not directly in the heat plume of a fire could potentially have a significantly delayed response to the fire. This issue remains open for further NRC review of the licensing basis and the suppression capability of the installed sprinkler system. The issue is identified as URI 05000327,328/2005011-03, Sprinklers Apparently Too Far Below Ceiling in Cable Spreading Room. | | description = The team identified an URI related to the design of the sprinkler system in the cable spreading room, in that, the sprinklers were apparently installed too far below the ceiling. This issue is unresolved pending further NRC review of the licensing basis and the suppression capability of the installed sprinkler system. The team observed that all of the installed sprinklers in the cable spreading room were 30 inches or more below the ceiling. However, the NFPA code requires that sprinklers be installed within 18 inches of the ceiling. Positioning the sprinklers farther below the ceiling results in a delayed sprinkler response and allows a fire to grow larger in size. The Sequoyah FPP stated that sprinkler systems comply with the NFPA Code for installation of sprinkler systems. The SQN Fire Protection Report, Part VII - Deviations and Evaluations, paragraph 5.1.1, stated that sprinkler systems comply with NFPA 13- 1975, with certain exceptions. The list of exceptions did not include any sprinklers being installed farther below the ceiling than allowed by the NFPA code. NFPA 13-1975, Section 4-3.1, requires that for smooth ceiling construction, deflectors of sprinklers in bays shall be located 1 inch to 12 inches below noncombustible ceilings. For panel construction, the code allows sprinklers to be as much as 18 inches below the ceiling; however, in no case does the code allow sprinklers to be 30 inches below the ceiling. In a Safety Evaluation Report (SER), (NUREG-011, Supplement 1), the NRC approved the licensees sprinkler system design for the cable spreading room, including the use of an upper level near the ceiling and an intermediate level approximately halfway between the floor and the ceiling. However, the NRC SER did not specifically recognize that the upper level of sprinklers was more than 18 inches below the ceiling. The team concluded that the SER did not appear to approve a deviation from the NFPA code. In Generic Letter (GL) 86-10, the NRC stated a staff position that licensees may deviate from NFPA code requirements with an evaluation approved by a fire protection engineer. GL 86-10 stated that such deviations from the NFPA code should be identified in the FSAR or FHA. However, GL 86-10 also stated an NRC staff position that sprinkler heads should be located at the ceiling. The team observed that the cable spreading room contained cables for both units and was very large in volume (approximately 219 feet long by 42 feet wide and 25 feet high). Rows of intermediate sprinklers were located between rows of upper sprinklers such that most fires that could start near the floor would generate a wide heat plume that would impact at least one upper or intermediate level sprinkler. The sprinklers had metal heat collectors installed above them; however, NRC Information Notice 2002-024 describes potential problems with such heat collectors. Also, sprinklers that were not directly in the heat plume of a fire could potentially have a significantly delayed response to the fire. This issue remains open for further NRC review of the licensing basis and the suppression capability of the installed sprinkler system. The issue is identified as URI 05000327,328/2005011-03, Sprinklers Apparently Too Far Below Ceiling in Cable Spreading Room. | ||
}} | }} | ||
Revision as of 20:31, 20 February 2018
| Site: | Sequoyah  |
|---|---|
| Report | IR 05000327/2005011 Section 1R05 |
| Date counted | Dec 31, 2005 (2005Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.05 |
| Inspectors (proximate) | N Merriweather B Melly R Schin D Payne J Quinones -Navarrof Mccreeshj Montgomery N Staples P Fillion R Nease R Rodriguez |
| INPO aspect | |
| ' | |