ENS 40837
ENS Event | |
|---|---|
21:00 Jun 23, 2004 | |
| Title | Unanalyzed Condition Related to Fire Protection Cable Separation |
| Event Description | This is being reported under 50.72(b)(3)(ii) - Unanalyzed Condition, 50.72(b)(3)(v) - event or condition that could have prevented fulfillment of a safety function, and Catawba License Condition 2F - violation of License Condition 2.C.5 - Fire Protection Program. This report applies to Catawba Unit 2.
On 6/23/04 an original design deficiency related to fire protection cable separation criteria was discovered. The condition relates to a postulated fire in the 'A' Train 4160 Volt Essential Bus switchgear room (ETA). The 'A' and 'B' Train Volume Control tank (VCT) outlet valves are in series providing the normal suction source for the centrifugal charging pumps (standard Westinghouse design). Cables related to the 'A' Train Volume Control Tank outlet valve are in the same fire area as the switchgear for the 'A' Train centrifugal charging pump. Therefore, if a hot short closes the VCT outlet valve, with the 'B' pump running, both centrifugal charging pumps could be rendered inoperable. Additional switchgear related to component cooling, and power cables for our Standby Shutdown Facility (backup reactor coolant pump seal cooling), are also located in this fire area. An all consuming fire scenario in ETA Switchgear Room could cause a temporary loss of seal cooling to at least 2 of 4 reactor coolant pumps. The actual distance between the ETA switchgear and SSF cables is approximately 20 ft; therefore the probability of an actual fire resulting in a loss of seal cooling is very low. The unanalyzed condition only exists when the 'B' centrifugal charging pump is in operation (both units currently have 'A' centrifugal charging pump in operation). This situation is analogous to a degraded fire rated assembly such that an all consuming fire in one area would affect multiple trains of safe shutdown equipment. Per our Fire Protection Program we are establishing appropriate fire watches as a remedial action until the issue is resolved. Catawba is currently evaluating if a similar concern exists on Unit 1. A follow-up report will be issued if necessary. The licensee will notify the applicable counties and states and has notified the NRC Resident Inspector.
On 6/23/04 an original design deficiency related to fire protection cable separation criteria for Unit 2 was discovered. The report stated that Catawba was evaluating if a similar concern existed on Unit 1 and that a follow-up report would be issued if necessary. A similar but slightly different condition exists on Unit 1. For Unit 1 the Standby Shutdown Facility (backup seal cooling) cables go through the Train "B" 4160 Essential Switchgear Room (1ETB) rather than 2ETA on Unit 2. This means that for Unit 1, an all consuming fire scenario in 1ETB Switchgear Room could cause a temporary loss of seal cooling. This situation is analogous to a degraded fire rated assembly such that an all consuming fire in one area would affect multiple trains of safe shutdown equipment. Per our Fire Protection Program we are establishing appropriate fire watches as a remedial action until the issue is resolved. Notified R2DO (Haag) |
| Where | |
|---|---|
Catawba  South Carolina (NRC Region 2) | |
| Reporting | |
| 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor | |
| Time - Person (Reporting Time:+-1.4 h-0.0583 days <br />-0.00833 weeks <br />-0.00192 months <br />) | |
| Opened: | Jimmy Burgess 19:36 Jun 23, 2004 |
| NRC Officer: | Arlon Costa |
| Last Updated: | Jun 24, 2004 |
| 40837 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |