05000346/FIN-2009005-07
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Finding | |
|---|---|
| Title | Licensee-Identified Violation |
| Description | On December 16, 2009, the licensee identified that secondary heat balance temperature input, T476, was indicating approximately 8 degrees lower than expected. T476 measures steam temperature at the inlet to the high-pressure turbine from steam generator 2. This temperature is input into the secondary heat balance calculation which is used to calculate reactor power. The licensee calculated that the lower temperature indicated from T476 produced the indicated reactor power level to be approximately 0.27 percent lower than actual power level. Davis-Besse Nuclear Power Station Operating License NPF-3, license condition 2.C.(1), authorizes the facility to be operated at steady state reactor power levels not in excess of 2817 megawatts thermal (100 percent reactor power). Contrary to this, the licensee had operated the facility at steady state full power levels of up to approximately 100.27 percent reactor power since April 2006. Upon discovery, the licensee immediately reduced reactor power and maintained it at 99.5 percent. The temperature detector, T476, was replaced on December 19, 2009, which restored functionality to the secondary heat balance calculation. The issue was entered into the CAP as CR 09-69162. The issue is of very low safety significance because it only involved the potential to affect the fuel cladding barrier and did not affect the reactor coolant system or containment barriers. |
| Site: | Davis Besse  |
|---|---|
| Report | IR 05000346/2009005 Section 4OA7 |
| Date counted | Dec 31, 2009 (2009Q4) |
| Type: | NCV: Green |
| cornerstone | Mitigating Systems |
| Identified by: | Licensee-identified |
| Inspection Procedure: | |
| Inspectors (proximate) | J Rutkowski A Wilson F Mccreesh R Russell J Cameron |
| INPO aspect | |
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Finding - Davis Besse - IR 05000346/2009005 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Davis Besse) @ 2009Q4
Self-Identified List (Davis Besse)
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