05000446/LER-2003-002
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| Reporting criterion: | 10 CFR 50.73(a)(2)(iv)(A), System Actuation |
| 4462003002R00 - NRC Website | |
(2) Verbal miscommunication during shift turnover. The oncoming shift understood from turnover that flow had been established through FW Heaters 5B and 6B by the previous shift, but the string subsequently isolated again on a FW Heater 613 Hi-Hi level indication. The previous shift had in fact only established flow through FW Heaters 5A and 6A and had not attempted to place FW Heaters 513 and 6B in service due to the FW Heater 68 Hi-Hi level indication. This misunderstanding led oncoming shift personnel involved in the event to believe that the "B" string heaters were water solid and therefore, in their judgment, a fill and vent evolution prior to unisolating the string was not required.
(3) Required procedures were not used. Procedure IPO-003B "Power Operations," step 5.4.34 states : "IF 2-HS-2611/12, FW HTR 5A & 6A/5B & 6B BYP VLV is OPEN, THEN restore 516 Heaters to service per SOP-303B." Procedure SOP-303B "Condensate System" includes provisions for filling/venting a feedwater heater string prior to returning it to service. For this event, procedure IPO-003B was being directly referenced as appropriate. Once the FW Heater 6B Hi-Hi level indication light extinguished, isolated FW Heaters 5B and 613 were returned to service without the use of procedure SOP-303B and without first filling/venting the heater string. Restoration of this heater string without reference to any procedure violated ODA-407 "Guideline on Use of Procedures.
V. CORRECTIVE ACTIONS
Immediate corrective actions taken for this event include:
1. Filled and vented feedwater heaters 513 and 6B in accordance with the provisions of SOP-303B "Condensate System.
2. Pressurized feedwater heaters 5B and 6B in accordance with SOP-30313 to verify no excessive leakage present. No excessive leakage was identified.
3. Performed a Condensate System walkdown for possible water hammer effects.
No system damage was identified.
Actions to prevent recurrence of this event, as included in the CPSES Corrective Action Program, are as follows:
1. A post-job critique has been documented and a Lessons Learned memorandum has been issued.
2. Procedures associated with this event have been revised to ensure that procedures are directly referenced during component manipulations.
3. Management expectations for procedure use, ODA-407, "Guideline on Use of Procedures," and how to handle in-process evolutions at shift turnover are being re-enforced.
TXU Energy is considering other corrective actions, including revising appropriate Nuclear Training Lesson Notes and enhancing Licensed Operator simulator training to further emphasize removing/restoring feedwater heaters ft-omit° service and to provide reference to previous in-house operating experience.
VL PREVIOUS SIMILAR EVENTS
There was one previous similar event at CPSES which occurred February 4, 1996 (LER 445/96-00343). In this previous event, the feedwater heater string was intentionally being drained for the purpose of reducing hotwell level. This draining evolution resulted in a significant void in the heater.
Tice cause of the 1996 event was lack of procedural guidance for reducing hotwell inventory via draining to the Turbine Building sump such that low pressure feedwater heater strings are properly restored to service (the draining evolution includes the opening of feedwater heater string drain cooler drain valves which allows air to enter the heater strings). Corrective actions included: (a) enhancement to procedures SOP- 303A1B "Condensate System" and IP0-003A/B "Power Operations"; and (b) issuance of a Lessons Learned memorandum "Restoring an Isolated Heater String" within the Operations Department. The Lessons Learned memorandum discussed the need to properly fill and vent feedwater beaters in accordance with SOP-303A1B prior to returning them to service in order to prevent a water hammer event.