05000400/LER-2003-004, Regarding Auxiliary Feedwater Actuation Following Closure of the Reactor Trip Breakers
| ML032300488 | |
| Person / Time | |
|---|---|
| Site: | Harris  |
| Issue date: | 08/12/2003 |
| From: | Waldrep B Progress Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| HNP-03-087 LER 03-004-00 | |
| Download: ML032300488 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| 4002003004R00 - NRC Website | |
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Cj Progress Energy AUG 1 2 2003 U.S. Nuclear Regulatory Commission ATTN: NRC Document Control Desk Washington, DC 20555 Serial: HNP-03-087 10CFR50.73 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NO. 50-400/LICENSE NO. NPF-63 LICENSEE EVENT REPORT 2003-004-00 Ladies and Gentlemen:
The enclosed Licensee Event Report 2003-004-00 is submitted in accordance with 10 CFR 50.73. This report describes an auxiliary feedwater actuation following closure of the reactor trip breakers. Event notification EN 39939 previously reported this event in accordance with 10 CFR 50.72.
Please refer any questions regarding this submittal to Mr. John Caves, Supervisor -
LicensinglRegulatory Programs, at (919) 362-3137.
Sincerely, Plant Generg Manager Harris Nuclear Plant BCW/jpy Enclosure c:
Mr. R. A. Musser (HNP Senior NRC Resident)
Mr. C. P. Patel (NRC-NRR Project Manager)
Mr. L. A. Reyes (NRC Regional Administrator, Region II)
Progress Energy Carolinas, Inc.
Harris Nuclear Plant P.O Box 165 New Hill, NC 27562
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Abstract
On June 15, 2003 at 0928 with the reactor shutdown in Mode 3, an automatic actuation of the auxiliary feedwater (AFW) system occurred following closure of the reactor trip breakers (RTBs) in preparation for a reactor startup. Due to an inappropriate equipment configuration, closing the reactor trip breakers resulted in two of the Main Feedwater Regulating Valves (MFRVs) opening to their full-open position. Water levels in two steam generators increased and exceeded the high-high level setpoint (78%). This condition resulted in a trip of the A" main feedwater pump, which initiated an auto-actuation of both motor-driven auxiliary feedwater (MDAFW) pumps.
The root causes of the event are substandard performance of license duties by both individuals and the control room team. Corrective actions for these events cover a broad spectrum of plant programs and personnel management including training, procedures, and personnel assignment. Immediate corrective action verified that plant components were properly aligned to support plant start-up and adjustment of the control room crew assignments. Additional corrective actions include revising the procedure to verify proper alignment of the MFRVs prior to closure of the RTBs (complete) and enhancing operator training.
NRCU FUM 366 tf-VU )
(If more space Is required, use additional copies of (if more space is required, use additional copies of (if more space Is required, use additional copies of NRC Form 366A)
Ill.
SAFETY SIGNIFICANCE (Continued)
The increase in feedwater flow resulted in a maximum SG level of 82%. The plant is designed for an increase in feedwater flow and responded as expected for this condition. The operations crew responded to the event in accordance with plant procedures. No additional or compensatory measures were required for this event.
No significant safety consequences exist under reasonably expected alternate conditions that would place the plant in a condition beyond its design bases.
IV.
PREVIOUS SIMILAR EVENTS
No previous HNP events or conditions are known related to an improperly aligned MFRV that caused an engineered safety feature (ESF) actuation. One previous condition is known related to lack of control room teamwork, and command and control.
HNP LER 95-010-00 (reported 11/13/95)
At 5% power, a turbine trip - reactor trip occurred during turbine mechanical overspeed testing when an operator mistakenly placed the turbine overspeed protection controller (OPC) switch in the OPC TEST position versus the OVERSPEED TEST PERMISSIVE position. The OPC functioned as designed, causing the turbine governor and intercept valves to begin closing thus reducing turbine speed. After a brief discussion among the control room staff, the senior control operator directed the operator to return the switch to its original position. When the OPC switch was returned to the IN SERVICE position, the turbine control system functioned as designed and immediately attempted to return the turbine from approximately 1690 rpm to 1800 rpm, causing a sudden increase in steam flow to the turbine. This increase in steam flow caused steam generator (SG) levels to increase, subsequently generating a SG high-high level signal on the 13B" SG. This signal resulted in a turbine trip, reactor trip, and main feedwater isolation. The trip of the "B" main feedwater pump generated an auxiliary feedwater (AFW) start signal to both motor-driven AFW pumps.
The cause of the condition was attributed to a lack of operator knowledge on the turbine control panel, and insufficient control room command and control, teamwork, and communications.
Corrective actions included operator counseling, installation of clearer OPC switch markings, refresher teamwork training for the operators, and re-enforcing the use of human error reduction techniques during simulator training.
Since these corrective actions were implemented, no turbine trip - reactor trip has occurred due to mispositioning of the OPC switch.
The previous condition involved an inappropriate recovery during a plant transient caused by a mispositioned OPC switch. With the turbine reducing speed, the control room staff was faced with making time-critical decisions. The current event involved misaligned MFRVs for a significantly longer period of time (approximately one day) with two different control room shifts. Although the previous condition and the current event involve the same root cause (teamwork and command and control), due to the differences in time, processes, personnel, and circumstances, no significant pattern in recurring events has been identified. Therefore, the previous corrective actions would not have prevented the current event.