ML20206N926
| ML20206N926 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 12/18/1998 |
| From: | Pulley H UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-98-1078, NUDOCS 9812240084 | |
| Download: ML20206N926 (6) | |
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l CSEC A Global Energy Company
'99 JM1 -7 P1 '30 December 18,1998 i'Uc
.J" GDP 98-1078 -
R United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Docket No. 70-7001
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Event Report' ER-98-29 Pursuant to 10CFR76.120(d)(2), enclosed is the required 30-day written event report covering the interruption of pm er to the Criticality Accident Alarm System (CAAS) beacons, Building C-310.
The Nuclear Regulatory Conunission Headquarters (NRC-HQ) operations office was notified of the event on November 19,1998 (NRC No. 35060). Commitments contained in this submittal are identified in Enclosure 2.
Any questions regarding this matter should be directed to Larry Jackson at (502) 441-6796.
Sincerely, i
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>u, General Manager Paducah Gaseous Diffusion Plant
Enclosure:
As Stated cc: NRC Region ill Office f
NRC Pesident Inspector - PGDP
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9812240084 981218 i-l PDR ADOCK 07007001 C
PDR P.O. Box 1410, Paducah, KY 42001 Telephone 502-441-5803 Fax 502-441-3801 http.//www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth. OH Washington, DC
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Docket No. 70-7001 l
GDP 98-1078 j
Page1of4 EVENT REPORT ER-98-29 DESCRIPTION OF EVENT On November 19,1998, at approximately 1245 hrs., while attempting to place cell 5, Building C-310 on-stream, the BB2 electrical breaker would not close. To replace the BB2 electrical breaker, power was removed to the cell 5 valve control center (A-3-5V). The First-Line Manager (FLM) manually opened cell 5 control center main breaker resulting in loss of power to the 120 VAC line recorder distribution panel that feeds the Criticality Accident Alarm System (CAAS) in Building C-310 causing the CAAS beacon lights to become inoperable. The CAAS detectability and audibility capability was not atTected. The. Central Control Facility in Building C-300 received trouble alamis f,or CAAS clusters "G" and "H" in Building C-310, and Building C-310 personnel were notified.
The CAAS is required to be operable under the provisions of Technical Safety Requirements (TSR) 2.3.4.7 and 2.4.4.2. The operators responded according to procedure and, at approximately 1248 hrs., Limiting Conditions For Operation (2.3.4.7b) were initiated. At approximately 1301 hrs.,
power was restored to the CAAS utilizing an altemate source of power. On November 19,1998, at 2253 hrs., the Nuclear Regulatory Commission Headquarters (NRC-HQ) operations office was notified of the event in accordance with 10CFR 76.120(c)(2) (NRC No. 35060).
The FLM was interviewed relative to the event. He stated that at the time of the event while attempting to put cell 5 on-stream, the BB2 electrical breaker would not close. The BB2 electrical breaker providu power to a cell 5 motor operated valve (MOV). In preparation for replacing the BB2 electrical breaker, the FLM removed power to the valve control center. By opening the control center main breaker, power to the CAAS beacon lights was interrupted for approximately 16 minutes causing the CAAS beacon lights to become inoperable. The FLM stated that the cell 5 valve control center breaker feeding the line recorder distribution panel was labeled " analytical equipment transformer"; however, there are no labels or tags indicating that opening the breaker would render the CAAS beacon lights inoperable. Additionally, the FLM stated that he was unaware of the availability of a manually operated electrical throwover switch that could have transferred the CAAS power supply from cell 5 to cell 10 prior to opening the control center main breaker. If the throwover switch had been operated this event would not have occurred.
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1 Docket No. 70-7001 GDP 98-1078 Page 2 of 4 l
The FLM stated that two days earlier (November 17,1998) BB2 electrical breakers were changed on cell 7 and cell 8 without encountering power interruptions. The lack of difficulty in this latter operation can be attributed to the existence of an automatic throwover switch (versus a manual throwover on cell 5) that transferred power prior to opening the control center main breaker and to the existence of properly labeled breakers.
The safety significance of this event is considered low for the following reasons: 1) The short duration of the power interruption to the CAAS beacon lights (16 minutes); 2) plant personnel were aware of the loss of operability of the CAAS beacon lights; 3) immediate corrective actions were initiated; 4) the power interruption did not effect the CAAS detectability and audibility capabilities.
The FLM did not meet management's expectations, or the intent of procedure UE2-OP-OP1030,
" Conduct of Operations," when he opened the cell 5 control center main breaker labeled " analytical equipment transformer" without fully understanding the potential impact of manipulating the breaker. Furthermore, the FLM did not meet management's expectations when he opened the breaker, in that such an action is restricted to qualified operators trained to perform such activities, per CP2-CO-C01032," Shift Routines and Operating Practices."
CAUSE OF THE EVENT A. Direct cause The direct cause of this event was the interruption of electrical power to the CAAS beacons in Building C-310, caused by opening the control center main breaker.
B. Root Cause The root cause for this event was less than adequate knowledge of management's " conduct of" expectations. This contributed to the FLM's manipulation of the control center main breaker without adequate training. Manipulating equipment, including electrical breakers, is performed by trained, qualified operators. FLMs may not always be qualified to manipulate breakers, as in the case of this event.
C. Contributing Cause A contributing cause for this event was an absence oflabels affixed to the breaker, indicating that opening the breaker would result'in the inoperability of the Building C-310 CAAS beacons.
t Properly labeled breakers may have precluded this event.
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Docket No. 70-7001 GDP 98-1078 Page 3 of 4 l
CORRECTIVE ACTIONS i
A. Completed Corrective Actions
- 1. On November 19,1998, caution tags were hung on the main breakers for cell 5 and cell 10 control centers stating that the breakers supply power to the CAAS beacons.
- 2. On November 20,1998, as a result of a partial loss of plant air due to compressor trips (Event Report ER-98-13, Rev.1; NRC No. 34236), an assessment of the impact and reliability of the plant electrical power supply system was completed. Included in the assessment is a recommendation relevant to this event to identify with a special marking each electrical breaker that provides power to the CAAS and Process Gas Leak Detection (PGLD) systems back to the point of redundancy. Planned corrective actions numbers 1,2,3, and 5 below address identification and labeling of electrical breakers.
- 3. On November 23,1998, Commitment Management published a synopsis of this event in a plant-wide computer media. The synopsis emphasized that this event was the result of human error, and that a questioning attitude might have precluded this event.
- 4. On December 3,1998, a crew briefing for appropriate employees assigned to Operations was completed. The cre'v briefing discussed: absence of labels or tags indicating that cell control centers are sources for CAAS power; the absence of a questioning attitude leading to a breaker being opened without first gaining an understanding as to what equipment could be affected; and, an awareness of the stop, think, act, review (STAR) principle was re-emphasized.
- 5. On December 16, 1998, a Functional Directive was issued clarifying management expectations on manipulation of electrical breakers.
B. Planned Corrective Actions
- 1. By January 15,1999 Engineering will complete a walkdown to identify each electrical breaker in appropriate buildings that supply power to the CAAS systems back to the point l
ofredundancy.
- 2. By May 31,1999, Operations will label all electrical breakers identified in corrective action number 1, abov t l
m, Enclosure i Docket No. 70-7001 GDP 98-1078 Page 4 of 4
- 3. By August 30,1999, Engineering will complete a walkdown to identify each electrical breaker in appropriate buildings that supply power to the PGLD systems back to the point ofredundancy.
- 4. By August 30, 1999, Operations will modify applicable " conduct of" procedure (s) to reinforce and clarify management standards that: a) prior to manipulating equipment or systems, operators are expected to question and understand the anticipated system response l
and impact; and, b) regarding FLMs manipulating equipment or systems.
- 5. By January 31, 2000, Operations will label all electrical breakers identified in corrective action number 3, above.
- 6. By January 31,2000, Operations will document the technical information supplied in actions 1 and 3, above in an appropriate procedure or other controlled medium.
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EXTENT EXPOSURE OF INDIVIDUALS TO RADIATION OR RADIOACTIVE MATERI ALS i
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LESSONS LEARNED l
A questioning attitude prior to this event could have precluded the inoperability of a safety system (CAAS beacons).
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1 Docket No. 70-7001 GDP 98-1078 l
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Event Report ER-98-29 List of Commitments
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- l. By January 15,1999, Engineering will complete a walkdown to identify each electrical breaker in appropriate buildings that supply power to the CAAS systems back to the point of redundancy.
- 2. By MayN31,1999, Operations will label all electrical breakers identified in action number 1, above.
3 By August 30,1999, Operations will modify applicable " conduct of" procedure (s) to reinforce and clarify management standards that: a) prior to manipulating equipment or systems, operators are expected to question and understand the anticipated system response and impact; and, b) regarding FLMs manipulating equipment or systems.
- 4. By January 31,2000, Operations will document the technical information supplied in action number 1, above in an appropriate procedure or other controlled medium.
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- Regulatory commitments contained in this document are listed here. Other corrective actions listed in this submittal are not considered regulatory commitments in that they are either statements of actions completed, or they are considered enhancements to USEC's investigation, procedures, programs, or operations.
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