ML20209G583
| ML20209G583 | |
| Person / Time | |
|---|---|
| Site: | Paducah Gaseous Diffusion Plant |
| Issue date: | 07/09/1999 |
| From: | Pulley H UNITED STATES ENRICHMENT CORP. (USEC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GDP-99-1019, NUDOCS 9907190200 | |
| Download: ML20209G583 (5) | |
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USEC A Global Energy Company July 9,1999
~ GDP 99-1019
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United States Nuclear Regulatory Commission Attention: Document Control Desk.
Washington, D.C. 20555-0001 Paducah Gaseous Diffusion Plant (PGDP)
Docket No. 70-7001 Event Report ER-99 Pursuant to 10CFR76.120(d)(2), cnclosed is the required 30-day written event report pertaining to the loss'of power to the Criticality Accident Alarm System (CAAS) in Buildings C-409 and C-720-M. The Nuclear Regulatory Commission Headquarters (NRC-HQ) operations office was notified of the event on June 12,1999 (NRC No. 35816). 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, t
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bw ey General Manager Paducah Gaseous Diffusion Plant 4
Enclosures:
As Stated cc: NRC Region III Office
\\j NRC Resident Inspector - PGDP h
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EO. Box 1410, Paducah, KY 42001 Telephone 502-441-5803 Fax 502-441-5801 http://www.usec.com Offices in Livermore, CA Paducah, KY Portsmouth, OH Washington, DC i
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Docket 70-7001 GDP 99-1019 Page1of3 4
EVENT REPORT ER-99-09
- DESCRIPTION OF EVENT '
ion June 10,1999, atlapproximately 1633 hrs., during maintenance activity on the Criticality
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L Accident ' Alarm System (CAAS) in Building C-400, an electrical circuit breaker (LP-B1-E) was opened, resulting in a system trouble alarm on the Building C-409_"AE" CAAS cluster being received in the Central Control Room in C-300. The. Technical Safety Requirement (TSR) for
. Limiting-Conditions For Operations (LCO) were implemented for. Building C-409.
At approximately 2345 hrs., after completion of the Building C-400 maintenance activity, the Plant
. Shift Superintendent (PSS) declared the CAAS system operable. The operability decision was made after the PSS~ determined that the Building C-409 "P" CAAS cluster remained operational;
. thereby, providing total coverage for the building. Additionally, the CAAS horns in Building C-720-M, uninterrupted power source (UPS), has a battery back up. On June 12, 1999, the PSS conducted a review of the Building C-400 CAAS maintenance activity, and determined that the control power for the CAAS building horns in Buildings C-409 and C-720-M were lost on June 10, 1999, for approximately four hours during the maintenance evolution. CAAS detectability and
' ' local horn operability were not affected by the loss of control power. On June 12,1999, at 0510 hrs., the Nuclear Regulatory Commission Headquarters (NRC-HQ) operations office was notified
' of the' event in accordance' with 10CFR76.120(c)(2) (NRC No. 35816).
L On June 10,1999, Maintenance replaced the Building C-400 CAAS beacons located on the exterior of the building according to an approved maintenance work package (R 9813649-02). Prior to the start of work, Operations personnel conducted a review of Engineering Notice (EN) EN-C-833 001, Rev. 2, "CAAS Horns And Lights" which contained sketches identifying power sources for CAAS homs and lights in various buildings,' including Building C-400. Based on a review of the EN it was determined that opening the Building C-400 electrical circuit breaker would not affect CAAS operability in other buildings.. The Building C-400 electrical circuit breaker had labels afYixed to indicate the breaker' was the power source for the building CAAS horns and lights.
(There were no indications in the EN that opening the breaker would affect the CAAS in C-409 and i
C-720-M.
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' The EN was published as a result of a regulatory commitment contained in Event Report ER-98-21 (NRC No. 35060).. The commitm'ent required an Engineering walkdown to identify each electrical breaker in appropriate buildings that supply power to the CAAS back to the point of redundancy.
, The' breakers identified in the EN were appropriately labeled and both commitments have been completed and closed.
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Docket 70-7001 GDP 99-1019 Page 2 of 3 I
LThe PSS, while cond'ucting an evaluation of this event, determined that boundary definition manual
- (BDM)Ldrawing (E5E-19105-A06) contained errors and omissions.. Additionally, there is
' insufficient detail in the drawing to fully understand the electrical system. This deficiency will be i
addressed in planned corrective action 1..
The safety significance of this event was the loss of' power to the CAAS building horns in Building C-409 and C-720-M for approximately!four hours; however, CAAS detectability and local horn and building warning beacons remained operational.
CAUSE FOR'THE EVENT A.' Direct Cause '
The direct cause for this event was opening an electrical circuit breaker, resulting in the loss of power to the CAAS building horns in Buildings C-409 and C-720-M.
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B. Root Cause
. The root cause for this event was a failure of an EN to identify the impact of opening the C-400 electrical breaker on the CAAS building horns in Buildings C-409 and C-720-M. This failure led to the lack of adequate labeling of C-400 breaker (LP-B1-E).
CORRECTIVE ACTIONS.
A. Completed Corrective Actions
- 1. On June 14,1999,; Operations published an Operations Functional Directive (OP-99-001, Rev.1). The directive reemphasizes the responsibility of both the person who operates and who authorizes operation of a breaker to have reasonable assurance of the downstream systems which will be affected and/or to ensure appropriate compensatory measures are -
implemented. - Additionally, this directive emphasizes that CAAS maintenance activities, other than cluster replacements, shall have an Operations Impact Assessment (OIA) completed according to CP3-CO-C01029, " Operations Integration With The Work Control Process" and the OIA'shall be reviewed by the CAAS System Engineer before work-start approval.
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l Docket 70-7001 GDP 99-1019 Page 3 of 3
- 2. On June 14,1999, a caution tag was placed on electrical circuit breaker LP-B1-E indicating that the breaker provides control power to the CAAS building horns in Buildings C-409 and C-720-M.-
l 3.) On June 30,1999, Engineering Notice EN-C-833-99-001, Rev. 2, was placed on hold.
' B; Planned Corrective Actions
~ 1. By January 12, 2000,' Engineering, in conjunction with Operations, Maintenance, and Production Support will complete a walkdown to identify each electrical breaker supplying power to CAAS horns and lights, including those slaved to other buildings. The results of the walkdown will.be documented.~ Individual assessment tracking reports will be issued where an electrical drawing discrepancy is found.
2.~ ' By May 12,2000, Operations, Maintenance and Production Support, will label all breakers within their respective facilities identified in corrective action 1.
- 3. By May 15, 2000, Operations will document the technical information supplied in corrective action number 1 in 'an appropriate procedure or other controlled medium.
EXTENT OF EXPOSURE OF INDIVIDUALS TO RADIATION OR RADIOACTIVE a
MATERIAL
. None LESSONS LEARNED -
L Adequate labeling of electrical breakers, and understanding the impact of breaker manipulation, is necessary prior to opening a breaker that could impact a safety system.
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Docket 70-7001 GDP 99-1019 Page1of1 List of Commitments Event Report ER-99 1.
By. January 12, 2000, Engineering,-in conjunction with Operations,. Maintenance, and Production Support will complete a walkdown to identify-each electrical breaker supplying power to CA AS horns and lights, including those slaved to other buildings / The results of the walkdown will be documented. Individual assessment tracking reports will be issued where an
. electrical drawing discrepancy is found.
- 2. By May 12,-2000, Operations, Maintenance and Production Support, will label all breakers within their respective facilities identified in corrective action 1.
- 3. By May 15,2000,' Operations will document the technical information supplied in corrective action number 1 in an appropriate procedure or other controlled medium.
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