ML20046D377
| ML20046D377 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 08/13/1993 |
| From: | Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Delgeorge L CENTERIOR ENERGY |
| Shared Package | |
| ML20046D378 | List: |
| References | |
| NUDOCS 9308190062 | |
| Download: ML20046D377 (3) | |
See also: IR 05000254/1993017
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August 13, 1993
Docket No. 50-254
Docket No. 50-265
Commonwealth Edison Company
ATTN: Mr. L. O. DelGeorge
Vice President, Nuclear
Oversight and Regulatory
Services
Executive Towers West III
1400 Opus Place - Suite 300
Downers Grove, IL 60515
Dear Mr. DelGeorge:
The enclosed report refers to a special inspection conducted by a Region III
special inspection team on June 9 through August 12, 1993, relative to the
Unit 1 High Pressure Coolant Injection (HPCI) system rupture disc burst event.
The team was composed of Messrs. C. Vanderniet, J. Guzman, P. Prescott, and C.
Zelig of this office. An interim inspection exit meeting was held on June 24;
1993, to discuss our findings with Mr. H. Hentschel and others of your staff.
The report also refers to followup activities of your staff and to the
discussion of our findings with Mr. M. Wallace and his staff on July 9,1993.
The final exit on the inspection was held on August 12, 1993 with Mr. R.
Pleniewicz and his sti. 'f via telephone.
Areas examined during the special inspection are identified in the report.
Within these areas, the inspection consisted of a selected examination of
procedures, and representative records, observations and interviews with
personnel.
The purpose of the inspection was to determine whether activities
authorized by the license were conducted safely and in accordance with NRC
requirements.
The event resulted from a burst of the Unit 1 HPCI turbine exhaust rupture
discs, filling the HPCI room with steam. These discs had been in service for
over 20 years and were not in the preventive maintenance schedule. The
rupture is believed to have been caused by a gaseous overpressurization of the
discs. The overpressurization resulted from a pressure surge driven by a
water slug expelled from the turbine during startup.
The exact pressure
reached during the event was undetermined.
It is possible that the discs
ruptured prematurely due to age or service related degradation. The water
slug was caused by condensGe that accumulated in the turbine due to a turbine
drain system failure.
The pressure surge in the Unit 1 HPCI room, as a result
of the blown rupture discs, also blew the fire doors separating Units 1 and 2
HPCI rooms off their hinges and blew open both sets of secondary containment
doors leading from the Unit 1 HPCI room.
Inspection by the team of the Units
1 and 2 HPCI rooms noted no further significant damage to the rooms or the
Unit 2 HPCI system.
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August 13, 1993
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A release of slightly radioactive steam, well below regulatory limits,
occurred during the event and was confined to the facility. During the event,
five radiological workers were slightly contaminated and injured by the' steam.
All individuals were decontaminated and one required hospitalization. The
event, however, posed no threat to the general public's health or safety.
Response to the event required HPCI system isolation and treatment,
evacuation, and transportation of injured personnel. The reactor was isolated
from the affected equipment and continued to operate in a stable condition.
The inspection team identified a lack of testing controls, a non-aggressive
,
corrective action program, and inexperienced system engineers as significant
contributors to the event. Drain line level switches were also found to be
degraded in the Unit 2 HPCI and Unit 2 reactor core isolation cooling (RCIC)
systems making them susceptible to similar failures. Additionally, the
materiel and housekeeping conditions in the HPCI and RCIC rooms were found to
be poor as evidenced by materiel deficiencies, accumulation of debris, lack of
cleanliness, and standing water in these areas.
Two apparent violations were identified. These violations are being
considered for escalated enforcement in accordance with the " General Statement
of Policy and Procedure for NRC Enforcement Actions" (Enforcement Policy),10 CFR Part 2, Appendix C.
The first involves inadequate test controls while
conducting the HPCI quarterly pump testing. The second relates to a failure
to take corrective actions for deficiencies in the HPCI system inlet and
turbine drain level switches. Accordingly, no Notice of Violation is
presently being issued for these inspection findings.
Please be advised that
the number and characterization of apparent violations described in the
,
enclosed inspection report may change as a result of further NRC review.
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In accordance with 10 CFR 2.790 of the Commission's regulations, a copy of
this letter and the enclosed inspection report will be placed in the NRC
Public Document Room.
We will gladly discuss any questions you have concerning this inspection.
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Sincerely,
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T. O. Martin, Acting Director
Division of Reactor Safety
Enclosure: Inspection Reports
No. 50-254/93017(DRS);
No. 50-265/93017(DRS)
See Attached Distribution:
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Commonwealth Edison Company
3
August 13, 1993
Distribution:
cc. w/ enclosure:
M. Wallace, Vice President, Chief
Nuclear Officer
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R. Pleniewicz, Site Vice President
R. Bax, Station Manager
A. Misak, Regulatory Assurance
Supervisor
D. Farrar, Nuclear Regulatory
Services Manager
OC/LTDCB
Resident Inspectors - Dresden,
-LaSalle, Quad Cities
Richard Hubbard
J. W. McCaffrey, Chief, Public
Utilities Division
Robert Newmann, Office of Public
Counsel, State of Illinois Center
E. Imbro, NRR
C. Patel, LPM, NRR
State Liaison Officer
Chairman,' Illinois Commerce
Commission
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