ML20035G032
| ML20035G032 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 04/15/1993 |
| From: | Davis A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Stratman R CENTERIOR ENERGY, CLEVELAND ELECTRIC ILLUMINATING CO. |
| Shared Package | |
| ML20035G033 | List: |
| References | |
| NUDOCS 9304260049 | |
| Download: ML20035G032 (5) | |
See also: IR 05000440/1993006
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APR 151993
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Docket No. 50-440
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Centerior Service Company
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ATTN: Mr. Robert Stratman
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Vice President
Nuclear - Perry
c/o The Cleveland Electric Illuminating
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Company
10 Center Road
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Perry, OH 44081
Dear Mr. Stratman
The enclosed report refers to a special onsite review by an NRC Augmented
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Inspection Team (AIT) on March 27, 1993, through April 2, 1993, relative to
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the service water pipe break at the Perry Nuclear Power Plant on
March 26, 1993, and the subsequent flooding in some areas in the plant.
The
team was composed of Messrs. R. D. Lanksbury, J. F. Schapker, A. Vegel,- and
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J. G. Guzman of this office; Dr. R. B. Landsman of this office; and
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Mr. G. P. Hornseth of the Office of Nuclear Reactor Regulation (NRR). The
report also refers to the followup activities of your staff and to the
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discussion of our findings with Mr. D. P. Igyarto and others of your staff at
the conclusion of the inspection.
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The enclosed copy of our Augmented Inspection Team report identifies areas
examined during the inspection. Within these areas, the inspection consisted
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of a selective examination of procedures, and representative records,
observations, and interviews with personnel.
The Augmented Inspection Team was formed to gather information on the-event.
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Specifically, the team examined your response to the event, effects of
flooding, root causes of the pipe break, and proposed corrective actions.
It
is not the responsibility of an Augmented Inspection Team to determine
compliance with NRC rules and regulations or to recommend enforcement actions.
These aspects will be reviewed in a subsequent inspection.
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The consequences of the event posed no threat to public health and safety. A
minor gaseous radiological release occurred but was not directly attributable
to the event.
The release was minimal and well below regulatory limits.
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Response to the event required a rapid reactor shut down, including a manual
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reactor scram, and the consequent actuation of safety equipment.
All
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equipment operated as expected during recovery from the event. No significant
operational safety parameters were approached or exceeded.
Internal plant
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flooding was limited and did not reach a level that could affect safety-.
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related equipment.
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The pipe rupture is believed to have resulted from a small perforation and
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leak in the pipe which slowly grew in size due to erosion.
Several potential
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root causes for development of the initial perforation were identified.
However, the failure analysis effort was hampered by the fact that substantial
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APR 151993
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portions of the failed pipe were lost at the time of pipe rupture. As a
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result, a single root cause could not be determined; furthermore, it is
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unlikely that additional investigation will yield an answer.
The team does
believe that the conditions which led to the pipe rupture were localized.
The
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local failure mechanism concept appears to be supported by the absence of
widespread cracking'which would result from excessive bending or other gross
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loads during service.
Inspection of the limited sections of service water
system piping that could be observed by the team indicated that no system wide
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degradation appeared to have occurred.
Your initial recovery from the event was thorough. However, corrective
actions from a similar event in December 1991 had only partiality been
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implemented and, as a result, internal flooding that had occurred previously
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occurred again through the same or similar pathways. At the conclusion of
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this inspection you had not yet completed formulating your corrective actions
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for this event. As a result, the team was unable to review them. We
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understand that you will provide your corrective actions as specified in the
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Confirmatory Action Letter (CAL) dated March 30, 1993. We will continue to
closely follow your repair efforts and other corrective actions that you plan.
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We also understand that you are evaluating the feasability of performing
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periodic inspections of the service water system. We would appreciate you
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addressing this issue in your response to the CAL.
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The team concluded that the operators safely responded in an excellent manner
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to the event and that their actions were indicative of a strong knowledge of
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plant systems and procedures.
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In accordance with 10 CFR 2.790 of the Commission's regulations, a copy of
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this letter and the enclosed inspection report will be placed in the NRC
Public Document Room.
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We will gladly discuss any questions you have concerning this inspection.
Sincerely,
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ORIGINAL SIGNED BY llUELRT J. MILLER
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T<v A. Bert Davis
Regional Administrator
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Enclosure: AIT Report
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No. 50-440/93006(DRS)
See Attached Distribution
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APR 151993
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were lost at the time of pipe rupture. However, the team believes that the
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cause of the pipe rupture was local to the failure location and was not the
result of general system wide degradation. The local failure mechanism
concept appears to be supported by the absence of widespread cracking which
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would result from excessive bending or other gross loads during service.
Visual examination of exposed portions of the pipe, and the portions of the
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pipe removed during excavation, indicated that no significant system wide
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degradation or damage appeared to have occurred. However, due to the brittle
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nature of fiberglass pipe, it is susceptible to local damage. The possible
existence of other locally degraded locations cannot be ruled out without a
detailed inspection of the rest of the service water system.
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Your initial recovery from the event was thorough. However, corrective
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actions from a similar event in December 1991 had only partiality. been
implemented and, as a result, internal flooding that had occurred previously
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occurred again through the same or similar pathways.
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The team concluded that the operators safely responded in an excellent manner
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to the event and that their actions were indicative of a strong knowledge of
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plant systems and procedures.
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In accordance with 10 CFR 2.790 of the Commission's regulations, a copy of
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this letter and the enclosed inspection report will be placed in the NRC
Public Document Room.
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We will gladly discuss any questions you have concerning this inspection.
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Sincerely,
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A. Bert Davis
Regional Administrator
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Enclosure: AIT Report
No. 50-440/93006(DRS)
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See Attached Distribution
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APR I 5 893
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Distribution:
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F. R. Stead, Director, Nuclear
Support Department
D. P. Igyarto, General Manager,
Perry Nuclear Power Plant
Kevin P. Donovan, Manager,
Licensing and Compliance Section
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S. F. Kensicki, Director, Perry
Nuclear Engineering Dept.
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H. Ray Caldwell, General
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Superintendent Nuclear Operations
Licensing Fee & Debt Collection
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Branch
Resident Inspector, RIII
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Terry J. Lodge, Esq.
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James R. Williams, State of Ohio
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Robert E. Owen, Ohio
Department of Health
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A. Grandjean, State of Ohio,
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Public Utilities Commission
The Chairnian
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Commissioner Rogers
Commissioner Curtiss
Commissioner Remick
Commissioner de Planque
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D. C. Trimble, Jr. OCH
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D. A. Ward, ACRS
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J. M. Taylor, EDO
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J. H. Sniezek, DEDR
G. E. Grant, ED0
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T. E. Murley, NRR
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J. G. Partlow, NRR
J. W. Roe, NRR
J. A. Zwolinski, NRR
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J. N. Hannon, NRR
W. T. Russell, NRR
C. E. Rossi, NRR
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A. E. Chaffee, NRR
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R. L. Spessard, AEOD
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E. L. Jordan, AE00
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M. W. Hodges, RI
A. F. Gibson, RII
S. J. Collins, RIV
K. E. Perkins, RV
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AUGMENTED INSPECTION TEAM REPORT
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U.S. NUCLEAR REGULATORY. COMMISSION
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PERRY UNIT I SERVICE WATER PIPE BREAK
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APRIL 15, 1993
INSPECTION REPORT NO. 50-440/93006(DRS)
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TABLE OF CONTENIS
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1.0
Introduction ..............................................
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1.1
Event Summary .............................................
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1.2
Augmented' Inspection Team (AIT) Formation .................
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1.3
AIT Charter ...............................................
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2.0
Description of the Event ..................................
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2.1
Service Water System Description ..........................
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2.2
Sequence of Events ........................................
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2.3
Precursors to the Event ...................................
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2.4
Operator Response .........................................
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3.0
Event Classification and Reportina ........................
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4.0
Inspection Results ........................................
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4.1
Service Water Piping ......................................
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4.1.1
Performance History and Maintenance .......................
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4.1.2
Material Condition of Affected Piping . . . . . . . . . . . . . . . . . . . . .
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4.2
Flooding..................................................
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4.2.1
Amount of Water and Flood Path ............................
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4.2.2
Design of the Underdrain System . . . . . . . . . . . . ... . . . . . . . . . . . . .
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4.2.3
Water L evel fl ood Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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4.2.4
Conformance with the Updated Safety Analysis Report (USAR)
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As sumed Magni tude and Path . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 14
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(1) External .............................................
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(2)
Internal .............................................
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4.2.5
E f fec t s o f fl ood i ng . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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4.3
Eq u i pme n t P ro bl ems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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4.4
Rad i ol og i cal Rel ea se s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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S a fe t y Si on i fi c a n ce . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
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6.0
Corrective Actions for the December 1991 Circulatina Water
Line Break ..............................................
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6.1
Background ................................................
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6.2
Inspection ................................................
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7.0
Conclusions ................................................
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C h a r t e r C ompl e t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
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Exit Interview .................... ........................ 20
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Service Water System Piping Layout ................... Figure 1
Service Water Pipe Break Flood Path . . . . . . . . . . . . . . . . . . Figure 2
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March 30, 1993, CAL .............................. Attachment 1
AIT Charter ...................................... Attachment 2
Personnel Contacted . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Att achment 3
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