05000305/LER-2005-004, Regarding Safe Shutdown Potentially Challenged by Unanalyzed Internal Flooding Events and Inadequate Design

Regarding Safe Shutdown Potentially Challenged by Unanalyzed Internal Flooding Events and Inadequate Design

ML051440302
Person / Time
Site:	Kewaunee
Issue date:	05/16/2005
From:	Lambert C Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC-05-063 LER 05-004-00
Download: ML051440302 (5)

LER-2005-004, Regarding Safe Shutdown Potentially Challenged by Unanalyzed Internal Flooding Events and Inadequate Design

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor
3052005004R00 - NRC Website

text

Kewaunee Nuclear Power Plant Committed to Nuctear Operated by Nuclear Management Company, LLC May 16, 2005 NRC-05-063 10 CFR 50.73 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Kewanee Nuclear Power Plant Docket 50-305 License No. DPR-43 Reportable Occurrence 2005-004-00 In accordance with the requirements of 10 CFR 50.73, "Licensee Event Report System," a Licensee Event Report (LER) for reportable occurrence 2005-004-00 is being submitted.

This letter contains no new commitments and no revisions to existing commitments.

Craig W. Lambert Site Vice President, Kewaunee Nuclear Power Plant Nuclear Management Company LLC Enclosure (1) cc:

Resident Inspector, Kewaunee, USNRC Project Manager, Kewaunee, USNRC Administrator, Region ll, USNRC INPO Records Center N490 Highway 42 *. Kewaunee, Wisconsin 54216-9511 Telephone: 920.388.2560

.ENCLOSURE1 LICENSEEEVENTREPORT(LER) 2005-004-00 3pagesfollow

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 EXPIRES 6-30-2007 (6-2004)

Estimated burden per response to comply with this mandatory collection request 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br />.

Reported lessons learned are incorporated into the licensing process and fed back to industry.

LICENSEE EVENT REPORT (LER)

Send comments regarding burden estimate to the Records and FOLAlPrivacyService Branch (T-5 F52). U.S. Nuclear Regulatory Commission, Washington, DC 205554001, orbyintemete-(See reverse for required number of mail to Infocollects~nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs. NEOB-1 0202. (3150-0066), Office of Management and Budget. Washington. DC 20503 digits/characters for each block)

If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

FACILITY NAME (1)

DOCKET NUMBER (2)

PAGE (3)

Kewaunee Nuclear Power Plant 05000305 1 of 3 TITLE (4)

Safe Shutdown Potentially Challenged By Unanalyzed Internal Flooding Events and Inadequate Design EVENT DATE (5)

LER NUMBER (6)

REPORT DATE ()

[

OTHER FACILITIES INVOLVED (8) l FACILITY NAME DOCKET NUMBER SEQUENTIAL I REV MO DAY YEAR YEAR NUMBER lNO MO DAY YEAR 03 15 2005 2005 004 -- 00 05 16 2005 FACILITYNAME DOCKETNUMBER OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR.: (Check all that apply) (11)

MODE (9)

__ 20.2201(b) 20.2203(aX3)(ii)

X 50.73(a)(2)(iiXB) ll 50.73(a)(2Xix)(A)

POWER 000 20.2201(d) 20.2203(aX4) 50.73(a)(2)(iii) 50.73(a)(2Xx)

LEVEL (10) 0 20.2203(aXl) 50.36(cXl)(i)(A) 50.73(a)(2)(iv)(A) 73.71(a)(4)

_ 20.2203(aX2)(i) 50.36(cX1)(iiXA)

X 50.73(aX2)(v)(A) 73.71 (a)(5)

- _ 20.2203(aX2)(ii) 50.36(cX2) 50.73(a)(2)(v)(B)

OTH ER 20.2203(aX2)(iii) 150.46(aX3)(ii) 50.73(a)(2)(v)(C)

Specify In Abstract below or in

__ 20.2203(a2)(iv)

= 50.73(a2)(iXA)

_50.73(a)(2)(v)(D)

_NRC Form 366A

__20.2203(aX2)(iv) 50.73(aX2)(iXA) 150.73(aX2)(vi)(D 20.2203(a)(2)(v) 50.73(aX2)(iXB) 50.73(a)(2)(vii)

X20.2203(aX2)(vi)

_50.73(a)(2)(i)(C)

=

07()(2)(viii)(A)

[

20.2203(aX3)(i) 50.73(aX2)(ii)(A) 50.73(aX2)(viii)(B) l_

LICENSEE CONTACT FOR THIS LER (12)

Mar A

oMr TFI FPWAnNJ Ml MIAR;FP In-

. Ares Mary Jo Merholz 1920-388-8277 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANU_

REPORTABLE I I

ANU-REPORTABLE

CAUSE

SYSTEM COMPONENT FACTURER TO EPIX

=

CAUSE

SYSTEM l

COMPONENT I

FA CTURER TO EPIX SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR X I YES (If yes, complete EXPECTED SUBMISSION DATE).

NO SUBMISSION 07 30 2005 DATE (15)

ABSTRACT On March 15, 2005 with the plant in Refueling Shutdown Mode, NMC personnel determined that the Kewaunee plant design for protection against internal flooding would not ensure that required equipment would be protected from the postulated failure of non-safety related piping in the turbine building. High water level in the turbine building would result in water flowing into certain Engineered Safety Features equipment rooms.

Documentation which considers specific flooding events from postulated failures of plant equipment exists, however, a complete internal plant flooding analysis was not developed during or subsequent to the plant's original design. In response to inadequate plant design, physical changes are being made to minimize challenges to plant equipment and personnel in combating potential flooding events. Analysis continues to determine the potential for and effects of flooding events occurring, and to enhance and document the plant's design for internal flooding. Although this LER is not associated with an event resulting in actual flooding of any portion of the plant, the potential for certain piping and tank failures resulting in unacceptable flooding exists. A past operability evaluation is underway to assess what equipment would have failed during postulated flooding events. The Significance Determination Process will be used to assess the safety consequences and implications for any equipment that would have failed. This information will be addressed in a supplement to this LER. This report does not involve a safety system functional failure.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

I SEQUENTIAL I REVISION Kewaunee Nuclear Power Plant 05000305 YR NUMBER NUMBER 2of3 2005 -

004 -

00 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)

Event Description

On March 15, 2005 with the plant in Refueling Shutdown Mode, NMC personnel determined that the Kewaunee plant design for protection against internal flooding would not ensure that required safety-related equipment would be protected from the failure of non-safety related piping [PSP] in the turbine building [NM].

High water level in the turbine building would result in water flowing into certain Engineered Safety Features (ESF) equipment rooms. The ESF equipment rooms are separated from the remainder of the turbine building by non-water-tight doors and the plant floor drain system. The ESF equipment rooms contain the Auxiliary Feedwater (AFW) pumps, Emergency Diesel Generators (EDG) and both the 480 volt and 4160 volt electrical ESF switchgear. The water could reach levels that may result in failure of certain ESF and plant safe shutdown equipment.

Documentation that considers specific flooding events from postulated failures of plant equipment exists, however, a complete internal plant flooding analysis was not developed during or subsequent to the plant's original design. Information describing the plant's design for internal flooding events is limited.

Event Analysis and Safety Significance This event is being reported under 1 OCFR50.73(a)(2)(ii)(B), any event or condition that resulted in the plant being in an unanalyzed condition, and 1 OCFR50.73(a)(2)(v)(A), any event or condition that could have prevented the fulfillment of the safety function of structures or system that are needed to shut down the reactor and maintain it in a safe shutdown condition. This event was initially reported on March 15, 2005 as a 1 OCFR50.72 non-emergency event under criterion (b)(3)(ii)(B), unanalyzed condition, and criterion (b)(3)(v)(A) safe shutdown capability (reference Event Notification EN 41496).

Subsequent to the initial report on March 15, 2005, analysis continues of the assumed piping system failure with the potential loss of ESF equipment. The results of the analysis and the evaluation will be included in a supplement to this LER.

This LER is not associated with an event resulting in actual flooding of any portion of the plant. However, because of inadequate plant design and a lack of clear guidance on the full scope of assumptions needed to substantiate the plant's ability to meet the design basis, the potential for flooding events and their potential consequences are under evaluation. A past operability evaluation is underway to assess what equipment would have failed during postulated flooding events. The Significance Determination Process will be used to assess the safety consequences and implications for any equipment that would have failed. This information will be addressed in a supplement to this LER.

This report does not involve a safety system functional failure.

Cause

A Root Cause Evaluation (RCE) is in progress to determine the cause and full scope of corrective actions.

Following completion of the root cause the causal information will be submitted in a supplement to this LER.U.S. NUCLEAR REGULATORY COMMISSION (1-2001)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1)

DOCKET NUMBER (2)

LER NUMBER (6)

PAGE (3)

YEAR SEQUENTIAL I REVISION Kewaunee Nuclear Power Plant 05000305 Y

NUMBER NUMBER 3 of 3 2005 004 00 TEXT (If more space is required, use additional copies ofNRC Form 366A) (17)

Corrective Actions

The corrective actions that have been implemented or are currently in progress are:

1. A design and licensing basis for internal flooding is being compiled to support current and future design.

2. The following actions have been initiated until the appropriate measures to ensure protection of Class I plant structures and components as defined in KNPP's Updated Safety Analysis Report (USAR) have been completed:

a. Plant operating mode has been restricted to refueling or cold shutdown.

b. The combined inventory of Condensate Storage Tanks and Reactor Makeup Storage Tanks has been limited.

c. Restrictions have been put in place for operating the Circulating Water and Condensate Systems.

3. Seismic qualification of selected unqualified piping and components.

4. The design modifications in progress to protect Class I plant structures and components as defined in KNPP's USAR include:

a. Installation of Check Valves in Floor Drains from Cardox Room, Safeguards Alley, Bus 1 and 2 Rooms.

b. Revise Auxiliary Feedwater Pump Lubricating Oil Coolers and Drain Flow Path.

c. Flood Barriers at Doors to Safeguards Alley.

d. Circulating Water Pump Trip on High Turbine Building Basement Water Level.

e. Turbine Building Auxiliary Feedwater Pump Steam Supply Piping Support.

Additional information regarding the corrective actions relative to this event will be provided as a supplement to this LER.

Previous Similar Events

Similar Events will be determined upon completion of the root cause evaluation.