ML19340C135

Confirmatory Deficiency Rept Originally Reported on 801008 Re Effect of Failure of Component Cooling Water on Nonessential & Essential safety-related Portions.Component Cooling Water Surge Tank Level Will Be Maintained

ML19340C135
Person / Time
Site:	Midland
Issue date:	11/07/1980
From:	Jackie Cook CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
10053, 10CFR-050.55E, 10CFR-50.55E, NUDOCS 8011140038
Download: ML19340C135 (7)

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, 7 s cm,on. u.ch 2.n Novenber 7,1980 Mr J G Keppler, Regional Director Office of Inspection ?4 Enforcement US Nuclear Regulatory Commission '

Region III 799 Roosevelt Road Glen Ellyn, IL 00137 MIDLA'!D NUCLEAR PLA'iT UNITS 1 AND 2, DOCET NOS 50-329, 50-330 COMPONENT COOLING WATER DESIGN FILE: 0.h.9.h3 UFI: 73*10*01, lolll(S) SERIAL: 10053 This letter confirms the 50.55(e) item concerning the effect of failure of the nonessential portion of the component cooling water (CCW) on the essential (safety-related) pcrtion of the CCW. This conditicn was reported by telephcne call to R Knop and R Sutphin, USNRC Region III, Glen Ellyn, IL, on October 6, 1980.

The attachments to this letter describe the conditions and actions being taken concerning this item.

Another report, either interim or final, will be sent on or before January 30, 1981.

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WRB/lr Attnehments: 1)' Management Corrective Action Report (MCAR-1), Report No h3, dated October 10, 1980 1

2) MCAR h3, Interim Report 1, Component Cooling Water System l Susceptibility to Loss of Coolant Accident Induced Failures, dated October 31, 1980 CC: Director of Office of Inspection & Enforcement Att Mr Victor Stello, USNRC (1,5)

Director, Office of Management Information & Pror.rna Control, USNRC (1)

RCook, USNRC Fecident Inspector Midland Nuclear Plant (1)

$0]114 0 0 38

2 Serial 10053 CC: CBechhoefer, ASLB Panel GALinenbercer, AGLB Panel FPCowan, ASLE Panel AG?nL Appeal Panel MMCherry, Esq MSinclair CH3tephens, USNRC WDPaton, Esq, USNRC FJKelly, Esq, Attorney General SHFreeman, Esq, Asst Attorney General GTTaylor, Esq, Asst Attorney General WHMarshall CJMerritt, Esq, TNK&J Great Lakes QA Managers 9

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QUALuiV MSSUMMNCF PROGRAM Serial 10053 l

, MANAGEMENT CORRECTIVE ACTION REPORT MCAR-1 l

, REPORT NO.: 43 JOB NO.: 7220 0 l 3 7 7 ENO.: DATE: October 10, 1980 l l DESCRIPTION * (including References):

Contrary to the safety design bases in FSAR Subsection 9.2.2, the component cooling water (CCW) system may be susceptible to LOCA-induced failures that, in conjunction with a loss of offsite power and a single active failure, could result in complete loss of the system's safety function. Non safety-related CCW lines located inside the containment are not designed for or specifically protected against the effects of a RECOMMENDED ACTION * (Optionai):

1. Develop and submit a written report to the AA0 PQAE staff containing all available information on or before October 27, 1980 for coordination with the Consumers Power Company.

REFERRED TO: Z Engineering C Construction O OA Management O O Procurement ISSUED Q [d 10/10/80 d L.A. Dreisbach Protect GA Engineer Date l Telcon J.A. Rutgers to J.W. Cook 11 REPORTABLE DEFICIENCY: l Potentially NOTIFIED CUENT: 10/08/80 9:00 a.m.

Reportable o.s.

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Ill CAUSE:

CORRECTIVE ACTION TAKEN:

AUTHORIZED BY:

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heGR OF PnXUpf MENY PFOCE LAPO - Q A MGR MGR Of PH0J OrtR AT10Ns PROJECT CONSTR MGR SFPD . Q4 MGR uGR Or cUrur, assuaixE Pac 2ECT EetER CONSTRUCTON MGR PfaQa[Cy McA CORRECTIVE ACTION IMPLEMENTED ENGWE E HiNG UCA PRoJ PROCUREMENT MGR SUPPLit R QU4Lif Y boGR SITE MGR Ce soPERvisOR l

VERIFIED BY

• Descret,o en space prowded and affaCh reference dOCumOr,t Pewt C A En;pneer De, cm m Section Numt:cr Page of

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I DESCRIPTION - Cont. 013775 LOCA (e.g. , ia, impingement) .

The isolation valves have closure times of 60 to 75 seconds, exclusive of )

signal' delay times or diesel generator startup time. These closure times  !

are inadequate to isolate a gross failure in the nonsafety-related portions of the system before the CCW surge tank c ptics.

If a singic active failure is postulated to concurrently disabic the opposite CCW safety train, the unit will lose CCW heat transfer capability. Following a LOCA, CCW capability is required to transfer heat from the DHR heat exchangers within approximately 22 minutes, and from the DHR, high-pressure injection, and reactor building spray pump coolers within approximately 30 minutes. The engineered safety features pumps have not been evaluated to determine their capability to operate without cooling water.

The CCW system, as presently designed, would accommodate minor leaks in the nonsafety-related portion of the system prior to closure of isolation valves and still allow the safety-related portion of the CCW system to perform its functions but the system is not designed to withstand a full break of the non-seismic CCW piping. Therefore, for completeness, further evaluation of seismic induced stresses and their probable effects is necessary to establish the adequacy of design for the design basis seismic event (SSE) .

II RECOMMENDED ACTION - Cont.

, 2. Perform related high energy line break analysis (HELBA) and seismic analysis to establish the impact on the portion of CCW piping in question.

3. Make a final determination on the reportability of this item as soon as sufficient data is available.

4. Investigate and identify the root cause and provide corrective action to preclude recurrence.

5. Determine if other similar/associsted problems exist.

6. Determine the necessary system changes to bring the CCW design in conformance to the applicable design criteria.

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I Serial 10053 Bechtel Associates Professional Corporation OI5296

SUBJECT:

MCAR 43 (issued 10/10/80)

Component Cooling Water System Susceptibility to Loss of-Coolant Accident-Induced Failures INTERIM REPORT 1 DATE: ,0ctober 31, 1980 PROJECT: Consumers Power Company Midland Plant Units 1 and 2 Ecchtel Job 7220 Introduction This report describes the interim status of project activities concern-ing component cooling water (CCW) system susceptibility to loss-of-coolant accident (LOCA)-induced failures.

Description of Deficiency l

The Midland Units 1 and 2 CCW system is a dual purpose system serving both safety and nonsafety-related equipment. For each unit, redundant CCW pump trains supply cooling water to the associated high pressure injection (ilPI) makeup pump lube oil coolers, reactor building spray pump, decay heat removal (DilR) pump seal coolers, and DHR heat exchangers following a LOCA; and to nonsafety-related heat exchangers during normal power operation. The nonsafety-related loads are supplied by either CCW i train during normal power operation while the redundant CCW punp train  !

is on stendby. The 16- and 18-inch motor-operated butterfly valves I isolating nonsafety-related loads from the CCW pump trains have a valve closing time of 60 to 75 seconds, exclusive of delay in the control signal to activate them. Each CCW pump train has a CCW surge tank with a total capacity of 1,000 gallons and a nominal minimum operating level of 300 gallons, with a nonseismic makeup from the demineralized water storage and transfer system.

Nonseismic CCW piping to the reactor coolant pump motor coolers, letdown coolers, and control rod drive mechanism in the reactor building may not be adequately protected from LOCA-induced failures such as jet impinge-ment or pipe whip; other CCW piping to the radwaste evaporator condenser in the auxiliary building is not designed as Seismic Category I. There-fore, the piping may not retain its integrity.under LOCA-induced failures or during a seismic event.

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015296 HCAR 43 Page 2 If a pipe break were to occur in CCW piping because of LOCA-induced failures or a seismic event where the line is not specifically designed to withstand cuch an event and its consequences, the CCW surge tank Icvel would drop. For Unit 1, CCW train A, the CCW surge (IT-73A) low-low level signal will trip its associated CCW pump (IP-73A) and initiate closure of its associated motor-operated safety-related loop isolation valves (IM-1610A and IM0-1623A) isolating all nonessential components from the CCW system. This scenario is analogous for each CCW train in both units. If an emergency core cooling actuation signal (ECCAS) occurs, the CCW surge tank low-low level trip signal to the CCW pump will be bypassed, the CCW pump will start, and the safety-related loop

isolation valves will close.

j With a pipe break in a line not specifically designed to withstand the postulated seismic event, the operating CCW surge tank Icvel could drop to the low-low level setpoint and the closure of the safety-related loop isolation valves will then be initiated. However, because of the slow (60-75 seconds) closure time of the isolation valves, enough water could be lost from the CCW system before the valves completely close that the net positi.2 suction head (npsh) available to the CCW pump would be inadequate. An ECCAS signal would restart the tripped CCW pump, which could result in loss of CCW flow and pump cavitation because of low npsh availability. The standby CCW train is postulated to be unavailable because of a concurrent single active component failure. Thus, the unit would have lost CCW heat transfer capability.

Potential Safety Implications The design deficiency has no effect on the nornal safe operation of the plant. However, following a LOCA, CCW capability is required to trans-fer heat from the DilR heat exchangers within approximately 22 minutes, and from the DllR pump seal coolers, reactor building spray pump seal coolers, and 11PI makeup pump lube oil coolers within approximately 30 minutes. It cannot be ensured that these requirements allow sufficient time following a LOCA to restore the Icvel to the surge tank and restore flow to required compnents. The capability of the engineered safety features pumps to operate without cooling water has not been evaluated.

The capability of the containment air coolers to renove heat is not j affected by this scenario.

Because the current design is a significant deliciency in final design as approved and released for construction such that the delsgn does not con-form to the criteria and bases stated in the safety analysis report and l .

could have an adverse inpact on plant safety throughout the expected life of the plant, the design deficiency is reportable under 10 CFR 50.55(e).

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015296 HCAR Page 3 Corrective Action Corrective action will be taken to ensure that the CCW surge tank level is maintained to ensure adequate npsh for safe operation of CCW pumps and that the design conforms to the design basis stated in the final safety analysis report (FSAR). Therefore further high-energy line break analysis and seismic analysis of the CCW piping under question will not be pursued. It has been determined, af ter reviewing other systems, that similar associated problems would not occur in other systems because the CCW system is the only closed-loop, dual purpose system in the plant.

Design for the corrective actica is proceeding. The cause of the defi-ciency and design details for corrective actions are being reviewed and will be discussed in the next report, which will be provided by January 16, 1981. )

l Prepared by: , _, t. , . /~ l Approved by: k J. A c.r- bC%

Concurrence by: / d '/ l l

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