ML18052B396

LER 87-039-00:on 871030,discovered Charging Pump P-55B Would Not Automatically Actuate Pressurizer Low Level Signal W/Safety Injection Sys.Caused by Failure to Comply W/ Charging Needs.Corrective Action Under review.W/871130 Ltr

ML18052B396
Person / Time
Site:	Palisades
Issue date:	11/30/1987
From:	Johnson B, Kozup C CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-87-039, NUDOCS 8712040261
Download: ML18052B396 (8)

Text

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ltlMI LICENSEE CONTACT FOii THll LEll 1121 NAME TELEPHONE NUMIER AllEA CODE CSKozup, Technical Engineer, Palisades COM'LETE ONE LINE FOR EACH COMPONENT FAILUllE DEIClllllD IN THll llll'OllT 1131 CAUSE SYSTEM COMPONENT MANUFAC-TURER R~~o~;:g;E :1*1*:,:*1= :.:*:~: 1 :1: :i:i* : :.:.:*:1: :*:*.: 1: CAUSE SYSTEM COMl'ONENT MANUfAC-TUllER x I I I I I I I I I I I I I , .

I I I I I I I I I I I I I I SUPPLEMENTAL llEl'ORT IX,ECTED 1141 MONTH CAY viAR EX,ECTEC SUIM1$SIOl\I X1 YES (If 1'91. ~ EXl'ECTED SUllMISSION DATEI CATE 1151 AUTllACT (Lim/I ID 14()() -

• i.o .. -ro*imoroly ""'"" lingl**ll>>C* ry-irron /inn) 1111 Abs.tract During efforts to close out an NRC open item identified through the Palisades System Functional Evaluation (SFE) Program, it was determined that charging pump P-55B [CB;P] would not automatically: actuate upon a pressurizer [AB;PZR] low level signal with coincident SIS as previously thought . . This discovery resulted in the potential for past Plant operation outside of its design basis as described in Section 14.14, "Steam Line Rupture Incident" of the *Palisades Final Safety Analysis Report while operating within current Plant Technical Specifications (TS). The Plant was in cold shutdown condition when this item was identified.

8712040261 871130 PDR ADOCK 05000255 S PDR NllCFDml-19-831 LER 87-039A-NL02

'* NRC Form 368A U.&. NUCLEAR REGULATORY COMMISSION 19-831 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED OMS NO. 3150-0104 EXPIRES: 8/31 /85 FA.CILITY NAME 111 DOCKET NUMBER 121 LER NUMBER (61 PAGE 131 Palisades Plant 0 1s Io Io Io I 2 Is Is 81 7 - o 13 I 9 - ol o o I 2 oF o 15 TEXT (If morw -~a r.qllirwd, u* llddmon.J NRC Fonn ~*111171 Description During efforts to close out an NRG open item identified through the Palisades System Functional Evaluation (SFE) Program, it was determined that charging pump P-55B [CB;P] would not automatically actuate upon a pressurizer [AB;PZR] low level signal with coincident SIS as previously thought. This discovery resulted in the potential for past Plant operation outside of its design basis as described in Section 14.14, "Steam Line Rupture Incident" of the Palisades Final Safety Analysis Report (FSAR) while operating within current Plant Technical Specifications (TS). The Plant was in cold shutdown condition when this item was identified.

TS 3.2.2.a defines operational conditions of the Chemical and Volume Control (CVC) system [CB] necessary to assure safe plant operation and requires that "at least two charging pumps be operable" when the reactor is critical. However, it is not delineated as to which of the three charging pumps must be operable.

As stated in Section 14.14 of the Palisades FSAR, the limiting transient in the steam line rupture incident is a main steam line break (MSLB) accompanied by a loss of offsite electric power concurrent with the reactor trip. The loss of offsite power results in immediate coastdown of all four primary coolant pumps [AB;P]. The pump coastdown is turbine/generator [TA;TG] assisted and lasts for approximately 80 seconds at which time unassisted coastdown begins. Failure of one emergency diesel generator [EK;DG] is also assumed and reduces the number of available high pressure safety injection (HPSI) pumps [BQ;P]

from two to one and charging pumps from three to one. The maximum flow of borated water to the core is thus reduced by a factor of nearly three, relative to the maximum design flow rate. Charging flow of 34 gallons per minute is assumed to be available during this event. The transient response of the system to these events results in the lowest minimum departure from nucleate boiling ratio (MDNBR) of any of the main steam line break events considered in this analysis.

Other cases analyzed and presented in the Palisades FSAR assume 68 gallons per minute of available charging flow. One case considered is main steam line break coincident with loss of offsite power, turbine/generator assisted primary coolant pump coastdown and the failure of an auxiliary feedwater [SJ] control feature. Delivery of auxiliary feedwater to the steam generator [AB;SG] with the ruptured line is assumed to begin on reactor trip. Once established, flow is assumed to continue during the duration of the transient. The continued auxiliary feedwater flow adds positive reactivity to the core, enhancing the potential for additional fuel failure during a return to power event. In the initial analysis for this case, 68 gallons per minute of charging flow was assumed to be available based on the TS operability requirement for two charging pumps.

NRC FOAM 366.A 1s.s31 LER 87-039A-NL02

NRC Form 3HA U.li. NUCLEAR REGULATORY COMMISSION 19-831 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED OMB NO. 3150--0104 EXPIRES: 8/31 /85 c' FACILITY NAME (11 DOCKET NUMBER 121 LEA NUMBER 161 PAGE lll Palisades Plant 0 I5 I 0 I 0 I 0 I 2 I 5 I 5 817 - 0 I~ Iq - 0I0 0 I~ OF 0 I5 TEXT l/f motW - ia teq-. u* llddlrionM NRC Form .illS'4 'al 1171 An NRC open item (255/86035-137) was.issued following our discovery that charging pump P-55B would only start on a safety inje.ction signal (SIS) if a low flow condition existed. A low flow condition exists if less than one pump flow is sensed. The inspector.noted that certain FSAR MSLB analysis required 68 gallons per minute of charging flow to the core. This is equivalent to two charging pump flow. TS require that two pumps be operable, but do not delineate between specific pumps.

Therefore, if P-55A or P-55C was inoperable, as allowed by TS at the time of the event, only one pump flow would be present. This flow would not meet the 68 gallon per minute FSAR requirement. While reviewing this item it was further identified that P-55B would be enabled upon an SIS, however, would not actuate upon a low pressurizer level signal as previously thought, but only on low charging flow. Originally it was thought that P-55B would automatically actuate on low pressurizer level initiated by primary coolant system (PCS) shrinkage when the MSLB occurred.

A further review of steam line rupture incidents then identified that if the event (MSLB with coincident loss of offsite power) occurred when P-55C was out of service as allowed by TS, and the single active failure was diesel generator 1-2, no boric acid injection would be available via the charging pumps. Charging pumps P-55A and P-55B are powered by diesel generator 1-2, and P-55C by diesel generator 1-1. Prior to Plant restart from the ongoing Maintenance Outage, charging pump P-55B was declared admj_nistratively inoperable. By doing this, a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Limiting Condition of Operation (LCO) would be entered at any time P-55A or P-55C were removed from service. This action, permitted by TS, would provide for the availability of adequate charging flow to meet all FSAR MSLB analyses. Additionally at this time, Consumers Power Company Safety Analysis and vendor personnel began a review of charging needs for the MSLB analyses.

Cause Of The Event The failure to fully comply with the charging needs identified within the MSLB analyses has been attributed to a mis-identification of Plant design parameters and the lack of specificity within TS regarding charging pump operability requirements. This item was one of many FSAR questions which were derived from the Palisades SFE Program which were evaluated to determine priority of corrective action. The initial judgement 'that charging pump P-55B would actuate on low pressurizer level was thought to mitigate the concern regarding the lack of a SIS start input to P-55B and therefore, not given priority attention.

Corrective Action Charging pump P-55B was declared administatively inoperable. This action assured TS and MSLB analysis compliance. Actions were also NRC FOAM 366.A 19.a31 LER 87-039A-NL02

NRC Farm JIHIA U.S. NUCLEAR REGULATORY COMMISSION 19-831 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED OMB NO. 3150~104 EXPIRES: B/31185 FACILITY NAME 111 DOCKET NUMBER 121 LER NUMBER 181 PAGE 131

SEQUENTIAL ;:::::::::*REVISION YEAR :::::::::: NUMBER  :::::::::: NUMllE R Palisades Plant 0 I5 I 0 I 0 I 0 I 21 51 5 81 7 - 0 I 3 I 9 - 0 I0 0 14 OF 0 I5 TEXT llf,,,,,,.. ,,,... ;. fklund, u* ~ NRC F<Nm 3115111 '1) 1171 initiated by Safety Analysis and vendor personnel to determine the significance of the potential charging flow inadequacies.

SFE results were re-reviewed to identify other potential significant issues which should be given priority. Two additional items were identified which will receive priority over the remaining SFE items. An evaluation is in progress to determine an appropriate methodology for assuring that accident analysis bases reflect actual plant design and operating conditions.

An additional evaluation was undertaken to identify longer term actions which would resolve safety and administrative concerns. Current plans are to declare charging pump P-55B operable and place a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO on P-SSC when it is removed from service. This will provide con.sistency with current TS requirements, meet limiting case FSAR (see Analysis of the Event) charging needs of 34 gallons per minute and eliminate safety concerns. Additional items being studied for implementation include:

A modification which will permit P-SSB to be powered from either diesel generator 1-1 or 1-2. This will require manual transfer.

This modification will also ensure P-SSB receives an automatic actuation upon an SIS.

Replace existing part length control rods with full length, trippable rods.

Perform a complete MSLB re-analysis to document necessary corrections and more clearly identify operating parameters.

All the above actions are being evaluated to determine which, if any, will provide a cost beneficial alternative while maintaining nuclear safety.

Analysis Of The Event An evaluation by the fuel vendor shows that in scenariqs where 68 gallons per minute are currently specified providing 34 gallons per minute will result in decreased MDNBR's, however, all analyses are still bounded by the existing limiting MSLB analysis. An evaluation of the analysis by the fuel vendor utilizing zero charging flow indicates that the MDNBR remains unchanged for the most limiting case. However, further investigation is required regarding assumptions of boron addition beyond the analysis time frame.

NRC FORM 366A 1s-a 3 1 LER 87-039A-NL02

NRC Form 368A U.6. NUCLEAR REGULATORY COMMISSION 19-83)

LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED OMB NO. 3150-0104 EXPIRES: 8131185 FA*::ILITY NAME (1) DOCKET NUMBER 12) LER NUMBER 161 PAGE 131 Palisades Plant 0 I 5 I 0 I 0 I 0 I 2 I 5 I 5 81 7 - 0 I3 I9 - 0 I 0 0 I5 OF 0 I5 TEXT llf mar. -  ;. r.q-. u* llKkl-NRC Fonn JllliA'1I 1171 Administrative controls currently in place (P-55B declared administratively inoperable) and planned (placing a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO on P-55C only) meet FSAR MSLB analyses and thereby, eliminate any safety consequences. Future plans will be detailed in a revision to this Licensee Event Report. This revision is expected to be submitted by February 16, 1988.

This event is being reported in accordance with 10CFRS0.73 (a)(2)(ii) as a condition that is potentially outside of the Plant design basis.

\

NAC FORM 366/l 3

19*8 1 LER 87-039A-NL02

POWERI Nii MICHlliAN'S PROGRESS General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-0550 November 30, 1987 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -

LICENSEE EVENT REPORT 87-039 - POTENTIAL FOR OPERATION OUTSIDE OF DESIGN BASIS WITH RESPECT TO MSLB ANALYSIS Licensee Event Report (LER)87-039, (Potential For Operations Outside of Design Basis With Respect to MSLB Analysis) is attached. This event is reportable -to the NRC per 10CFR50.73(a)(2)(ii).

On October 20, 1987 a meeting was held at the Palisades Nuclear Plant with Messers B L Burgess, TV Wambach, TH Cox and ER Swanson to discuss the potential past Plant operation outside of its design basis regarding charging flow during main steam line break (MSLB) events. During this meeting, Mr B L Burgess requested a letter by November 30, 1987 which would discuss plans regarding charging pump operation. With the submittal of this letter and the information provided in the attached Licensee Event Report 87-039, "Charging Pump Actuation Logic Not Consistent With FSAR Design Basis", Consumers Power Company considers this commitment closed.

During efforts to close out an NRC open item identified through the Palisades System Functional Evaluation (SFE) Program, it was identified that charging pump P-55B would not automatically actuate upon a pressurizer low level signal with an SIS present as previously thought. This discovery resulted in the potential for past plant operation outside of its design basis as described in Section 14.14, "Steam Line Rupture Incident" of the Palisades Final Safety Analysis Report (FSAR) while operating within current Plant Technical Specifications (TS).

TS 3.2.2.a defines operational conditions of the Chemical and Volume Control (CVC) system necessary to assure safe plant operation and requires that "at least two charging pumps be operable" when the reactor is critical. However, it is not delineated as to which of the three charging pumps must be operable.

OC1187-0227-NL02 4i~

/ '\ \

-- 2 Present FSAR MSLB analyses were submitted in 1977 in support of an amendment request to increase power and in* 1981 as part of SEP (Systematic Evaluation Program). Section 14.14 of the FSAR provides information and analyses regarding several scenarios for MSLB. The limiting transient is a MSLB accompanied by a loss of offsite power concurrent with a reactor trip. The single active failure assumed during this event is a complete diesel generator failure to start. Accident analyses for this event assumes 34 gallons per minute of charging flow will-be provided to the core. Additional scenarios assume other active failures and assume 68 gallons per minute of charging flow to the core.

Prior to identifying that charging pump P-55B would not actuate on a safety injection signal (SIS) or low pressurizer level unless charging flow was less than 25 gallons per minute, the Plant was operated in accordance with TS. As stated above, TS require only two charging pumps be operable and do not delineate between the three available pumps. In order to determine Plant operation within its design basis as specified in Section 14.14 of the FSAR, Consumers Power Company Safety Analysis and vendor personnel began reviewing existing analysis assumptions and analyses for the effect of 34 and zero gallon per minute charging flow to the core. The results of the vendors evaluation indicates that for scenarios currently requiring 68 gallons per minute of charging flow, providing 34 gallons per minute of flow will lower the minimum departure from nucleate boiling ratio (MDNJIB-), but will remain within the most limiting transient. An evaluation of the analysis by the fuel vendor utilizing zero charging flow indicates that the MDNBR remains unchanged for the most limiting case. However, further investigation is required regarding assumptions of boron addition beyond the analysis time frame.

As discussed during the October 30, 1987 meeting, charging pump P-55B has been declared administratively inoperable. This action assures the Plant will enter a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Limiting Condition of Operation (LCO) when either charging pump, P-55A or P-55C are declared inoperable. It also assures charging flow limitations currently specified in the FSAR will be met. - After a preliminary review of alternative actions, current plans are to return P-55B to* operable status and place a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO on P-55C when it is removed from service. This will assure 34 gallon per minute charging flow requirements are met, with the loss of the diesel generator 1-2 feeding P-55A and P-55B, pending final resolution of the necessity of any charging flow. Current Plant design will permit actuation of P-55B if P-55A is out of service and the active failure is diesel generator 1-1.

Additional alternatives are being studied, however, due to the significant scope of the alternatives, a final action plan has not yet been formulated.

Alternatives being studied include:

- Perform a modification which will allow P-55B to be powered from either diesel generator. This will require a manual transfer to diesel generator OC1187-0227-NL02

• 3 1-1 when P-55C is removed from service. This modification will also ensure P-SSB receives an automatic actuation upon an SIS. Currently, P-SSB is powered from diesel generator 1-2 and does not automatically actuate upon an SIS unless total charging flow is less than 25 gallons per minute.

Permanently requir~ the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> LCO limitation on P-55C pump through formal change to the Technical Specifications.

- Perform a complete re-analysis of the MSLB. Because the model would require upgrading, this is a one year effort.

- Perform a modification which would replace the existing part length control rods with full length trippable control rods. An evaluation will first be done to determine if this eliminates the specific need for charging flow during Plant transients by immediate addition of sufficient shutdown margin.

The scope of the first three alternatives is both capital and time intensive. It is expected that cost/benefit analyses and a final action plan will be complete by early February 1988. Consumers Power Company will inform the Commission as to its plans via a revision to the attached Licensee Event Report. We expect to submit this revision by February 16, 1988.

Brian D Johnson Staff Licensing Engineer CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment OC1187-0227-NL02