IR 05000266/1996013

Insp Repts 50-266/96-13 & 50-301/96-13 on 961003-1115.No Violations Noted.Major Areas Inspected:Reviews of Interim Operability Determinations for Selected Pumps & Portions of Related Design Basis Calculations

ML20133A354
Person / Time
Site:	Point Beach
Issue date:	12/20/1996
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20133A348	List: IR 05000266/1996013 ML20133A345
References
50-266-96-13, 50-301-96-13, NUDOCS 9612310057
Download: ML20133A354 (9)

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I- U.S. NUCLEAR REGULATORY COMMISSION REGION lli

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Docket Nos: 50-266; 50-301 License Nos: DPR-24; DPR-27  ;

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l i i Report Nos: 50-266/96013(DRP); 50-301/96013(DRP) l

$ i Licensee: Wisconsin Electric Power Company i 4 ,

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Location:

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6612 Nuclear Road  ;

Two Rivers, WI 54241 l l

Dates: October 3 through November 1'5,1996

Inspectors: J. A. Gavula, Reactor Inspector !

G. F. O'Dwyer, Reactor Engineer )

C. W. Keller, Resident inspector )

Approved by: J. W. McCormick-Barger, Team Leader Point Beach Oversight Team l

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9612310057 961220 PDR ADOCK 05000266 G pm  :

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! EXECUTIVE SUMMARY I

I 4 Point Beach Nuclear Plent, Units 1 and 2

, NRC Inspection Report No. 50-266/96013(DRP); 50-301/96013(DRP)

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i This special inspection included reviews of interim operability determinations for selected l

l pumps and portions of related design basis calculations. The report covers a period from l October 3 through November 15,1996. This inspection was initiated as a result of

concerns identified in NRC Inspection Report No. 50-266/96006(DRP); 50-

, 301/96006(DRP) relating to the adequacy of the inservice Testing acceptance criteria.

Engmeenna l e The interim operability determinations provided reasonable assurance that pumps l- would perform within the required design bases. However, final determinations will

! need to be reviewed after instrument inaccuracies have been incorporated into the I inservice Testing acceptance criteria.

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l e The recent changes to the service water system combined with other changes I j affecting the containment integrity analysis have caused the design and licensing

] bases to be queationed. This issue will be tracked as an inspection followup item

, pending NRR review and resolution with licensee staf e The preliminary reviews to ensure design requirements were incorporated when l establishing acceptance criteria for inservice testing for safety-related pumps were

! initiall.c poorly defined and were not formalized. Documenting the basis for the

! operability of potentially degraded equipment is a fundamental concept for a sound i corrective action program. Even after the NRC staff identified the lack of formal i documentation, the licensee initially questioned the need to document the j operability determinations.

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Renort Databs m. Enginsedna E1 Conduct of Enginsedng E1.1 Pumo Onorability Determinations Insoection Scone (92903)

The inspectors reviewed the licensee's interim operability determinations for pumps that potentially had non-conservative inservice testing (IST) acceptance criteri The issue, initially identified as Inspection Followup Item (IFl 50-266/96006-01(DRP): 50-301/96006-01(DRP)), involved acceptance criteria for the Safety injection pumps that met American Society of Mechanical Engineers (ASME)

IST program requirements, but did not ensure that the pumps met the required design bases. Specifically, the acceptance criteria in the licensee's IST program

! could allow a pump's performance to degrade to the extent that the pump could

} not deliver the flow assumed in the accident analyse Observations and Findinas

i The licensee initially did not recognize the need to formalize the operability basis for j pumps that potentially had non-conservative IST acceptance criteria. The corrective actions for the condition report associated with the safety injection pump did not require operability determinations on other pumps. As a result, when the

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initial operability determinations were subsequently documented, they were not captured by the licensee's corrective action program. The initial determinations

were ultimately prepared, reviewed, and approved, but were not designated as retrievable documents. The licensee pointed out that the final determinations would be part of a retrievable vehicle recognized by the quality assurance program. The  !

l inspectors reviewed the following interim operability determinations for pumps that potentially had non-conservative inservice testing (IST) acceptance criteria:

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e Auxiliary Feedwater (AFW) Pumos - The operability determination for the AFW pumps referred to calculation N-94-158, " Verification of Required AFW j Pump Differential Head for Accident Flow Rate," which determined the '

, minimum required AFW pump head to meet accident flow rates. The smallest margin between the minimum required head and the recent IST test data was 3 percen e Residual Heat Removal (RHR) Pumos - The operability determination verified j that the assumed RHR pump design basis was conservative for accident analyses. The IST acceptance criteria would not allow operation outside of

design basis value I

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e Component Cochng Water (CCW) Pumos - The operability determination calculated the design basis flow requirements by combining the flows for the

! RHR heat exchanger, given in Final Safety Analysis Report (FSAR) Section 9.3, with flows to other components. The margin between the design basis flow requirements and the test data provided in the operability determination was 3.g percen o Containment Sorav (CS) Pumos - A preliminary calculation, referenced in the operability determination, determined that the CS pumps could degrade up to 15 percent and still satisfy design basis flow rates. The inspectors noted that the polynomial curve fit used in the calculation to approximate the CS

! pump performance curves overestimated the performance of pump 1-P14A

by about 1 percent at the design basis flow rate. This overestimation was not considered in determining the IST acceptance criteria. The test data provided in the operability determination showed that the worst pump had only degraded by about 7.7 percent from the original pump curve e Service Water (SW) Pumos - The operability determination noted that pump design basis flow rates were determined in Calculation No. 96-0117,

" Containment Fan Cooler Service Water Throttle Valve Set Point for Three l Service Water Pump Operation." Based on limited. reviews of this

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calculation, the inspectors identified several concerns regarding changes to the design basis of the SW system. These concerns are discussed further in Section E1.2 of this report. Flow rates recorded for each of the six SW j pumps during recent inservice testing exceeded the design basis flows j specified for each pump in the operability determination.' l j

e Boric Acid Transfer Pumos - The operability determination noted that the l design basis of these pumps was given in FSAR Section 9.2.1. Inservice l testing measured the pumps' discharge pressure while operating at the

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design basis flow rate. The latest test results indicated that worst of the

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four pumps had approximately 2.7 percent of margin above the design basis l discharge head. The inspectors noted that the licensee had identified a need i to change the design basis information in the FSAR to account for the previous installation of a discharge orifice, o Control Room Ventilation Chiller Pumos - The operability determination noted that the maximum cooling load associated with these pumps was determined in calculation WEPOO8.0601. Based on heat exchanger design  ;

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capacities and the latest IST pump flow rate, the expected heat removal rate was approximately 30 percent greatec than the maximum heat loa * Cable Sorsadina Room Ventilation Chiller Pumos - The operability determ%ation noted that the maximum cooling load associated with these I pumps was determined in calculation WEPOO8.0601. Based on heat exchanger design capacities and the latest IST pump flow rate, the expected heat removal rate was greater than twice the maximum expected heat loa . 4 l

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e Charmng Pumns - The operability determination evaluated normal operating '

requirements, Technical Specification (TS) boration volume requirements, and FSAR makeup flow rate requirements and concluded that the normal i operating flow rate was the most limiting design basis requirement. Recent j IST tests determined that the most limiting pump provided 33 percent greater flow than required under normal system operating pressur e Fuel Oil Transfer Pumns - The operability determination noted that the design '

basis flow rate was 20.5 gallons por mmute (gpm) and that the latest IST '

result for the lowest pump was 37 gp e Spent Fuel Pool Cooling Pumns - The operability determination noted that the ,

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design flow rate, established in the FSAR, was 1250 gpm. The IST '

acceptance critoria would not allow operation outside of design basis salue Conclusions

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The inspectors concluded that tae interim operability determinations for the pumps provided reasonable assurance that the pumps would perform within the identified design bases. Although the interirn operability determinations did not specifically consider instrument inaccuracies, either several percent margin was shown to be available relative to design basis requirements, or the pumps were tested in the design basis configuration. Pending a review of the final operability determinations that include instrument inaccuracies, IFl 50-266/96006-01(DRP); 50-301/96006-01(DRP) will remain ope ,

l E1.2 Service Water and Related Desian Basis lasues Insoection Scone As noted above, the inspectors reviewed limited portions of the SW system design basis calculation, No. 96-0117, and noted that the design basis heat removal rate '

for the containment fan coils (CFC) had to be reduced to resolve a two-phase flow problem. Since this impacted the containment performance, the inspectors reviewed limited portions of the licensee's safety evaluation SER 96-055,

" Containment Integrity Evaluation with Reduced Fan Cooler and Containment Spray Performance." Observations and Findinas During reviews of SER 96-055, inspectors identified the following concerns:

e The licensee did not demonstrate that the containment pressure profile assumed in the dose calculations was more conservative than the revised pressure profile. The offsite and control room dose analyses assumed that containment pressure would be less than 15 pounds per square inch gauge  !

(psig) after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. However, the revised containment analysis stopped after roughly 12.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> at a pressure greater than the assumed 15 psi :

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Although the pressure profile could be extrapolated to conclude that 15 psig would be reached within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, this was not demonstrated in the analysi e ' The revised containment pressure profile showed that the pressure decreased to about 22 psig for approximately 400 seconds at the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> point and then increased above 23 peig for the next 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. Since the post-accident air sampling pump motor was designed to operate at pressures ,

less than 23 psig, the revised pressure profile potentially limited the ability to i promptly obtain a sample as directed by NUREG 0737. Section 2.B.4 of the l licensee's SER stated that there was no requirement or commitment for the l post-accident sampling system design to be based on the extremely

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conservative assumptions used in the containment integrity analysis. The  ;

inspectors questioned the validity of the licensee's statemen .e The licensee concluded that two-phase flow will occur in the SW piping i downstream of the CFC SW throttle valves, and modeled this using a single- j phase flow computer code. The licensee benchmarked the performance of l this code using engineering judgement and the RELAP5 computer code. The  !

inspectors questioned the validity of the licensee's methodology for  !

evaluating two-phase flow using a single-phase flow computer cod e Although the licensee concluded that two-phase flow would occur

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downstream of the CFC throttle valves, piping and pipe supports were not evaluated for the hydrodynamic loads associated with subsequent void ,

collapse. The magnitude of these loads may depend on the validity of the l above flow modeling concer l

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e Because the licensee reduced the heat removal capacity of the CFCs, the TS !

statement regarding the total heat removal capability of the ventilation fans !

and air coolers can no longer be achieved. Although a TS amendment to j correct this is currently pending with the NRC, the change required 4

. Commission approval prior to reducing heat removal capacity of the CFC .

e The original containment integrity evaluation assumed heat removal only through the CS system and the CFCs. However, the revised evaluation assumed that RHR/CCW systems will provide heat removal during the recirculation phase of a design basis accident. This change to the containment analysis assumptions did not appear to have been properly  !

considered relative to the pending TS amendment pertaining to the service water and emergency core cooling systems (Change Request 192). Conclusions l Since the above concerns related to original design bases or licensing bases of the plant, they were referred for review and evaluation to the Office of Nuclear Reactor ;

Regulation (NRR) through a Task Interface Agreement. This will be tracked as an l Inspection Followup item 50-266/96013-01(DRP); 50-301/96013-01(DRP). I t

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X1 Exit Meeting Summary The inspectors presented the interim inspection results to licensee representatives on October 8,1996. The licenses acknowledged the findings presente The inspectors asked the licensee whether any materials examined during the inspection were proprietary. No proprietary information was identified.

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PARTIAL UST OF PERSONS CONTACTED Wisconsin Electric Power Comoany S. Patulski, Site Vice President J. Schweitzer, Senior Site Engineering Manager A. Cayia, Plant Manager W. Fromm, Maintenance Manager T. Guay, Regulatory Services Mana0er

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INSPECTION PROCEDURES USED

IP 92903: Followup - Engineering

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ITEMS OPENED, CLOSED, AND DISCUSSED

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Opened 50-266/96013-01(DRS); IFl Design basis questions for containment integrity 50-301/96013-01(DRS) analysis and service water system

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, 50-266/96006-01; IFl IST Program deficiencies 50-301/96006-01 a

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i LIST OF ACRONYMS USED AFW Auxiliary Feedwater ASME American Society of Mechanical Engineers CCW Component Cooling Water CFC Containment Fan Cooler CFR Code of Federal Regulation l CS Containment Spray FSAR Final Safety Analysis Report j gpm gallons per minute l IFl Inspection Followup item IP Inspection Procedure IST inservice Testing NRC Nuclear Regulatory Commission NRR Nuclear Reactor Regulation psig pounds per square inch gage RHR Residual Heat Removal SER Safety Evaluation Report TS Technical Specification URI Unresolved item i

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