NPL-98-0718, Forwards Response to NRC 980625 RAI Re Reply to NRC GL 96-06, Assurance of Equipment Operability & Containment Integrity During Design Basis Accident Conditions

Forwards Response to NRC 980625 RAI Re Reply to NRC GL 96-06, Assurance of Equipment Operability & Containment Integrity During Design Basis Accident Conditions

ML20151T572
Person / Time
Site:	Point Beach
Issue date:	09/04/1998
From:	Kaminskas V WISCONSIN ELECTRIC POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-96-06, GL-96-6, NPL-98-0718, NPL-98-718, TAC-M96852, TAC-M96853, NUDOCS 9809100061
Download: ML20151T572 (15)

Text

-. -..

~

Wisconsin Electnc POWER COMPANY Point Beach Nuclear Plant (920) 755-2321 6610 Nuclear Rd., Two Rivers. WI 54241 NPL 98-0718 10 CFR 50.4 September 4,1998 U.S. NUCLEAR REGULATORY COMMISSION Document Control Desk Mail Station PI-137 Washington, DC 20555 Ladies / Gentlemen:

DOCKETS 50-266 AND 50-301 11EPLY TO REOUEST FOR ADDITIONAL INFORM ATION TO GENERIC LETTER 96-06. " ASSURANCE OF EOUIPMENT OPERABILITY AND CONTAINMENT INTEGRITY DURING DESIGN BASIS ACCIDENT CONDITIONS" POINT BEACH NITCLEAR PLANT. UNITS 1 AND 2-NE C TAC NOS M96852 AND M96853 The NRC staffissued Generic Letter (GL) 96-06 on September 30,1996. Wisconsin Electric Power Company (WEPCO) provided its assessment of the waterhammer and two-phase flow issues for the Point Beach Nuclear Plant (PBNP) in letters dated January 28, June 25, and December 18,1997, and related submittals dated September 9, September 30, and October 30,1996. In a letter to WEPCO dated June 25, 1998, the NRC requested additional information to complete their review of WEPCO's GL 96-06 submittals. Included as Attachment A to this letter is WEPCO's response to the NRC Request for Additional Information (RAI). As suggested in the RAI, our replies make significant reference to our previous submittals which address the staff questions.

The RAI is concerned with follow-up information on GL 96-06 issues of waterhammer and two-phase flow.

To a large extent, our attached reply provides clarification and amplification of previously-transmitted information and supplements our previous responses wit new information manifest in recent, ongoing i

evaluations. It should be noted that WEPCO is participatmg in the EPRl/ Industry project to develop a utility guidance document to address industry wide NRC RAls on waterhammer issues. The end result of this project, the utility guidance document, is scheduled to be issued by July 15,1999. As indicated in Attachment A, WEPCO will defer response on some of the RAls until after completion of the EPRI project and issuance of the utility guidance document.

Please contact us if you have further questions on this issue.

Since -ly,

/

q,-

/

/#fM4 Subscribed and sworn before me on 6.

Vito A. Kaminskas this @

day of6ahmA-f 1998.

Regul Services & Licensing 2- '

[WMkd 4/

Notary Public, stSte of Wisconsin Attachments My Commission expires F

• 11 %0L cc:

- NRC Resident Inspector NRC Project Manager NRC Regional Administrator PSCW 9809100061 980904

^

PDR ADOCK 05000266 P

PDR p

.y g g,

11

. Attachment A to NPL 98-0718 l

WEPCO Response to NRC RAI on GL 96-06 l

Page 1of14 The following is WEPCO's response to the subject NRC RAI.

RAI Item 1:

Ifa methodology other than that discussed in NUREG/CR-5220, " Diagnosis of Condensation-Induced Waterhammer, " was used in evaluating the effects ofwaterhammer, describe this methodology in detail. Also, explain why this methodology is applicable andgives conservative results (typically accomplished ti v> ugh rigorous plant-specific modeling, testing, and analysis).

Response

Waterhammer:

A different methodology than that discussed in NUREG/CR-5220 was used. NUREG/CR-5220 provides reference material and diagnostic procedures concerning condensation-induced waterhammer in nuclear power plants. Five event-classes of condensation-induced waterhammer, which have similar phenomena and levels of damage, are defined in NUREG/CR-5220. Additionally, NUREG/CR-5220 provides case studies to illustrate the diagnostic methods and to document past experience. The majority of the examples and case studies presented in NUREG/CR-5220 deal with high temperature and high pressure systems.

The fourth case study presented in NUREG/CR-5220 has some similarities to the Service Water (SW) event considered in GL 96-06, cycept that the temperature considered in the scoping study in NUREG/CR-5220 is approximately 25% higher and the refill flow rate is much higher than those in the CFC circuits. It should be noted that no pressure boundary damage was reported for this case study.

The following two paragraphs describe the attemative methodologies used in evaluating me effects of waterhammer.

Rcrerence 2 describes a series of scaled waterhammer experiments performed over a range of conditions typical of the Point Beach Nuclear Plant (PBNP) SW system during the transient considered in GL 96-06. The experiment apparatus was constructed based on Froude number considerations and investigated the influence of void formation and steam condensation during the transient conditions. The results of these experiments demonstrate that no significant waterhammer transients were observed even with significant voiding and that peak pressures occurred during refill of the system. Additionally, the peak pressures were substantially less than those that would be calculated using standard waterhammer methodology.

Reference 3, Appendix A calculates Froude numbers for four pre-pump startup cases. Cases Al, A3, and A4 are based upon the containment post LOCA temperatures and structural heat transfer coefficients provided in the PBNP FSAR and clean CFC tubes, while varying the pump coastdown times. Case A2 is based upon the containment post LOCA temperatures and structural heat transfer coefficients 15% less than those provided in the PBNP FS AR, a fouling

. Attachment A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 l

Page 2 of14 factor of 0.001 in the CFC tubes, and a pump coastdown time of 10 seconds. For Case Al, the flow velocities correspond to a Froude number of 0.91 to 0.78. The test results presented in Reference 2 show that condensation-induced waterhammer will not occur, for the PBNP configuration, at such a high Froude number. For Case A2, the flow velocities correspond to a Froude number of 0.48 to 0.3. These are still higher than the Froude number at which condensation-induced waterhammer was detected in the Reference 2 test. The results of Cases A3 and A4 show that the Froude number is insensitive to the pump coastdown time, as long as the flow stops before the containment temperature reaches its peak value.

This information has been presented in the September 9,1996 submittal to the NRC, VPNPD-96-065. [Ref.11] Any further information will be presented after completion of the EPRI project.

RAI Item 2:

For both the waterhammer and two-phaseflow analyses, provide thefollowing information:

a. Identify any computer codes that were used in the waterhammer and two-phaseflow analyses and describe the methods used to benchmark the codesfor the specific loading conditions involved.

Response

Waterhammer:

Three computer programs were used in the waterhammer operability analysis; a FORTRAN code written specifically for this application to detennine steam generation rate, HYTRAN to determine force time histories from the dynamic transient, and PIPSYS to evaluate piping stress.

HYTRAN and PIPSYS are Sargent & Lundy (S&L) computer programs approved for general use on safety-related applications. The FORTRAN program was developed specifically for this application and was validated in accordance with the S&L QA program requirements for single use computer programs. TREMELO, which was used to predict force time histories for the design basis analysis has been benchmarked in accordance with FAI QA program by the following methods; comparison with experimental results, comparison with bounding hand calculation, and comparison with a steady state text book sample problem (subroutine XFORCE). Reference 10 discusses this validation in more detail.

Two-ohase Flow:

Three computer programs, WATER, AIRCOOL, and RELAP5, were identified and the validation v is discussed in Reference 1. Since that time we have further refined our analytic techniques and have used the TREMELO program developed by Fauske & Associates (FAI) to l

validate the methodology [Ref. 6], [Ref. 7], [Ref. 8], [Ref. 9], and. [Ref.13],. The WATER model, produced by Municipal Hydraulics Inc., which predicts steady-state single-phase flow i

r

. Attachment A to NPL 93-0718 WEPCO Response to NRC RAI on GL 96-06 Page 3 of14 distribution, has been shown to consistently predict CFC flows with respect to system pressure when the monthly checks are performed. AIRCOOL, which predicts CFC performance, was produced and benchmarked by Holtec International Corporation. RELAP5, used to study two-phase flow hydraulic effects, is the NRC's state-of-the-art transient flow and accident analysis program. TREMELO, has been benchmarked in accordance with FAI QA program by the following methods; comparison with experimental results, comparison with bounding hand calculation, and comparison with a steady state text book sample problem (subroutine XFORCE) Reference 10 discusses this validation in more detail.

b. Describe andjustif all asswnptions and inputparameters (including those used in any computer codes) such as amphfications due tofluid-structure interaction, cushioning, speed of sound, force reductions, and mesh sizes, and explain why the values selected give conservative residts. Alsoprovidejustificationfor omitting any effects that mon he relevant to the analysis (e.g., fluid-structure interaction, flow induced vibration, erosic

Response

Waterhammer:

This information will be presented after completion of the EPRI project.

Two-ohase Flow:

The fbliowing discussion addresses the key parameters and assumptions for two-phase flow.

Containment temperatures for the two-phase analysis were taken from Reference 4. Appropriate margin, (3 F for the injection phase of the LOCA and 10 F for the recirculation phase) are added as a measure of conservatism. CFC coils are assumed to have a fouling factor of 0.0001 BTU /Hr z

- fi. This fouling is much less than any field measurement has exhibited. Results of the RELAP analysis [Ref 5] show no significant cyclical variations in pressure or flows about the steady-state values. This indicates that flow-induced vibration due to periodic bubble formation and collapse is insignificant, if not completely absent. Two-phase flow potentially occurs only during a Design Basis Accident (DBA) event and then only for a period of hours. Therefore, erosion effects, which are typically long-term, can be considered insignificant for this analysis.

c. Provide a detailed description ofthe " worst case" scenariosfor waterhammer and two-phase ficw, taking into consideration the complete range ofevent possibilities, system configurations, andparameters. For example, all waterhammer types and water slug scenarios should be considered, as well as temperatures, pressures, flow rates, load combinations, andpotential componentfailures. Additional considerationsfor two-phaseflow include:

the effects ofvoidfraction onflow balance and heat transfer; the consequences ofsteamformation, transport, and accamulation;

Attachment A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 Page 4 of 14 cavitation, resonance, andfatigue effects; and erosion con.siderations

Response

Waterhammer:

Waterhammers were considered during both phases of the transient, the pre-pump start phase and the refill phase. Reference 2 indicated no evidence of condensate-induced waterhammer for the Froude numbers predicted in the pre-pump start phase. The following bounding assumptions are made in determining waterhammer effects in the refill phase; bounding the maximum flow rate to the coolers by assuming half of the total SW flow will go to the upper CFCs, neglecting the flow resistance through the CFC outlet throttle valves, and assuming zero psia backpressure throughout the uansient. All of these assumptions tend to maximize the impact forces of the we':rhammer during the refill phase. Any further information, such as a discussion of various types of waterhammer and water slug scenarios identified in NUREG/CR-5220, will be presented after completion of the EPRI project.

Two-phase Flow:

The SW System consists of 6 parallel pumps feeding a continuous flow ring header. Each of the plants two Safety Injection (SI) trains is associated with three pumps. There are isolation valves in this header so that it has the potential (for a limited time period) to have the normal supply flow path intenupted and as a result causing some components to be fed through a more flow-resistant supply path. In the unlimited operating condition there is no interruption of flow in this header. The SW System is currently analyzed for all bounding scenarios and two-phase flow downstream of the CFCs is considered in each one. Both injection phase and recirculation phase are analyzed for each configuration. CFC heat loads are detemlined by the post-LOCA containment response curves. The recirculation phase includes higher Component Cooling Water (CCW) flow but als3 includes more isolation of branch headers and reduced containment temperatures than the injection phase. These configurations include all combinations of allowable SW continuous flow header isolations (including no isolation), as well oc differing numbers of operating SW pumps. The scenaries are further analyzed with the CFC outlet throttle valves at both extremes of their allowable range. The results of the analyses of these configurations can be found in References 6,7,8, and 9. The worst configurations from a CFC perspective were determined from thece analyses and are detailed below.

Scenario #1: This is the most limiting scenario with respect to CFC heat removal. It occurs during the injection phase and includes an isolation of one main flow path strainer so that all flow is directed through the other strainer. Five SW, umps are assumed to be operating; however the non-accident unit CFCs are analyzed in the maximum flow position. This includes the outlet accident-flow MOVs being opened (for testing or maintenance). In addition, the CFC throttle valves are assumed to be at the low flow throttle position. No branch headers are l

l l

l

KAttachment A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 Page S of14 assumed to be isolated, the CFCs are at the maximum allowable fouling, and the SW temperature l

is at the maximum design temperature. This condition requires the plant to be in a limiting condition for operation (LCO) for 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

Scenario #2: This is the most limiting scenario with respect to two-phase flow in the CFC return piping. It occurs during the injection phase. Three SW pumps are assumed to be operating i

because a failure of one Safety Injection Train has been postulated, thus disabling the other three pumps. In addition, the CFC throttle valves are assumed to be at the high flow throttle position.

Two of the five branch headers are assumed to be isolated, the CFCs are at the minimum allowable fouling, and the SW temperature is at the maximum design temperature. This scenario results in the lowest system pressure and the lowest flow resistance in the CFC piping which minimizes the pressure in the CFC downstream piping. This condition can occur when the plant has not entered an LCO.

In both scenarios it was determined that there was no two-phase flow in the CFCs and that there would be two-phase flow in the CFC piping downstream of the outlet throttle valve, but each CFC was still able to remove the design basis heat load.

The effects of void fraction on flow bhnee and heat transfer on two-phase flow were taken into j

account in the methodology for determining adequate steady-state tu cephase flow by the confimiing TREMELO analysis for that methrdology. [Ref.13] 1he consequences of steam formation, transport, and accumulatio 1in the steady-state two-phase f!W are Aemed to be bounded by any transient waterhammer loads. Cavitation, resonance, fatige.:ffects, and erosion considerations were reviewed using Reference 12 and are not included in the analysis because of the short time frame (several hours) that the piping would be exposed to the two-phase flow potential, as well as the absence of cyclical variations in the pressures and flows during this period.

d. Confirm that the analyses included a completefailure modes and effects analysis (FMEA)for all components (inchiding electrical andpneumaticfailures) that could impact performance of the cooling water system and confirm that the FMEA is documented and availablefor review, or explain why a complete andfidly documented FMEA was notperformed.

Response

- Waterhammer:

A complete FMEA was not perfcnned. The waterhammer forces are dependent on refill rate.

Refill rate is dependent on the number of SW pumps nmning and the amount of competing loads.

The system design is such that operation of any relevant active component, i.e. pump starting or valve repositioning, tends to maximize flow to the CFCs and therefore refill rate. Because waterhammer loads tend to increase with increasing refill rates, the assumption of no failures is conservative. Any further information will be presented afler completion of the EPRI project.

. Attachment A to NPL 98-0718 i

l WEPCO Response to NRC RAI on GL 96-06 Page 6 of14 Two-nhase Flow:

A complete FMEA was not performed. However, the failure of a complete electrical train of safety injection, which is the basis for LOCA analysis, was assumed. Two parameters affect l

steady state two-phase flow in the SW System. The first is the amount of SW Gow through the CFCs. The second is the amount of heat input from containment atmosphere to the SW flow.

The degree of two-phase Dow increases with increased heat transfer. Any degradation in the CFC performance will lessen the impact of two-phase Dow. The amount of SW Dow is dependent on the CFC piping configuration (including valve position), the supply header pressure and the return header pressure. The supply header pressure is dependent on the overall system resistance and the number of SW pumps running. The only active components required to operate to reduce the effects of two phase flow for this limiting scenario are the SW pumps and the branch header isolation valves which divert flow from the CFCs. A single failure of an entire SI train is assumed so that only three SW pumps are assumed to run and three branch header isolation valves are assumed to remain open. The failure of an additional active component, one of the two CFC outlet MOVs, to open, increases CFC outlet pressure and thus provides more margin before two-phase Dow occurs in the CFCs. Its failure was not assumed.

c. Explain andjustify all uses of "engineeringjudgment ".

Response

Waterhammer:

This information will be presented after completion of the EPRI project.

Two-phase Flow:

Any piping interactions are assumed to be bounded by the waterhammer analyses. The location (outside containment and downstream of the CFC outlet throttle valves) and stable pressure and Dow profile (predicted by RELAP) are indicative of more stable conditions than the dynamic effects of waterhammer.

RAI Item 3:

Determine the uncertainty in the waterhammer and two-phaseflow analyses, explain how the uncertainty was determined, and how it was accountedfor in the analyses to assure conservative results.

Response

Waterhammer:

The waterhammer analysis was performed using conservative assumptions (See RAT Item 2.c).

Any further information will be presented after completion of the EPRI project.

l

. Attachment A to NPL 98-0718 WEPCO Respense to NRC RAI on GL 96-06 Page 7 of14 Two-phase Flow:

WEPCO addressed uncertainties in the two-phase flow analysis by a codoination of conservative assumptions and analytical techniques which represented mutually exclusive plant conditions. In addition, the following uncertainties have been accounted for in the analyses: IST to ensure pump performance is in accordance with the analysis includes both temperature and Dow uncertainties, SW Dow to the CCW heat exchangers during the recirculation phase of the LOCA includes instrw lent uncertainty, the SW inlet temperature includes instrument uncertainty when verifying that the system is operating within its design basis.

The CFC flow paths have two points of variable resistance in them. Each CFC has its own outlet throttle valve which is verified each month to be within the allowable throttle positions determined by the analysis. This position is checked by setting up the propet flow configuration and verifying the flow through each CFC as a function of system pressure. The valve is typically set in the middle of the allowable band. This throttle position accounts for the instrument uncertainties so that the allowable operational band in the field is less than the band allowed by analysis. Ir addition, the assumed resistance in the analysis is dependent on the parameter being analyzed. Each plant configuration is analyzed twice for CFC considerations. When analyzing the CFCs for minimum heat input, the highest fouling factor and the highest throttle valve position is assumed. Even though the valve is physically in the same position, when analyzing for two-phase flow the valve is assumed to be in its least resistant position and the same CFC is assumed to be at its lowest fouling factor.

The CFCs also have two parallel Motor-Operated Valves (MOVs) that, when open, increase flow thrugh all CFCs simultaneously. Each one of these valves is powered by one SI train and open on an,il signal. In the scenario discussed, one SI train was assumed to fail (single failure). For conservatism, it was assumed that both MOVs would open even though the failure of one SI train would not only prevent the three SW pumps from starting but would also prevent one of the MOVs from opening. This condition could be entered if one unit only was in a SW LCO.

RAI Item 4:

Conprm that the waterhammer and two-phasepow loading conditions do not exceed any design specylcations or recommended service conditionsfor the piping system and components,

including those stated by equipment vendors; and conprm that the system will continue to perform its design-basisfunctions as assumed in the sajl y analysis reportfor thejacility and that the containment isolation valves will remain operable.

l

Attachment A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 Page 8 of14

Response

Waterhammer:

Per Reference 11, the SW system was determined to be operable. The subsequent analyses tabulated in the response to Question 6 were performed to determine the acceptability of the SW i

system with respect to the allowable design loads of the piping using dynamic loads generated by TREMELO. The resultant modifications will, when complete, assure compliance with design allowable loads in the FSAR. Any further information will be presented after completion of the j

EPRI project.

Two-ohase Flow:

It is our conclusion that any piping loads experienced because of the steady state two phase flow are much less than the bounding, transient loads. In addition, because the potential two phase flow occurs downstream of the CFCs and outside containment, a breach of this piping would not affect flow to the CFCs and would not represent a potential contact point between the containment atmosphere and the SW System and hence a potential release path for radioactivity 6

The design basis for the CFCs is that they each be capable ofremoving 37.5 x 10 BTU /hr from the containment atmosphere under c mtainment design conditions and that there is no two-phase -

flow in the CFCs. These conditions tre still met.

RAI Item 5:

Provide a simphjied diagram ofthe system, showing major components, active components, relative elevations, lengths ofpiping runs, and the location ofany onfices andflow restrictions.

Response

These figures are provided at the end of this attachment.

RAI Item 6:

Describe in detailanyplant modification orprocedure changes that have been made or are planned to be made to resolve the waterhammer and two-phaseflow issues.

. Attachment A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 Page 9 of 14 4

Response

lVaterhammer:

The analyses referred to in the response to Question 4, their resultant piping support modifications, and the installation status of those modifications is tabulated below.

Unit 1 Inside Containment Unit 2 Inside Containment Analysis Mod l/

Installed Analysis Mod #

Installed WE-100121 Rev 1 96-064A Yes WE-200090 Rev i 96-064C No WE-100123 Rev 1 96-064A Yes WE-200091 Rev 1 96-064C No WE 100125 Rev 1 96-064A Yes WE-200092 Rev 1 96-064C No WF-100126 Rev 1 96-064A Yes WE-200093 Rev 1 96-064C No WE-100129 Rev 1 96-064A Yes WE-200094 Rev 1 96-064C No WE-100131 Rev i 96-064A Yes WE-200095 Rev 1 96-064C No WE-100132 Rev 1 96-064A Yes WE 200096 Rev 1 96-064C No WE-200097 Rev 1 96-064C No

,a Unit 1 Outside Containment Unit 2 Outside Containment Analysis Mod #

Installed Analysis Mod #

Installed WE-300035 Rev i 96-064B Yes WE-300044 Rev 1 96-054D No Two-ohace Flow:

Plant procedure changes have been implemented to assure adequate flow to the CFCs to provide design basis heat removal and adequate pressure to prevent two-phase flow in the CFCs.

EOP-1.3 was changed to ensure enough SW demands were isolated when going into the recirculation phase of a LOCA, OI-70 (operating instructions for the SW system),was changed to ensure that the SW system lineup is maintained in accordan ce with the existing analysis OI-71 (operating instructions for the CCW system), was changed to ensure that the SW system lineup is maintained in accordance with the existing analysis PBF-2033 (Unit 2 Turbine Hall Shift Log) was revised to preclude simultaneous timed e

blowdown from the main system strainers.

PC-43.3 (Periodic Callup for SW Strainers) was revised to ensure that only one Spent Fuel Pit Heat Exchanger is on-line at any time.

Attachment A to NPL 93-0718

. WEPCO Response to NRC RAI on GL 96-06 Page 10 of 14 IT-72 (Service Water Valves [ Quarterly]) was revised to ensure that only one Spent Fuel Pit Heat Exchanger is on-line at any time.

IST IT 007C, (P-32C SW Pump Inservice Testing Criteria) was revised to ensure that pump performance exceeded that used in the analysis.

I

~

. Attachment A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 Page 11of14 References

'1, WE letter to NRC, September 30,1996 letter, VPNPD-96-080 1

2. FAI/96-75, " Evaluation ofPossible Waterhammer Loads in the Service Water System for DBA Conditions," dated September,1996 j

3. S&L Calculation, M-09334-186.SW," Operability. Assessment for Transient Conditions in Point Beach Nuclear Plant Service Water System During a Coincidental Loss of Coolant j

Accident and Loss of Offsite Power," dated September 9,1996

4. Westinghouse, Calculation, NSD-SAE-ESI-97-302," Wisconsin Electric Power Company, Point Beach Units 1 & 2, Containment Analysis Assuming Reduced Fan Cooler Performance," transmitted May 29,1997.

5. S&L Calculation, M-09334-195.SW,"RELAPS Modeling of Component Fan Cooler Service Water Return Lines," dated, September 27,1996

6. WE Calculation,96-0117, Rev 2, " Service Water Model Runs: Three Pump / Injection Phase,"

dated July 7,1998

7. WE Calculation,95-0119, Rev 3, " Service Water Model Runs: Three Pump / Recirculation Phase," dated July 7,1998

8. WE Calculation,97-0054, Rev 2," Service Water System, Limiting Condition for Operation Injection Phase," dated July 7,1998 i

9. WE Calculation,97-0126, Rev 2, " Service Water System, Limiting Condition for Operation Recirculation Phase," dated July 7,1998

10. FAI/97-60 Rev 1," Point Beach Containment Fan Cooler Analysis in Response to NRC Generic Letter 96-06," dated August 8,1997

11. WE letter to NRC, Septernber 9,1996 letter, VPNPD-96-065

12. NUREG/CR - 6031, " Cavitation Guide for Control Valves," J. Paul Tullis, dated April 1993

13. FAI/98-55, " Methodology for Determining Adequate Containment Fan Cooler (CFC) Flow,"

Rev 1, dated 6/15/98

.- -.~. -,

4

. Attachment A to NPL 98 0718 WEPCO Response to NRC RAI on GL 96-06 Page 12 of14 The following is a simplified schematic of the SW System showing the relative positions of the SW pumps, the CFCs and the branch headers. The "A",."B", "C", and "D" CFCs are denoted on j

the following pages as 1HX-15A,1HX-15B, where the prefix "1"is the unit number and the suffix "A" is the CFC identifier.

/\\

/\\

/\\

/\\

/\\ "D" CFC Wa r "A" CFC "C" CFC "D" CFC U2 CFC U2 CFC U2 Turbine Hall Radweste l

s CCW

' Aux FW PP s

Ps CCW Aux FW PP SA Compressor

/

S/

Emergency DG Spent Fuel Pit x.yg, gj X-Tle I

N /\\

Aux FW PP/\\

IA Compressor l

SA Compressor CCW Aux FW PP Emergency DG l

T T

I lStralner l

U1CFC m

Service Old/

U1 Turbine Hall "A"CFC "C" CFC Aux Bld Vent "D" CFC "b" CFC g/

gj

%/

S/

J-

~-.

~. Attaciunent A to NPL 98-0718 WEPCO Response to NRC RAI on GL 96-06 * *,,.

Page 13 of14 s

t

,/

s

/

\\

j l

\\

I 1 HX-15 A

- 85 o

I o

I o

- 80 j

j o

e o

o _

- 75 I

I 2'2f' 12/"

3" 2

- 70 3

() ()

3

- 65 I

El h2l u

i

- 60 s.

I gl

- 55 I

8" 8"d l

- 50 I

I I

E - M,5 U

I

~

N 5

=

$ - 40 w

I i

- 35 l

i

- 30 l

- 25 N TO

- 20 1HX-15C l l

- 15 I

I I

l

- 10.

I l

-5 i

M-09334-186.SW, Rev. 00 Proj. No. 09334-126

-0 l

1HX-15A g e 23 g

f SHEET 1 y;p t

m,

. Attachment A to NPL 98-0718 M-09334-186.SW, Rev. 00 WEPCO Response to NRC R Al on GL 96-06 bj.No. 09334-186 Page 14 of14 Page 27 Figum 1

- 85

- 80

--75

- 70

- 65

- 60

- - 55

@d 3 - 50

! - 45

' -g 1HX-15A "i - 40 l-1HX-15C

_w 20" SW

- 35 RETURN HOR.

X h

D k

=

y a

y

- 30 X

__a X -

t f

- 25 k

I

-1HX-158

- 20 1HX-150 FROM UNIT 2 J D

'3

- 15 CFCS

- 10

/

/

UNIT.2 UNIT 1

_3 SW DISCH.

SW OISCH.

TO CW SYSTEM TO CW SYSTEM SHEET 5 y

,