ML20206P575

Thermal Analysis of Safety-Related Valves Exposed to Vogtle Electric Generating Plant Control & Auxiliary Bldg Steam Line Breaks

ML20206P575
Person / Time
Site:	Vogtle
Issue date:	06/25/1986
From:	WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
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ML20206P559	List: ML20206P555 ML20206P575
References
NUDOCS 8607020159
Download: ML20206P575 (17)

Text

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ATTACHMENT 2 l

{

HESTINGHOUSE PROPRIETARY CLASS 3 THERMAL ANALYSIS OF SAFETY RELATED VALVES EXPOSED TO VEGP CONTROL AND AUXILIARY BUILDING STEAM LINE BREAKS hbh kDO $4 E

WESTINGHOUSE PROPRIETARY CLASS 3

. iABLEOFCONTENTS Section Title Page 1.0 BACKGROUNO 2 2.0 PURPOSE 2 3.0 HEAT TRANSFER MODEL 2 4.0 VALVE DESCRIPTION AND THERMAL RESPONSE 9 5.0 RESULTS 14 6.0 MARGIN 14

7.0 CONCLUSION

S 15

8.0 REFERENCES

16 PE90E/20E/860520:12 1

, WESTZNGHOUSE PROPRIETARY CLASS 3  ;

c

1.0 BACKGROUND

Vogtle Electric Generating Plant (VEGP) has several Class IE valve assemblies, located in the Control and Auxiliary Buildings, which can be exposed to  ;

superheated steam resulting from various postulated main stem line breaks (MSLB). Ambient temperatures resulting from these MSLB's can reach maximum values as high as 400*F. The superheated steam temperature profiles are based on Westinghouse generic mass and energy release data and on a VEGP-specific subcompartment analysis performed by Bechtel. Four specific valve types - the main steam isolation valves (MSIV), main steam isolation valve bypass valves, the auxiliary feedwater pump discharge valves, and the atmosphere steam dump valves (SDV) - have been designated by Bechtel as safety related, Class IE valves which may be subjected to the postulated MSLB's. While all the above valve types have successfully completed environmental qualification test programs, the maximum MSLB environmental temperatures achieved during these qualification tests did not envelop the maximum MSLB environmental temperature postulated in 'the VEGP Control and Auxiliary Buildings. Based on this situation and in order to demonstrate qualification of the specific equipment at VEGP under these conditions, it is necessary to demonstrate that the actual safety related component temperature Lchieved under the VEGP MSLB's is less than the component temperature reached in the qualification te: ting program.

2.0 PURPOSE The purpose of the analysis is to verify the environmental qualification of various safety related, Class lE valve components identified herein by demonstrating that the temperatures actually achieved by these components during the postulated VEGP MSLB's are less than the temperatures achieved by these components during their respective qualification tests.

3.0 HEAT TRANSFER MODEL 3.1 Component Thermal Response The thermal response of a component exposed to an MSLB can be characterized by the heat transfer mechanism occurring at a given point in time. The heat transfer mechanisms are as folicws:

PE90E/20E/860520:12 2

WESTINGHOUSE PROPRIETARY CLASS 3

a. The component temperature rises rapidly during the initial temperature rise from ambient to peak until the component reaches saturation temperature corresponding to ambient pressure.

_ Initially, the steam impinging the component condenses and gives up its heat to the cooler component. The heat transfer rate of condensing steam is very high and the condensing heat transfer coefficient is in the order of 1,000 - 20,000 Stu/hr - sq ft *F (Reference 1). The temperature of the component rises rapidly at a rate dependent upon the steam temperature, environment pressure, the surface area and specific heat of the component, and the mass flow rate of the steam.

b. Once the component reaches saturation temperature, the temperature stabilizes. The component remains at saturation temperature until the water which condensed on the component during the initial phase changes from saturated liquid to saturated vapor. The amount of time at this plateau is dependent upon the mass of water condensed on the component, the surface area of the component, environment pressure, and the temperature and mass flow rate of steam at the component.

c. After the water which condensed on the component evaporates, the temperature of the component begins to rise again. The heat transfer mechanism occurring during this phase is one of forced convection and depends primarily upon the mass and surface area of the component, the velocity of the steam, the temperature of the steam, and the initial temperature of the component. The heat transfer mechanism during the forced convection stage is not as efficient as the mechanism in a. above and the heat transfer coefficient is of the order of 5-50 Btu /hr-sq ft*F (Reference 1).

The thermal response of the subject components exposed to the VEGP Control Building or Auxillary Building MSLB temperature profiles will reflect the above heat transfer mechanisms. The component temperature will rise very rapidly to 221oF (saturated temperature at 3 psig), and then the component will remain at saturated PE90E/20E/860520:12 3

, HESTINGHOUSE PROPRIETARY CLASS 3

. temperature until the water which condensed on the valve changes state from saturated liquid to saturated vapor. After " drying off,"

the component temperature will rise based on the forced convection

_ heat transfer mechanism.

3.2 Heat Transfer Methodology Westinghouse has developed a heat transfer model that predicts the temperature response of a component that is exposed to a steam line break in the Vogtle Control Building and Auxiliary Building. This model is based on a previous model that was developed for an ASCO Model NP8316 solenoid valve exposed to an in-containment LOCA/MSLB (Reference 2) and on empirical forced convection heat transfer correlations. The Reference 2 model was based on actual thcrmocouple data from steam chamber tests at the Franklin Research Center, (FRC) (Reference 3).

3.2.1 In Re'ference 2, the initial valve heatup from normal ambient temperature to saturated temperature was modeled by calculating the rate of increase in the valve internal energy. This rate can be ~

expressed by the following equation:

Q - cmaT/t (Equation 1) where:

Q - Rate of increaae of Valve Internal Energy (Stu/sec) c - Specific Heat of Valve Material - Brass (Btu /lb *F) m - Weight of Valve (lbs)

AT - Saturation Temperature - Initial Temperature (aF) t - Time required for initial heat-up (sec)

From the FRC test results, the rate of increase of valve internal energy was calculated to be:

Q = 4.29 Btu /sec (Reference 2).

PE!0E/20E/860520:12 4

HESTINGHOUSE PROPRIETARY CLASS 3 For the VEGP MSLB, the time required for the initial heat-up can be determined by using the Q calculated from the FRC data and solving Equation 1 for time (t). Equation 1 yield' s a conservative estimate of the initial heat-up time for VEGP since the pressure and MSLB temperature profile for VEGP are less severe than the FRC profile.

3.2.2 The time that the component remains at saturated temperature was modeled in Reference 2 by the following expression:

mah,- mh3 at (Equation 2) where m - Mass of water on component (1bs)

Ah, - Enthalpy of vaporization of water at saturated temperature (Stu/lb)

- Mass flowrate of steam icpinging the component (lb/hr) h s

- Enthalpy of the superheated steam (Btu /lb) at - Time at saturated temperature (hr)

From the FRC test results (Reference 2):

y = 0.71 lbs/hr m = 0.021 lbs of water For a component exposed to a steam line break in the Vogtle Control or Auxiliary Building:

m - ^ component),

1. (#

8316 PE90E/20E/860520:12 5 L

WESTINGHOUSE PROPRIETARY CLASS 3 where A

component - Surface Area of the component A

8316

= Surface Area of ASCO 8316 valve m, - Mass of water on component (lb) m - 0.014 lbs of water ah, = 965 Btu /lb (Saturated w.ter at 3 psig) h 3

- 1191 8tu/lb (Superheated steam at 300*F) 3.2.3 The component temeprature departs from saturation temperature after the component has " dried off." If the temperature gradients within the component are conservatively assumed to be negligible (i.e., the interior component temperature is equal to the surface temperature)-

the component temperature at any given point in time can be predicted by the following equation (Reference 4):

T-T $

hA 5

in t (Equation 3)

T i

T " mc s

where T - Component Temperature at Time t (*F)

T = Superheated Steam Temperature (*F) s Tg - Initial Component Temperature (*F) h - Forced Convection Average Heat Transfer Coeff.icient (Btu /hr-ft 'F)

A = Surface Area of Component (ft2) 3 m - Weight of Component (lbs) c - Specific Heat of Component Material - (Btu /lb *F) t - Time (hrs)

PE90E/20E/860520:12 6

WESTINGHOUSE PROPRIETARY CLASS 3 The average forced convection heat transfer coefficient, h, is a function of the geometry of the component and the velocity'and temperature of the superheated steam. Since the geometry of the components in question vary (flat plate, cube, cylinder, sphere, and combinations of these shapes), heat transfer coefficients need to be calculated for all these shapes.

The heat transfer correlations for the various geometries are:

A. Cylinder (Reference 5)

Nu - - (0.4 Re0.5 + .06 Re0.67) Pr0.4 )0.25 (Equation 4) where Nu - Nusselt's Number

- Hydraulic Diameter (ft)

D Re - Reynold's Number Re = ;V - Steam Velocity (ft/sec) 0 - Hydraulic Diameter (ft) 2 v - Kinematic Viscosity (ft /sec)

Pr - Prandtl Number of Steam p

3

- Steam Viscosity at Component Surface (Ib/ft-sec)

. Free Stream Steam Viscosity (Ib/ft-sec) k - Thermal Conductivity of Steam (Stu/hr-ft *F)

8. Sphere (Reference 5)

Nu - - 2+ (0.4 Re0.5 + .06 Re0 .67 ) Pr0.4 )0.25 (Equation 5)

C. Cube (Reference 6) 0 o Nu - .102 Re .675 Pr .33 (Equation 6) 4 PE90E/20E/860520:12 7 k

WESTINGHOUSE PROPRKETARY CLASS 3 D. Flat Plate -(Reference 5) 2 Nu = h .20 Re /3 (Equation 7) 3.2.4 Utilizing the thermal response model discussed above and the VEGP specific MSLB temperature and steam velocity proflies provided by Bechtel, Westinghouse has determined the maximum temperature reached by safety-related, Class IE valve components located in the Control and Auxiliary Buildings at VEGP.

3.2.4.1 Bechtel provided MSLB profiles for 7 separate cases of MSLB conditions in both the Control and Auxiliary Buildings. Detailed evaluations of all these cases revealed that the cases in the Control Building were more severe than those in the Auxiliary Building. Of the cases (V01, V02, V07, V09, VIO, VII and V15) in the Control Building, three cases (V01, V02, Vil ) included the most severe conditions (highest peak temperature and longest total time above qualification test peak temperature). Cases V01, V02 and VII in the Control Building were therefore analyzed to represent and envelope all the other cases at VEGP for the MSLB condition in the Control and Auxiliary Buildings.

PE90E/20E/860520:12 8

HESTINGHOUSE PROPRIETARY CLASS 3

. 4.0 VALVE DESCRIPTION AND THERMAL RESPONSE Bechtel has identified'four valve types located in the VEGP Control and Auxiliary _ Building which must perform a safety function during or after the postulated MSLB. Westinghouse has reviewed each of these valve designs and performed a thermal analysis, as described in Section 3.0, to determine the worst case temperature reached by any of the valve components critical t *he safety function of the valve. This temperature was then compared to the previously established qualification temperature for the valve / valve component. Table 1 provides a summary of the results of the analysis of each valve design and critical component. The specific results of each analysis for each valve type / valve component are discussed below.

4.1 Main Steam Isolation Valve Bypass Valves The MSIV Bypass Valve is described on Fisher Controls Orawing 50B0608 Revision B. The valve air actuator assembly has four NAMCO Model EA-180 series limit switches and one ASCO Model NP8320 series solenoid valve which -

are critical to the safety function of the MSIV Bypass Valve. Other degradable, non-metallic components such as the actuator diaphragm and 0-ring are not critical to the safety function of the MSIV Bypass Valve. The MSIV Bypass Valve is located in Node 4 of the Control Building.

4.1.1 The NAMC0 Model EA-180 series limit switches weigh 4.5 lbs, have brass bodies and are cubic in shape with a total area of 0.47 square feet. Utilizing the methodology described in Sections 3.2.1 and 3.2.2 the time for the switches to reach saturation temperature is 11 seconds and the time at saturation temperature is 77 seconds.

Examining Cases V01, V02 and Vil for the forced convection heat transfer region and utilizing the methodology of Section 3.2.3, a maximum limit switch temperature of 310*F is determined.

Reference 7 lists a qualification temperature of 340*F for this model limit switch.

I PE90E/20E/860520:12 9

WESTIhGHOUSE PROPRIETARY CLASS 3 4.1.2 The ASCO Model NP 8320 series solenoid valves weigh 1.8 lbs, have brass bodies and are of a complex shape with a total surface area of 0.28 square f'eet. Since the shape of the solenoid valve is complex,

.the valve was analyzed as a sphere and cylinder and the worst case result (sphere) was used to compare to the existing qualification test conditions. Utilizing the methodology described in Sections 3.2.1 and 3.2.2 the time for the solenoid valve to reach saturation temperature is 4 seconds and the time at saturation temperature is 46 seconds. Examining Cases V01, V02 and Vil for the forced convection heat transfer region and utilizing the methodology of Section 3.2.3, a maximum solenoid valve temperature of 329'F is determined. Reference 8 lists a qualification temperature of 346*F for this model solenoid valve.

4.2 Auxiliary Feedwater Pump Discharge (AFPD) Valves The AFPD Valves are described in Fisher Controls Drawings 57A5347 Revision B and 57A5345 Revision B. The valves are motor operated valves with a

• Limitorque motor operator Model SB-00-10 and Model S8-00-15. The Limitorque motor operator assemblies are critical to the safety function of the AFPD Valve. No other degradable parts of the valve, critical to the valve safety function exist. The AFPD Valve is located in Node 3 of the Control Butiding.

4.2.1 The Limitorque 58-00-10 motor operator is slightly smaller in weight than the S8-00-15 operator due to the smaller motor size and thus will be the worst case for analysis. The S8-00-10 opJrator weighs 250 lbs, has a cast iron body and is a complex shape, with a total surface area of 9.3 square feet. Since the majority of the mass and surface area of the Limitorque operator is in a cubic shape, this shape was used for the forced convection portion of the analysis.

Utilizing the methodology of Section 3.2.1 and the actual test results of Reference 9, the time for heatup to saturation temperature is 113 seconds. In the case of Limitorque the Reference 9 testing documents a superheated steam test wherein the Limitorque operator was exposed to numerous superheated steam transients at temperatures as high as 385'F at 66 psig. The actual temperature of PE90E/20E/860520:12 10

HESTINGHOUSE PROPRIETARY CLASS 3

' the operator was measured during this test and thermocouple data indicated that the operator never rose above the saturation temperature (314*F) throughout the whole test. Comparing the total

-heat input to the operator after the operator has reached saturation temperature during the Reference 9 test to the same total heat input after reaching saturation temperature during the worst case VEGP superheat condition, reveals that more total heat above saturation temperature was available during the Reference 9 test. Thus it can be concluded, since the operator never rose above saturation temperature during the Reference 9 test, that the operator would never rise above the saturation temperature of 221*F at VEGP. Even assuming the operator does rise above saturation temperature and utilizing the methodology of Section 3.2.3, the maximum temperature of the operator would be 255*F. Reference 10 lists a qualification temperature of 310*F for this model Limitorque operator.

4.3 Atmosphere S' team Dump Valves (PORV)

The PORV is described on Paul Monroe Hydraulics, Inc., drawings PD 86620 Revision C, PD 86297 Revision E. PD 86642 Revision E and-PD 86905 Revision D.

The parts list for the PORV is given in PA 86285 Revision E. While the PORV actuator is a complicated hydraulic / pneumatic assembly of smaller valves, pumps, piping, fittings, etc., the entire PORV is enclosed in a cubic-shaped shroud made of Hetron 197P Polyester Resin. The shroud consists of a series of 1/2 inch thick platec with the largest plate having a surface area of 6.3 square feet and a weight of 19.7 lbs. Since this shroud (along with the stainless steel base) totally enclose the PORV actuator, it is the shroud which will heat up first as a direct result of the superheated steam. While the shroud plates do not form a hermetic seal around the PORV actuator internals and will allow steam to penetrate inside the shroud, the velocity of this superheated steam which penetrates the shroud will be so small that forced convection heat transfer will be minimal. Thus the worst case temperature rise for the PORV actuator can be determined by analyzing the total heatup of the shroud plates themselves. The PORV is located in Node 2 of the Control Butlding.

PE90E/20E/860520:12 11

WESTINGHOUSE PROPRIETARY CLASS 3 4.3.1 Utilizing the methodology described in Section 3.2.1, the time for the shroud plate to reach saturation' temperature is 232 seconds.

The time at saturation temperature was conservatively neglected for this case. Utilizing the methodology described in Section 3.2.3 and examining cases V01, V02 and Vil for the forced convection region, a maximum shroud temperature of 272*F is determined. Reference 11 Ilsts a qualification temperature of 350*F for the PORV actuator assembly.

4.3.2 Even though the PORV actuator is totally enclosed in the shroud as described above, the maximum temperature of the 4-way Keane solenoid valve located within the shroud was determined. The Keane solenoid valve was chosen since it has the smallest mass of those assemblies critical to the operation of the PORV actuator. 0-rings and gaskets which are also critical to the operation of the PORV actuator, while smaller themselves in mass than the Keane solenoid valve, are enclosed in surrounding masses, which as an assembly, are heavier than the Keane solenoid valve. The Keane solenoid valve was conservatively analyzed as though the shroud did not exist under conditions of direct exposure to superheated steam. Utilizing the methodology described in Sections 3.2.1 and 3.2.2, the time for the Keane valve to reach saturation temperature is 41 seconds and the time at saturation temperature is 173 seconds. Examining Cases V01, V02 and V11 for the forced convection heat transfer region and utilizing the methodology of Section 3.2.3, a maximum Keane solenoid valve temperature of 286*F 15 determined. Reference 11 lists a qualification temperature of 350*F for the PORV actuator assembly.

4.4 Main Steam Isolation Valve (MSIV)

The HSIV is described on Rockwell International Drawing PD-155159 Revision E.

The MSIV actuator assembly is a gas hydraulic design. The actuator has four 3-way Keane solenoid valves and four NAMCO Model EA-180 series limit switches which are critical to the safety function of the MSIV. Other degradable, soft parts, e.g., 0-rings and gaskets while smaller in mass than the solenoid valves and limit switches and critical to the safety function of the MSIV.

PE90E/20E/860520:12 12 .

HESTINGHOUSE PROPRIETARY CLASS 3 are enclosed in.much larger mass assemblies than the solenoid valves and limit switches. These parts will thus not heat up to as high a temperature as the solenoid valves and limit switches. Other critical subassemblies, e.g., the hemisphere, are much larger in mass than the solenoid valves and limit switches and are attached to the massive actuator. structure so as to become, from a thermal standpoint, part of that superstructure.' Thus these parts also will not heat up to as high a temperature as the solenoid valves and limit switches. The analysis thus considered the Keane solenoid valves and the NAMCO limit switches as the most conservative cases. The MSIV is located in Node 4 of the Control Building.

4.4.1 The analysis of the NAMCO Model EA-180 series limit switches has been discussed in Section 4.1.1. The maximum temperature reached by these switches is 310*F. Reference 7 lists a qualification temperature of 340*F for this model limit switches.

4.4.2 The Keane 3-way model solenoid valve weighs 6 lbs, has a steel body and is a combination of a cubic and cylindrical shape with a total surface area of .45 square feet. Utilizing the methodology described in Sections 3.2.1 and 3.2.2 the time for the Keane valve to reach saturation temperature is 15 seconds and the time at saturation temperature is 76 seconds. Examining Cases V01, V02 and Vll for the forced convection heat transfer region and utilizing the methodology described in Section 3.2.3, a maximum valve temperature of 309'F is determined. Reference 12 lists a qualification temperature of 355'F for the Keane solenold valves on the MSIV.

5.0 RESULTS Table 1 presents the results of the thermal analysis discussed herein for the critical components on all four valve types for Cases V01, V02 and V11 at VEGP. The maximum calculated temperature for all three cases for the critical parts analyzed for all four valve types is less than the established qualification temperature. The detalled calculations for all the equipment and cases discussed herein are on flie at Westinghouse and are available for audit.

PE90E/20E/860520:12 13 i

HESTINGHOUSE PRCPRIETARY CLASS 3 i

6.0 MARGIN Significant margin has been incorporated throughout this analysis as described below. _

6.1 A margin of more'than 15aF exists in all cases between the maximum critical component temperature determined in this analysis and the previously established qualification test temperature.

6.2 The heat sink effect of the masses of material attached to the critical components analyzed herein was neglected. Since the calculated component temperature is inversely proportional to the mass of the component, inclusion of the larger masses in the analysis would reduce the component temperature.

6.3 The scaling of the Franklin test results (Reference 3) to the analysis contained herein is conservative because the Franklin steam chamber velocities and pressures are higher than the associated values in the

• VEGP Control and Auxiliary Buildings.

6.4 The geometric shapes used to calculate the maximum component temperature are the worst shapes applicable to that component in terms of forced convection heat transfer.

7.0 CONCLUSION

Based on the thermal analysis discussed herein, Westinghouse concludes that the maximum temperatures of all the equipment discussed herein exposed to MSLB's in the Control and Auxiliary Building will be less than the established qualification test temperatures for that equipment as referenced herein.

I l

l l

PE90E/20E/860520:12 14 L

WESTINGHOUSE PROPRIETARY CLASS 3

~

8.0 REFERENCES

1. Frank Kreith, Principals of Heat Transfer, Third Edition, p.14.

2. P. J. Blondo, "ASCO Solenoid Valve Qualification to a Derated Westinghouse Generic LOCA/MSLB Proflie," WCAP 8687, Supplement 2 -

H-02A/H05A, Addendum 1.

3. NUREG/CR-3424, " Test Program and Failure Analysis of Class IE Solenoid Valves."

4. Incorpera and Dewitt, Fundamentals of Heat Transfer, 1981, p. 183.

5. Frank Kreith, Principals of Heat Transfer, Third Edition, pp. 468-473.

6. Incorpera and Dewitt, Fundamentals of Heat Transfer, 1981, p. 345.

7. NAMCO Qualification Test Report, No. QTR 105, Revision 1, August 28, 1980'.

8. Isomedix Test Report No. AQS21678/TR, Revision A, July 1979.

9. Limitorque Test Report No. B-0027, Revision A, October 18, 1978.

10. Limitorque Test Report No. 600456, December 9, 1975.

11. Paul Monroe Hydraulics Generic Modulating Operator Report, PA 86468, February 13, 1981.

12. Rockw611 International Report No. 2938-01, April 1980, " Generic Qualification and Seismic Qualification Program for the Rockwell Type A Gas Hydraulic Valve Actuators."

PE90E/2CE/860520:12 15

r

t. HESTINGHOUSE PROPRIETARY CLASS 3 Table 1 THERMAL ANALYSIS RESULTS Calculated

• Qualification

• Component imax(*F) Test Tmax (*F)

1. MSIV Bypass Valve

a. NAMCO EA180 switches 310 340

b. ASCO NP8320 valve 329 346

2. Aux. FH Pump Discharge Valve

a. Limitorque S8-00 Operator 255 310

3. Atmos Steam Dump Valve (PORV)

a. Shroud 272 350

b. Keane 4-way solenoid valve 286 350

4. Main Steam Isolation Valve (MSIV)

a. Keane 3-way solenoid valve 309 355

b. NAMCO EA-180 switches 310 340

• The temperature listed in the column represents the worst case of the three cases (V01, V02, Vll) analyzed.

• • These temperatures reflect actual test temperatures obtained during qualification testing. ,

PE90E/20E/860520:12 16

Attachment 3 FSAR Changes

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TABLE 3.6.1-2 (SHEET 1 OF 2) -

f DESIGN COMPARISON TO POSITIONS OF NRC BRANCH TECHNICAL POSITIONS ASB 3-1 d

trench f

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preteetlen er essentist systsee esed components egelnet gestvleted piping reitures In high- er moderate-energy rIuld systems that operste during normet plant condl-tiens ered that are located outside er contelnment should be previded.

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' accommodote thersel, selsele, and seleele artefter

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The DBA and post-DBA qualification time durations are identified in table 3.11.B.1-2. These values are based on the length of time the equipment is required to provide its safety-related function in the accident environment and whether the equipment performs its function automatically or manually., Where post-DBA functional requirements after performing the safety-related function are different from the DBA requirements, the following are considered:

s J

r. .

9

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L 3 '

)

l, -

v . . . 1, Amend. 14 2/85 3.11.B.1-3a Amend. 20 12/85

(7NSE27 A The main steam and main feedwater isolation valve areas have been evaluated using VEGP specific blowdown data which includes superheat. The main steam piping in the MSIV compartments is designed to the break exclusion (superpipe) criteria of Branch Technical Position MEB 3-1 it,em B.I.b for the portions of piping passing through the primary containment and extending to the first five-way restraint past the MSIVs as discussed in paragraph 3.6.2.1.1.0, The generic mass and energy releases of the Westinghouse Owners Group for high energy line break /superheated blowdown outside containment were evaluated to determine the temperature profiles in the VEGP MSIV compartments. Based on these results the following cases were reanalyzed using a VEGP specific model and input.

e -Two power levels were assumed: 102% and 70%

e Four break sizes were assumed: 1.0, 0.7, 0.5, and 0.4 ft' These break sizes represent the following:

- 1.0 ft' is the largest postulated break in superpipe.

- 0.7 ft' is the largest break downstream of the MSIV where the temperature envelope (Figure 3.11.B.1-1 sheet 7) is exceeded prior to protection actuation.

- 0.5(lsthelargestbranch11nebreak.

e 5535t 1

? ., . . . . . - . .. . .. . .. . .

- 0.4 ft' is the smallest break that occurs with the resulting compartment temperature exceeding 320*F (the current specified qualification temperature). .

e Two auxiliary feedwater (AFN) conditions were assumed: three AFN pumps and two AFM pumps Cases were run with and without the turbine-driven pump available to model superpipe breaks where a single failure is not considered and branchline breaks where a single failure is considered.

The analyses of the environmental response of each MSIV compartment to MSLBs with superheated steam blowdown is consistent with the requirements of NUREG-0588. These analyses were completed using the Bechtel computer code "FLUD." FLUD is a multi-node, one-dimensional, thermal-hydraulic code which takes credit for heat transfer to the surrounding concrete structures.

A facility response evaluation was performed to determine if the equipment was essential for a MSLB in the area, and the environmental qualification test reports for the essential equipment were reviewed to ensure that the equipment was quallfted for the MSLB event. For four components (MSIVs, MSIV bypass valves, steam generator atmospher!c relief valves, and aux 111ary feedwater discharge valves), the maximum MSLB environmental temperatures achieved during the qualification tests did not envelope the maximum MSLB environmental temperature profiles considering superheat developed for the control building and auxiliary building MSIV compartments. A thermal lag 5535t 2

. . . - . . .o. ..-.....: - . . - . . . . . . . . . . . . - . . . . . . .

analysis was performed on these components to demonstrate that the actual a

safety-related component temperature achieved under the VEGP MSL8 conditions ,

is less than the component temperature reached in the qualification testing program. -

The essential equipment for an MSLB in the auxiliary .and control building MSIV compartments has successfully completed environmental qualification test programs which, in conjunction with thermal lag analysis, demonstrate that the equipment is quallfled for the maximum MSLB environmental temperature postulated in these compartments. It is concluded that no required safety components are precluded from performing their safety function in the event of an MSLB in either of the MSIV compartments.

Therefore, no safety implications exist to prevent safe shutdown of the VEGP.

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REFERENCE

1. Georgia Power Company letter from D. O. Foster to NRC, dated June _,

1986.

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Watertight doors between these rooms prevent propagation of flooding and ensure that adequate capacity of the,AFW system is maintained.

Analysis of the other hazards shows that adequate redundancy and separation are provided to ensure the operability of at

-least one train of the AIW system.

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3 F.';4. 2

• MAIN STEAM ISOLATION VALVE (MSIV) AND MAIN FsEDWATER ISOLATION VALVE (MFIV) COMPARTMENT The MSIV/MFIV compartment is located in the wing areas of the

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' auxiliary building and the control building. Figure 3F-3 provides plan and elevation views of this area. The main steam and main feedwater piping in this area consists of straight piping runs extiending from the containment penetrations to torsional restraints mounted in the auxiliary building and control building walls through which these lines enter the main steam turmel. The MSIVs, main steam safety valves, atmospheric relief valves, d MFIVs are in this compartment. Also in the compartment ar T r. r i e u p z : : : r : tr----4++1 h @ ranch piping lines of the A system 7 che M dition sy~ stem, steam supply to the turbine-driven AFW pump, bypass loops of the MSIVs, pressure instrumentation, and drains.

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3F.4.2.1 Break Size and Location Main steam and feedwater piping in this compartment is designed to the criteria stated in paragraph 3.6.2.1 for those portions l22 of the piping passing through the primary containment and extending to the first pipe whip restraint past the first outside isolation valve. In accordance with these criteria, no specific pipe breaks are postulated in the main run of these lines in the MSIV/MFIV compartment. However, to-provide an l22 additional level of assurance of operability o'f safety-related equipment in this compartment, the building structure and T safety-related equipment are designed for the environmental J conditions (pressure, temperature, and flooding) that would result from a break, equal in area to one cross-sectional pipe area (s}{,s_.m_ r-of_.either

_ 3snses.ier QkndIe. aimairts_t3am ac.averg,lina -or_mainJeedwater_

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rupture is limited by providing adequate venting of the T compartment and designing the compartment to withstand the f maximum resultant pressure. Venting is accomplished by

• { including adequate passageways between compartments or by other acceptable venting schemes. Engineered safety features '

required to bring the reactor to safe , shutdown, which are

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located within these compartments, are designed to withstand the associated temperature, pressure, and humidity. conditions.

' ( The following cases are analysed to determine the worst environmental conditions for $he MSIV/MFIV compartment:

A. Case 1: Blowdown from a main steam line break (MSLB)

'* . ~ '~ equivalent to the flow area of a single area rupture (1.84 ft'). This case resA g in the maximum t *(- compartmen pressure. -

B. Case $2: Blowdown from's main feedwatar line break equivalent to the flow area of a single area rupture (1.4 ft ).

8 This case results in the maximum compartment flood _leXely -- -

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_,,j The case 1 analysis was performed using the COPDA computer .<

code, which is described in reference 1. The case.2 analysis

! was performed using the fluid flow equations identified in

( reference 2 for cold water flow.

3F.4.2.3 Mass and Energy Release for Main Steam Line Break N

Using the method outlined in appendix E of ANSI N176, blowdown Er casei was calculated from a single area rupture of the 38-in, main s steam line at the 38 by 38 by 26-in. tee. This methodology results in flowrates that are upperbound values for any steam line break outside containment. .

The limiting plant condition in terms of both . steam generator mass inventory and initial secondary system pressure is obtained when the plant is at hot shutdown.

The blowdown obtained is listed in table 3F-3.

3F.4.2.4 Compartment Volumes and Vent Areas 7

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Tor the analysis of the pressure temperature-transient j I M ollowing a MSLB (case 1), the flow model of control volumes,

,. intercompartment flow paths, and corresponding flow coefficients are illustrated in figure 3F-4 and table 3F-3.

.! The calculated compartment pressure-temperature response is shown in figure 3F-5 and table 3F-3.

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