ML20100P898

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Main Steam Tunnel Temp Response for Linear Leakage Ramp Rate Sensitivities
ML20100P898
Person / Time
Site: LaSalle  Constellation icon.png
Issue date: 02/29/1996
From: Beaumont E
COMMONWEALTH EDISON CO.
To:
Shared Package
ML20100P861 List:
References
BSA-L-96-06, BSA-L-96-06-R00, BSA-L-96-6, BSA-L-96-6-R, NUDOCS 9603110397
Download: ML20100P898 (16)
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LaSalle Main Steam Tunnel Temperature Response for Linear Leakage Ramp Rate Sensitivities Document Number BSA-L-96-06 Revision 0 l

l Eric T. Beaumont BWR Safety Analysis Nuclear Fuel Services Department Downers Grove, Illinois O

Prepared by: /b ' Date: 2//4/9g Reviewed by: N A, - .[ _ Date: 2/2y/9g Approved by: h '

Date:

(Date issued)

II 9603110397 960301 PDR ADOCK 05000373 P PDR

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' BSA L 96-06 Rsvision 0-i Statement of Disclaimer This document was prepared by the Nuclear Fuel Services Department for use internal to the Commonwealth Edison Company. It is being made available to others upon the

! express understanding that neither Commonwealth Edison Company nor any of its officers, directors, agents, or employees makes any warranty or representation or assumes any obligation, responsibility or liability with respect to the contents of this document or its accuracy or completeness.

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BSA-L-96-06 R; vision 0-Release of Information Statement This document is furnished in confidence solely for the purpose or purposes stated. No other use, direct or indirect, of the document or the information it contains is authorized.

The recipient shall not publish or otherwise disclose this document or information therein to others without prior written consent of the Commonwealth Edison Company, and shall retum the document at the request of the Commonwealth Edison Company.

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BSA-L 96-06 R1 vision 0-Abstract The LaSalle main steam tunnel (MST) leak detection system consists of temperature '

sensors that monitor the MST temperature and ventilation system supply and exhaust air temperatures. There will be an automatic isolation signal, as the automatic isolation signal is based on differential temperatures resulting from a 100 gpm steam leak using a linear leakage ramp rate of 100 seconds. This calculation uses a GOTHIC system model to determine the MST temperature response due to a 100 gpm steam leak, VR i supply air temperatures of 110 degrees F, and a variety of linear leakage ramp rates.

The results are intended to be used to determine the sensitivity of ramp rate on upper MST temperature.

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CSA-L-96-06 R: vision 0-Table of Contents 1 . I n t ro d u cti o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2. Methodology /Model Description and Assumptions ..................................................... 2
3. M o d e l B e n c h m a rk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4.Results........................................................................................................................4

5. C on cl u sio n s/D isc u ssion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6. References.................................................................................................................7 Appen dix A - Mic rofich e I ndex . . . . . . . . . . . . . . . . . . . . . . .... . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . ... . . . . . .. . . . . . . . . . . . . . . . . .. . . . 8 Appendix B - Input Data Set Protection Form................................................................. 9 1

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CSA L-96-06 Rsvision o-List of Tables Table 1 : Steam Tunnel Temperature Variations with Linear Leakage Ramp Rate approximately 10 Minutes (8.33 minutes) after Fully Developed Leakage ............. 4 Table 2 : Steam Tunnel Temperature Variations with Linear Leakage Ramp Rate approximately 30 Minutes (28.33 minutes) after Fully Developed Leakage ............ 4 vi

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List of Figures l 1

Figure 1: Upper MST Temperatuie Response for Various Leakage Ramp Rates.......... 5 l

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BSA L 96-06 R; vision O~

1. Introduction The LaSalle main steam tunnel (MST) leak detection system consists of temperature  ;

sensors that monitor the MST temperature and ventilation system supply and exhaust air temperatures. There will be an automatic isolation signal, as the automatic isolation signal is based on differential temperatures resu!!ing from a 100 gpm steam leak using a linear leakage ramp rate of 100 seconds. This calculation uses the bounding  !

conditions from the Reference 1 analysis and a variety of linear leakage ramp rates.

The results are intended to be used to determine the sensitivity of ramp rate on upper ,

MST temperature.

l The purpose of this calculation is to determine the MST temperature response due to a variety of leakage ramp rates for the bounding conditions determined in Reference 1.

The results are intended to be used to show that the upper MST temperature is insensitive to the leakage ramp rate.

This sensitivity study is being performed to address an RAI on the LaSalle MST temperature setpoint methodology change. RAI 4 and its response can be found in Reference 2.

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2. Methodology /Model Description and Assumptions The main steam tunnel temperature response was calculated by a GOTHIC system l model. The steam tunnel configuration, the transient due to a steam leak, the analytical

! model, the computer code, the input parameters and the assumptions used in this analysis are identical to those used in Reference with the following exception.

l Assumption 11 in Reference 1, section 2.5 is the starting point for the sensitivity study.

l including this base case, five GOTHIC runs were made. The following leakage ramp rates were used: 0.001 seconds,50 seconds,100 seconds,500 seconds and 1000 seconds. This was accomplished by changing one number in a function table for each case.

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3. Model Benchmark I

The validity of the analytical modelis established by comparing the GOTHIC model results with plant measured data. Figure 3 from Reference 1 shows the benchmark data. This plot shows very good agreement between the calculated results and plant  !

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4. Results Figure 1 shows the upper MST temperature response as a result of a 100 gpm of steam leakage for all five leakage ramp rates. The leak is initiated at time equal to 1000 seconds. Within the first ten minutes the upper MST temperature shows up to 1.3 degrees difference between the different leakage ramp rates. However, within 30 minutes (steady state achieved) the upper MST varies by only 0.1 degroes for the different leakage ramp rates.

The results presented in Figure 1 are also listed in Tables 1 and 2.

Table 1 : Steam Tunnel Temperature Variations with Linear Leakage Ramp Rate approximately 10 Minutes (8.33 minutes) after Fully Developed Leakage Linear Ramp Rate Upper Steam Lower Steam Middle Steam (seconds) Tunnel Tunnel Tunnel Temperature (F) Temperature (F) Temperature (F) 0 182.7 206.3 206.9 50 182.5 204.9 205.6 100 182.5 204.8 205.6 500 181.4 203.9 204.0 1000 181.8 204.5 206.1 Table 2 : Steam Tunnel Temperature Variations with Linear Leakage Ramp Rate approximately 30 Minutes (28.33 minutes) after Fully Developed Leakage Linear Ramp Rate Upper Steam Lower Steam Middle Steam (seconds) Tunnel Tunnel Tunnel Temperature (F) Temperature (F) Temperature (F) 0 183.3 207.0 207.3 50 183.3 207.0 207.2 100 183.3 207.0 207.3 500 183.4 207.3 207.5 1000 183.4 207.5 207.7 1

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CSA L-96-06

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10 Minutes After Leak 184.5 - -30 Minutes After Leak l

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180.0 0 100 200 300 400 500 600 700 800 900 1000 Leakage Ramp Rate (seconds)

Figure 1: Upper MST Temperature Response for Various Leakage Ramp Rates 5 of 9

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5. Conclusions / Discussion Table 1 showed the results for the specified ramp rate 10 minutes after the leak has fully developed which is consistent with the values listed in Reference 1. Table 2 showed the results for the ramp rate 30 minutes after the leak has fully developed.

Although there are variations of approximately 1.3 degrees in Table 1 for the upper MST, this is not a concem since the temperatures continue to increase. Table 2 shows that once these temperatures reach a true steady state there is less than 0.1 degrees  ;

variations in the upper MST because of the ramp rate. The results show that the steam tunnel temperature response is relatively insensitive to the linear leakage ramp rate.

For consistency with values in Reference 1, values at 8.33 minutes and 28.33 minutes after fully developed leakage were used. Hence the upper MST temperature response is insensitive to variations in the leakage ramp rate. ,

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CSA-L-96-06 Revision 0-

6. References
1) BSA-L-95-05, Revision 0,"LaSalle Main Steam Tunnel Temperature Response Due to Steam Leakage with Ventilation System in Operation", January 13,1996
2) NFS:BSA:96-020, Memo to File," Verification of GOTHIC runs for LaSalle main Steam Tunnel RAI 4," February 23,1996 l

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Appendix A - Microfiche index Microfiche ID # of fiche Description NFSEBX 1234 1 0.001 Second ramp rate NFSEBX 1234 1 50.0 Second ramp rate NFSEBX 1234 1 100.0 Second ramp rate NFSEBX 1234 1 500.0 Second ramp rate 1 NFSEBX 1234 1 1000.0 Second ramp rate l

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BSA-L-96-06 Revision 0 Appendix B - Input Data Set Protection Form Station: LS Unit: both Cycle / Analysis: all checksum s'

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Current File Location 1 su m -r sum -p

1. Infs/sa/nfseb/ gothic /Is/ ramp /new/v400_v667/rampsens/Oramp 11751 2534531472
2. Infs/sa/nfseb/ gothic /Is/ ramp /new/v400_v667/rampsens/50 ramp 48807 1833529052
3. Infs/sa/nfseb/ gothic /Is/ ramp /new/v400_v667/rampsens/100 ramp 48240 3425756220
4. /nfs/sa/ntseb/ gothic /Is/ ramp /new/v400_v667/rampsens/500 ramp 30011 3268254251
5. /nfs/sa/nfseb/ gothic /Is/ ramp /new/v400_v667/rampsens1000 ramp 49176 1974590145 Notes: 1) Infs/se is not required. Begin each fRe location with user id. FRe name should be descriptive and include a means of identifying associated computer code.
2) Station, Unit, and Cycle / Analysis win define part of the destination location in Infs.databank/SA therefore, these are not need in the " Copy To* column.
3) The SA Admin wiR place a check mark next to the veiified checksum numbers ,

Author: Reviewer: ' /] _ min: Date:

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