ML19208C450

Discusses Addl Info Re two-loop Test Appartus Per NRC 790524 Request.Forwards Summary of 790824 Meeting Slides, Results from Mass & Energy Balance,Scaling,Discussion & Vaporization Data Base.W/O Encl

ML19208C450
Person / Time
Site:	Black Fox
Issue date:	07/31/1979
From:	Bochholz R GENERAL ELECTRIC CO.
To:	Shroeder F Office of Nuclear Reactor Regulation
Shared Package
ML19208C443	List: ML19208C442 ML19208C444 ML19208C449 ML19208C450
References
NUDOCS 7909260454
Download: ML19208C450 (3)

Text

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EXHIBIT II , . .

NUCLEAR ENERGY GENERALh ELECTRIC PROJECTS DIVISION GENERAL ELECTRIC COMPANY.175 CURTNER AVE., SAN JOSE. CALIFORNIA 95125 ,

MC682,(408)925-5722 MFN-198-79 July 31,1979 PTPfPfin f;rpp J

m AUG c 1979

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U. S. Nuclear Regulatory Commission Division of Systems Safety y jggcg Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Frank Schroeder, Acting Director Division of Systems Safety Gentlemen:

SUBJECT:

ADDITIONAL TLTA INFORMATION

Reference:

1) G. G. Sherwood letter to Frank Schroeder, dated

, ( 6/15/79, "Two Loop Test Apparatus (TLTA) Results"

2) R. H. Buchholz letter to Frank Schroeder, dated 7/13/79, "Leibnitz Rule in LOCA Models" Attached herein is the additional TLTA information requested by NRC during the May 24, 1379 meeting and committed by General Electric in Reference 1. Also included are additional model comparisons as requested by the NRC staff. The requested information is provided in eight attach-me its.which are summarized below for your convenience.

1. A Writeup to Support the May 24 Slides Attachment 1 is a summary of the May 24 meeting slides which presented the results of the recent TLTA tests. The relevant phenomena controlling the TLTA thermal hydraulic and bundle heatup response are identified and discussed. Comparisons of test results with and without Emergency Core Cooling (ECC) injection and a summary of the peak and low bur.dle power tests are also provided.

2. Steam Seoarator AP and Break Flow Discussion Attachment 2 presents the results from the mass and energy balance obtained from the TLTA data for the tests with and with.out ECC injection. These results clearly show that for the test with ECC injection, more liquid was entrained out the break and the buik discharged fluid quality was clearly lower. It is further concluded

( that fluid conditions discharged from the break led to the differences in depressurization rate observed between the two tests. Attachment 3 provides analysis of the steam separator pressure drop data. The ip08 9 79092e0954

GENER AL h ELECTRIC

(. U. S. Nuclear Regulatory Commission July 31,1979 Page 2

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preliminary evaluation of the separator AP suggested that the steam

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flow through the separator was lower for the test with ECC injected.

Results from Attachment 2 are utilized in Attachment 3 to further substantiate that the flow through the separator was indeed lower.

Additional analysis to include the possible effects of liquid entrainment out the separator are also included to demonstrate that the conclusions remain unchanged.

3. TLTA Scaling Discussion Attachment 4 summarizes the TLTA scaling basis and supporting aralysis. It is demonstrated that the relevant BWR LOCA thermal hydraulic phenomena can be evaluated in the TLTA.

4. Vaporization Data Base Attachment 5 provides further explanation of the facility and method used for the 1974 test which provided the data base for the vaporization correlation. Based on the recent results and data interpretation from the TLTA, it is concluded that the facility and system conditions in TLTA are similar to those of the 1974 vapori-

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zation tests.

5. Side Entry Orifice CCFL Attachment 6 describes the conservatism resultir.g from not including Side Entry Orifice (SEO) Counter Current Flow limiting (CCFL) in the General Electric evaluation model. It states that inclusion of SEO CCFL would result in core uncovery delay and earlier reflooding which would result in improved heat transfer and lower PCT's.

6. The Grid Spacer Water Accumulation Attachment 7 provides a discussion of the CCFL characteristics across a bundle. It is concluded that, while there is a potential for water accumulation to exist momentarily when there is a sudden reduction in the bundle inlet flow (e.g., during the flow coastdown period or lower plenum flashing period), accumulation will not occur during the reflood period.

7. Justification of Conservatism of the Heat Transfer Coefficients used in SAFE The information provided in Attachment 6 demonstrates that the heat transfer coefficients used in the SAFE Computer Program between the nucleate boiling to the core spray cooling regimes are the appropriate

( values.

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GEN ER AL $ ELECTRIC U. S. Nuclear Regulatory Commission

(. July 31, 1979 Page 3

8. Discussion of Plant Choice For Leibnitz Rule Study -

Response to this item was forvarded under separate cover by Reference 2.

9. Additional Evaluation of Model Comparisons Attachment 8 provides additional evaluation model comparisons of the TLTA tests with and without ECC injection. The comparisons show that the system is calculated to blowdown faster than measured due primarily to an overestimation of the break flow during the early period of the transient.

The information provided here closes out all the TLTA commitments made in Reference 1 and during discussions with the NRC staff. If further clarification is required, please contact R. N. Woldstad at (408) 925-2539 or L. F. Rodriguez at (408) 925-2460.

Very truly yours, h,% . k:-

R. H. Bu hholz, Manager

(. BWR Systems Licensing Safety and Licensing Operation RHB:gmm/421-423 Attachments cc: L. S. Gifford (Bethesda)

L. Phillips (NRC) bec: E. A. Firestone estumspe 1008 356

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