ML20205M920
| ML20205M920 | |
| Person / Time | |
|---|---|
| Issue date: | 04/12/1999 |
| From: | Wen P NRC (Affiliation Not Assigned) |
| To: | Sepp H WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| TAC-M93299, NUDOCS 9904160094 | |
| Download: ML20205M920 (4) | |
Text
April 12, 1999 Mr. Henry A. Sepp, M:nig:r Regulatory and Licensing Engineering Westinghouse Electric Corporation l
Mail Stop ECE 4-07A Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR WESTINGHOUSE TOPICAL REPORT WCAP-14404-P, " METHODOLOGY FOR INCORPORATING HOT LEG NOZZLE GAPS INTO BASH" (TAC No. M93299)
Reference:
Memo from Peter C. Wen (NRC) to Francis Akstulewicz (NRC), " Summary of February 22,1999, Meeting with Westinghouse Regarding Hot Leg Nozzle Gap t
Application in Bash," dated March 5,1999.
Dear Mr. Sepp:
By letter dated July 26,1995, Westinghouse submitted topical report WCAP-14404-P for NRC review. On February 22,1999, the NRC staff met with Westinghouse representatives to discuss issues related to the topical. The discussions and supplementalinformation provided by Westinghouse were documented in the referenced meeting summary. The staff has completed the review of WCAP-14404 and the related information and has determined a need for additionalinformation. The staff discussed the needed information with Westinghouse representatives, John Galembush, Dan Garner and Jim Gresham in a telephone call on April 12,1999. The information requested is identified in an enclosure to this letter.' During the phone call, the Westinghouse representatives indicated that they would provide a response to this request about June 30,1999. Please address your response to the NRC Document Control Desk.
If you wish to meet with the staff to accelerate the information transfer, the staff would welcome such a meeting at a mutually convenient time. If you have any questions on this matter, I may be contacted by phone,301/415-2832, or by e-mail, pxw@nrc. gov.
Sincerely, l
Original Signed By:
1 Peter C. Wen, Project Manager 9904160094 990412 Generic Issues, Environmental, Financial PDR TOPRP EMVWEST and Rulemaking Branch
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Enclosure:
Questions on topical report WCAP-14404-P cc w/ enc: See next page
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April 12, 1999 4
Mr. Henry A. Sepp, Manager Regulatory and Licensing Engineering Westinghouse E!actric Corporation Mail Stop ECE 4-07A Post Office Box 355 Pittsburgh, Pennsylvania 15230-0355 z
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR WESTINGHOUSE TOPICAL REPORT WCAP-14404-P, " METHODOLOGY FOR
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INCORPORATING HOT LEG NOZZLE GAPS INTO BASH" (TAC No. M93299)
Reference:
Memo from Peter C. Wen (NRC) to Francis Akstulewicz (NRC), " Summary of February 22,1999 Meeting with Westinghouse Regarding Hot Leg Nozzle Gap Application in Bash," dated March 5,1999.
Dear Mr. Sepp:
By letter dated July 26,1995, Westinghouse submitted topical report WCAP-14404-P for NRC review. On February 22,1999, the NRC staff met with Westinghouse representatives to discuss issues related to the topical. The discussions and supplementalinformation provided by Westinghouse were documented in the referenced meeting summary. The staff has completed the review of WCAP-14404 and the related information and has determined a need for additionalinformation. The staff discussed the needed information with Westinghouse representatives, John Galembush, Dan Garner and Jim Gresham in a telephone call on April 12,1999. The information requested is identified in an enclosure to this letter. During the phone call, the Westinghouse representatives indicated that they would provide a response to this request about June 30,1999. Please address your response to the NRC Document Control Desk.
If you wish to meet with the staff to accelerate the information transfer, the staff would welcome such a meeting at a mutually convenient time. If you have any questions on this matter, I may be contacted by phone, 301/415-2832, or by e-mail, pxw@nrc. gov.
Sincerely, P4 c W Peter C. Wen, Project Manager Generic Issues, Environmental, Financial and Rulemaking Branch Office of Nuclear Reactor Regulation
Enclosure:
Cuestions on topical report WCAP-14404-P cc w/ene: See next page
Rcquast for Additional Information for the Westinghouse Topical Report, WCAP-14404-P,
" Methodology for Incorporating Hot Leg Nozzie Gaps into BASH" The staff has completed the initial review of WCAP-14404 and the related information submitted to support the topical review. The staff finds that the analyses and postulated behavior are based on a pre-LOCA gap size that Westinghouse substantiates by referencing original "as-built" dimensions. However, there is little information to substantiate the assumptions regarding existing gap size or that gaps are not plugged or their characteristics are not significantly perturbed by crud induced into the reactor i oolant by the blowdown, refill, or early stages of reflood. This is not sufficient to meet 10 CFF. 60.46 evaluation model requirements.
Consequently, the staff is requesting Westinghouse to provide the following information:
(1)
Please provide further information to substantiate the pre-LOCA gap size and characteristics, and (2)
Please provide further information regarding potential crud in the reactor coolant following occurrence of a LOCA and the potential effect of this crud on nozzle gap flow characteristics.
(3)
When applicable, provide uncertainty and sensitivity assessments / estimates with respect to the above information.
Examples of the requested information include, but are not limited to, the following:
(A)
Bypass flow rate determinations based upon operational data, experimental data, correlation of tha data to flow through the gaps and through other bypass paths, and correlation to actual gap size, (B)
Nozzle gap surface observations and any instances of damage, (C)
Historical data addressing nozzle interference during internals rerloval/ installation and an estimate of the anticipated gap during such operations.
(D)
Evaluation of the behavior of water (and water droplets)in the vicinity of the gap, including addressing whether a " sheet" of water can be established that results in water flow through the gap as opposed to steam flow through the gap. This should include addressing the three dimensional two phase behavior in the upper plenum as contrasted to the one dimensional analysis results discussed with the staff.
(E)
An assessment of " rattle" or its absence with respect to the presence of small clearances during normal operation.
(F)
Operationalinformation pertinent to crud and boron in the reactor coolant system; clogging of small diameter orifices, tubing connections, or gaps; and behavior during past transients or shutdown operations where observations of crud (or its absence) and its effect may provide insights.
(G)
The sensitivity of the actual fraction of gap that rnust remain to achieve claimed benefits.
(H)
An estimate of the total crud available for entrainment in the reactor coolant during the operational time of interest to this issue and its potential characteristics. (Are the aerosols mentioned in Section 1.2.4 of WCAP-14986-P of any concern to nozzle gap behavior?)
ENCLOSURE
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_e cc:
Mr. Nicholas Liparulo, Manager Equipment Design and Regulatory Engineering Westinghouse Electric Corporation Mail Stop ECE 4-15 P,0, Box 355 Pittsburgh, PA 15230-0355 Mr. Jack Bastin, Director Regulatory Affairs Westinghouse Electric Corporation 11921 Rockville Pike Suite 107 Rockville, MD 20852