ML17334B289
| ML17334B289 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 01/12/1989 |
| From: | Alexich M INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Murley T NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| AEP:NRC:1024F, TAC-64962, NUDOCS 8901190149 | |
| Download: ML17334B289 (10) | |
Text
gZCE RATED DIG>~BUTION DEMONSTR"TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:8901190149 DOC.DATE: 89/01/12 NOTARIZED: NO DOCKET FACIL:50-315 Donald C.
Cook Nuclear Power Plant, Unit 1, Indiana 05000315 50-316 Donald C.
Cook Nuclear Power Plant, Unit 2, Indiana 05000316 AUTH.NAME AUTHOR,AFFILIATION ALEXICH,M.P.
'ndiana Michigan Power Co.
(formerly Indiana
& Michigan Ele RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Summarizes 890103 telcon w/NRC,Westinghouse
& AEPSC re questions on WCAP 11908, "Containment Integrity...."
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indiana Michigan Power Company P.O. Box 16631 Coiumbus, OH 43216 AEP:NRC:1024F TAC NO.
64962 Donald C.
Cook Nuclear Plant Units 1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
DPR-58 and DPR-74 ADDITIONAL INFORMATION ON CONTAINMENT LONG TERM PRESSURE ANALYSIS U.S. Nuclear Regulatory Commission Attn:
Document Control Desk Washington, D AC.
20555 Attn:
T.
E. Murley January 12, 1989
Dear Dr. Huxley:
This letter and its attachment summarize a phone conversation held on January 3,
- 1989, among members of your staff, Westinghouse Electric Corporation, and AEPSC.
The meeting was held to respond to NRC questions regarding WCAP 11908, entitled "Containment Integrity Analysis for Donald C.
Cook Nuclear Plant Units 1 and 2
July 1988."
The analysis was submitted for NRC review in our letter AEP:NRC:1024D, dated August 22, 1988.
At the conclusion of the meeting, the NRC staff informed us that their questions were satisfactorily answered.
At the staff's
- request, Westinghouse Electric Corporation has summarized the response to those questions, in writing.
The summary is contained in the attachment to this letter.
This document has been prepared following Corporate procedures that incorporate a reasonable set of controls to ensure its accuracy and completeness prior to signature by the undersigned.
Sincerely, M. P. Ale ich Vice President MPA/eh AnOCy S>ogq~
OS iS oq<Z F'50Op>>>
PDr oI
~
~
Dr. T.
E. Murley AEP:NRC:1024F Attachment cc:
D. H. Williams, Jr.
W.
G. Smith, Jr.
- Bridgman R.
C. Callen G. Charnoff G.
Bruchmann A. B. Davis - Region III NRC Resident Inspector
- Bridgman
ATTACHMENT TO AEP:NRC'1024F ADDITIONALINFORMATION ON CONTAINMENT LONG TERM PRESSURE ANALYSIS
FROM:ECE TO:86142232884 JAN 11 1989 12:38'.82 Westinghouse Electric Corporation Energy Systems Nuclear and Advanced yechnorogy Oivision Boy 355 Pittsburgh Pennsylvania 15230 0355 January 11, 1989 AEP-89-101 NATO/SI-794/89
,I ar Mt'. R. B. Bennett 1 Riverside Plaza P.O.
Box 16631
- Columbus, Ohio 43216-6631 American Electric Power Service Corporation O.C.
Cook Units 1 5 2 Rerating Program Res onses to NRC Reviewers'estions on WCAP-11908
Dear Mr. Bennett:
As agreed to in the telephone conference of January 3, please find attached the formal responses to the NRC reviewers'uestions on WCAP-11908, regarding the long term containment integr1ty analys1s for the Donald C.
Cook Un1ts.
The responses incorporate the comments you telecopied to us on January 9.
Please contact me or Oeborah August1ne if you have any further questions or comments on these responses or if you requ1re any further assistance 1n this area.
HCW:OBA/sm aa:
O. II. Mttlin/I. A. Irwia V, Vanderburg R.
P. Leonard D. B. Black Attachment H. C. Halls Mid-Amer1ca Area U.S. Nuclear Projects Pi Ai %.trur.pf B. A. Svennson (D.C.
Cook Site)
K. R. Baker (O.C.
Cook Site)
O. Karnes (O.C.
Cook S1te)
JAN 11 '89 i2:33 L4EC NNC P.3 U
NRC QUESTIONS AND MESTINGHOUSE RESPONSES RELATING TO THE AEP RTP LICENSING SUBMITTAL
('MCAP-11908)
Q]o The report indicates that current operating conditions are bounding-not reduced temperatu're and pressure.
Mhat impact does RTP have on the containment analysis'P Mhat inputs are affected, and whyo'1:
For this analysis, the upper bound primary temperature and pressure conditions associated w1th the D.
C.
Cook Rerating Program (i.e.,
slightly higher operating temperature than currently licensed) represent the most conservative set of initial conditions for the long term mass and energy release transient, not reduced temperature and
- pressure, For this reason, the rerat1ng parameters were used in the analysis by virtue of maximizing the available mass and energy release to containment.
The inputs primarily affected are the initial pressure and enthalpy. arrays input to the SATAN blowdown code.
Q2:
What physically happens when you close the RHR cross-ties, and how does it impact the analysis7 A2:
The double-ended pump suction break w1th minimum safeguards has been established previously and confirmed via this analysis to be the lim1t1ng break with respect to the containment integrity peak pressure calculation.
The effect of"closing of the RHR crossties is that there is a net reduction in total pumped safety injection flow, and in addition, the number of loops receiving injection changes from 4 to 2.
This represents a reduction in safety injection flow from the minimum safeguards
- case, The result is that there is less steam condensat1on in the RCS,.with more steam be1ng released to the containment atmosphere, Thus, operation with the RHR crossties closed represents a more conservative mode of operation with respect to the containment integrity calculation.
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P.4 Q3:
If the steam/water mixing data from reference 4 are discussed in reference 1, why is it an exception to the model'2 In a response to a request for additional information from the HRC to Westinghouse regarding the review of NCAP-10325, Westinghouse stated that, although the model as described in MCAP.10325 does not explicity exclude broken loop steam/water mixirig, the implementation of the model documented in a memo from E. P.
Rahe of Mestinghouse (memo NS-EPR-2948, dated October 4, 1984),
does exclude this.
The same memo states that steam water mixing.is assumed to occur in the intact loops.
The exception to the implementation of the mass and energy release model described in MCAP-10325 is that for the D. C.
Cook analysis documented in MCAP-11908, Westinghouse has included the effects of steam-water mixing in the broken loop in WREFLOOD.
While assuming broken loop mixing is less conservative than the previous analyses, Westinghouse believes that this exception to the application of the model is technically correct and is supported by test data, by virtue of the break being located in the pump suction leg of the RCS.
This discussion follows:
In order to be able to take cradit for inclusion of the additional steam/water mixing effects in the broken cold leg, the 1/3 scale W/EPRI steam/water mixing data was examined (WCAP-8423).
The experiments showed that for'he range of conditions tested, the incoming super heated steam was desuperheated to the saturation temperature and some of the steam was condensed within three cold leg diameters of the experiment (see Appendix D 'of WCAP"8423).
The ratio of steam energy flow to in)ected flow energy sink capability for the plant was calculated for different transient times.
Similar'arameters were determined from the experimenta1 results.
Use of the energy ratio eliminates the need to inc'orporate a scaling factor when comparing the experimental results to the p1ant responses.
The values of the energy ratio for the plant are bounded by the experimental
- values, The peak ratio calculated for the plant analysis was 0.256.
The ratios determined from the experimental data ranged from 0.013 to 0.957 and therefore bound the plant condition.
8882I;1 d/011188
3'AN 11" '89 12:35
&HAEC NHC P.S i
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The mixing experiments demonstrated equilibr ium conditions within three pipe diameters of the mixing zone.
This corresponds to a length of 30 inches.
The experiments were devised and conducted such that the length af.the mixing zone for the experiments and that for the plant would be equivalent and not subject to a scaling factor.
The available distance in the plant for mixing the broken cold leg, from the inject1on point through the pump to the weld at the pump suction, is appraximately 110 1nches.
Since thermodynamic equilibrium was achieved during the experiments within 30 inches for more limiting canditions than the plant is subject to, the calculation of equilibrium effluent fram the plant's broken loop pump suctian is justified, Another point is that in the experiment, the mixing is occurring in a horizontal pipe whereas in the PMR, the mixing would occur within the cold leg pipe, but also with1n the pump diffuse sect1on where the axial flow areas are even more limiting.
The reduced flow areas will force 1mproved mixing of the two streams in the plant relative to the experiment, Therefore, again the use of an equilibrium calculation for the two-phase effluent is just1fied for this application.
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