ML20141N655
| ML20141N655 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/13/1986 |
| From: | Youngblood B Office of Nuclear Reactor Regulation |
| To: | Schnell D UNION ELECTRIC CO. |
| References | |
| NUDOCS 8603170454 | |
| Download: ML20141N655 (4) | |
Text
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4 Docket No.: 50-482 AFAR 131986 Mr.3.F. StAneI(
~.,
Vice President - Nuclear Kansas Gas & Electric Company 200 North Market Street Post Office Box 208
. Wichita, Kansas 67201
$thmen
Dear Mr. 4tsestee:
Subject:
Review of Steam Generator Tube Rupture Analysis The NRC staff is continuing its' review of your steam generator tube rupture analysis submitted by SNUPPS by-letter dated January 8,1986 and February 11,
.1986. The infomation requested in the. enclosure is necessary to permit the
' staff to complete its reveiw.
Please provide the requested information within 15 days of your receipt of
. this letter.
If all of the requested information request cannot be provided within the requested time provide a s<:hedule for the timely submittal of all remaining items.
Sincerely, W\\
B. J. Youngblood, Director PWR Project Directorate #4 Division of PWR Licensing-A
Enclosure:
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Mr. D. F. Schnell Callaway Plant 1-Union Electric-Company Unit No. I cc:
Mr. Nicholas A. Petrick Lewis C. Green, Esq. -
Executive Director - SNUPPS Green Hennings & Henry 5 Choke Cherry Road Attorney for Joint.Intervenors Rockville, Maryland 20850 314 N. Broadway, Suite 1830 St. Louis, Missouri 65251 Gerald Charnoff, Esq.
Thomas A. Baxter Esq.
Ms. Marjorie Reilly Shaw, Pittman, Potts & Trowbridge Energy Chairman of the League of 1800 M Street, N. W.
Women Voters of Univ. City, M0 Wn hinoten, D. C.
20036 7065 Pershing Avenue University City, Missouri 63130 Mr. J. E. Birk Assistant to the General Counsel Mr. Donald Bollinger, Member Union Electric Company Missourians for Safe Energy
-Post Office Box 149 6267 Delmar Boulevard St. Louis, Missouri 63166 University City, Missouri _ 63130 U. S. Nuclear Regulatory Comission Mr. Dan I. Bolef, President Resident Inspectors Office Kay Drey, Representative RR#1 Board of Directors Coalition Steedman, Missouri 65077 for the Environment St. Louis Region Mr. Donald W. Capone, Manager 6267 Delmar Boulevard Nuclear Engineering University City, Missouri 63130 Union Electric Company Post Office Box 149 St. Louis, Missouri 63166 Chris R. Rogers, P.E.
Manager - Electric Department 301 W. High Post Office Box 360 Jefferson City,' Missouri 65102 Regional Administrator U. S. NRC, Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Mr. Ronald A. Kucera, Deputy Director Department of Natural Resources P. O. Box 176 Jefferson City, Missouri 65102 Mr. Glenn L. Koester Vice President - Nuclear Kansas Gas and Electric Company 201 North Market Street Post Office Box 208 Wichita, Kansas 67201 Q
g" E'NCLOSURE 1 REQUEST FOR ADDITIONAL INFORMATION STEAM GENERATOR TUBE RUPTURE (SGTR) ANALYSIS CALLAWAY & WOLF CREEK PLANTS l
L 1.
The.SNUPPS analysis for the SGTR. maximum overfill case states that at the time of break ' low termination, the steam volume below the outlet nozzle is very 11 Thus, the margin to overfill for this case is minimal, and a slight change in assumptions or calculational results could result in overfill. As an example, the SNUPPS analysis apparently
. assumes reactor trip at 100% power. This assumption may not be the most conservative from a standpoint of margin to overfill and is also probably not realistic when compared to the Ginna SGTR event. A more
~
realistic scenario may involve turbine runback to some lower power followed by overtemperature delta T trip. At lower _ power levels the steam generator should have a larger liquid inventory because of reduced void' fraction, assuming the SG level remains constant. Thus, starting maximum auxiliary feedwater flow at a lower power level may result in more rapid overfill. Discuss whether this scenario (i.e., lower void fraction) was considered in your analysis and what effect it would have on the margin to overfill.
2.
Explain the basis for the large difference for reactor trip time between the " failed open AFW control valve" case and the " stuck open ARV" case and the effect of these assumptions on the analysis results.
3.
The " stuck open ARV" case assumes that the atmospheric relief valve
.(ARV) is isolated in 20 minutes by manually closing the ARV block valve. State how this time period was established and whether it is realistic considering that this operation would be performed in a location subject to adverse conditions including high temperature, radiation and noise.
w
S.'
4.
Appendix E " Bases for ARY Technical Specification" states: "An ARV is considered operable if the block valve is closed solely-becaule of
. leakage". The SGTR analysis assumes that the operator initiates RCS cooldown in'less than 30 minutes by opening the intact SG ARVs. Since the operator may have to open ~ the' ARY block valves manually if the above Technical Specification is' implemented, demonstrate that this can be accomplished within the stated time frame considering the concerns regarding this operation expressed in Question 3.
5.
In your analysis, you assumed that the fission products released to the
-intact steam generators were not released to the environment. Provide an analysis demonstrating that the fission products released to the intact steam ge'nerators will be retained in the stean, generators during the cool
.down phase.
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