ML20235S968
| ML20235S968 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 10/06/1987 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20235S971 | List: |
| References | |
| ULNRC-1643, NUDOCS 8710090206 | |
| Download: ML20235S968 (5) | |
Text
_
l
~ UNION Etscraic a
1901 Gratiot Street, St. Louis
' Donald F. Schnell Vce President October 6, 1987 U.S._ Nuclear Regulatory Commission ATTN:
Document. Control Desk Washington, D.C.
20555-Gentlemen:
ULNRC-1643 DOCKET NUMBER 50-483 CALLAWAY PLANT REVISED VANTAGE 5 TRANSITION CORE EFFECTS FOR CYCLE 3
References:
1)
ULNRC 1470 dated March 31, 1987 2)
Westinghouse Letter NS-NRC-87-3268 dated October 2, 1987 from W. J. Johnson to M. W.
Hodges I
Reference 1 transmitted the Reload License Amendment Application for Callaway Plant using Westinghouse 17 x 11 VANTAGE 5 fuel assemblies._ As part of the application, Union Electric referenced WCAP-10444-P-A, " Westinghouse Refererce Core i
l Report, VANTAGE 5 Fuel Assembly" as the approved methodology for assessing the transition to VANTAGE 5 fuel'.
Westinghouse has recently completed an assessment which affects the magnitude of the VANTAGE 5 DNB transition core penalty.
The results of this generic assessment were provided to l
NRC via Reference 2.
An evaluation has been performed for l
Callaway Cycle 3 which demonstrates-the safety evaluation 1
conclusions presented in Reference 1 remain valid, but indicates l
the need for a small (1.5 percent) correction to the magnitude of the DNB transition core penalty.
The small increase in the magnitude of the DNB transition core penalty continues to be offset by the margin which is maintained between the design and safety limit DNBRs made available due to the improved DNB performance of the IFM grids described in WCAP-10444.. The VANTAGE 5 DNB transition core penalty increases from 11 percent
~
to 12.5 percent and the DNB margin decreases from 5.5 percent to 4 percent.
.The revised transition core penalty and revised DNB margin are provided in the enclosed replacement pages to Reference 1.
8710090206 871006
\\
PDR ADOCK 05000483 P
)
y I'i\\
l^?'" ? ? ~ ~ "
~
a,
l l
l The results of the Significant Hazards Evaluation transmitted by Reference 1 remain unchanged.
If there are any I
questions with respect to this subject, please contact us.
Very truly yours, 1
Donald F.
Schnell DS/kea Attachments:
ULNRC-1470, dated March 31, 1987, Replacement Pages
- 1),
Safety Evaluation, Page 17
- 2), Technical Specification Changes, l
l Bases page B3/4.2-4
- 3), References, page 40 l
STATE OF MISSOURI )
)
Donald F.
Schnell, of lawful age, being first duly sworn upon oath says that he is Vice President-Nuclear and an officer of Union Electric Company; that he has read the foregoing document and knows the content thereof; that he has executed the same for and on behalf of said company with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.
i By Donald F. Sbhnell l
Vice President i
Nuclear j
b M day of M, 198 7, SUBSCRIBED and sworn to before me this t
BARDARA f PFAF[ [ F NOTARY PUBilC, STATE Of MISSOURI MY CO:s:SSION EXPlRES APRit. 22, 1989 ST. LOUIS COUNTY.
i i
l l
l l
l 1
l l
1 l
l l
l' l
1 cc:
Gerald Charnoff, Esq.
Shaw, Pittman, Potts & Trowbridge 2300 N.' Street, N.W.
Washington, D.C.
20037-Dr. J. O. Cermak CFA, Inc.
4' Professional Drive (Suite 110)
Gaithersburg, MD 20879 W. L. Forney.
Chief, Reactor Project Branch 1 U.S.
Nuclear Regulatory Commission Region III i
799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Little i
Callaway Resident Office U.S. Nuclear Regulatory Commission RR#1 Steedman, Missouri 65077 Tom Alexion (2)
Office of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission Mail Stop 316 l
7920 Norfolk Avenue Bethesda, MD 20014 1
\\
Ron Kucera, Deputy Director Department of Natural Resources i
P.O. Box 176 Jefferson City, MO 65102 I
Manager, Electric Department
-l Missouri Public Service Commission l
P.O. Box 360 l
Jefferson City, MO 65102 I
l 1
l I
L i
1
_..m_
.4
.._. o._ o t 'TJLWRC416 4 3 '
--~ "
ATTACHMENT 1 follows. A fraction of the margin is utilized to accommodate the transition core DNBR penalty (2% for DFA fuel and 12.5% for VANTAGE 5 fuel) and the appropriate fuel rod bow DNBR penalty, Reference 11, which is less than 1.5%.
The existing 7% margin in the DFA fuel and 38% margin in the VANTAGE 5 fuel between the design and safety analysis DNBR limits also includes a greater than 3% DNBR margin in the DFA fuel and 4% DNBR margin in the VANTAGE 5 fuel reserved for flexibility in the design. The VANTAGE 5 transition core penalty is discussed in References 27 and 28.
The LOPAR, and 0FA, and VANTAGE 5 designs have been shown to be hydraulically compatible in Reference 1.
The phenomenon of fuel rod bowing, as described in Reference 11, must be accounted for in the DNBR safety analysis of Condition I and Condition II events for each plant application. Applicable generic credits for margin resulting from retained conservatism in the evaluation of DNBR and/or margin obtained from measured plant operating parameters (such as Fh or core flow) which are more restrictive than those required by the plant safety
~
i analysis, can be used to offset the effect of rod bow. The safety analysis for the Cs11away Plant maintains sufficient margin between the safety analysis l
limit DNBRs and the design limit DNBRs to accommodate full-flow and low-flow DNBR penalties.
l The transition core DNB methodology given in References 2 and 17 has been approved by the NRC via Reference 18. Using this methodology, transition I
cores are analyzed as if they were full cores of one assembly type (full 0FA l
or full VANTAGE 5), applying the applicable trar.sition core penalties of two percent for OFA fuel and eleven percent for VANTAGE 5 fuel. The safety analyses for the Callaway Plant maintains sufficient margin between the safety analysis limit DNBRs and the design limit DNBRs to accommodate the transition core DNBR penalty and the appropriate rod bow DNBR penalty.
The fuel temperatures for use in safety analysis calculations for the VANTAGE 5 fuel are the same es those used for the OFA fuel. Westinghouse uses the PAD fuel performance code, Reference 6, to perform both design and licensing calculations. When the code is used to calculate fuel temperatures to be used as initial conditions in safety analyses, a conservative thermal safety model, Reference 7, is used.
l