ML20114D511
| ML20114D511 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 08/31/1992 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ULNRC-2691, NUDOCS 9209090069 | |
| Download: ML20114D511 (5) | |
Text
d s
i 1901(? %'em $ V o 4
lurD"aitsin b i l : > > >.W. ' ': !. ?.' { f
]1& Va i 4
\\
Umax
" ~ ' " " ~ "
Eucnue
^un"c
'1-1" w
i b
U.S. Nuclear Regulatory Contuission Attn Document Control Desk Mail Station P1-137 Washington, DC 20555 Gentlemen:
ULNRC-2691 CALLAWAY PLANT DOCKET NUMBER 50-483 RESPONSE 'IV REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION TO TECilNICAT, SPECIFICATION 3/4.9.12 "SEMP FUE]A.1MISMlUJ.32DEAGH" Ref 1.
ULNRC-2647, 6/12/92, Callaway Plant / Docket l;
Ntunber 50-4 83/ Revision to Technical L
Specification 3/4.9.12 /' Spent Fuel Assemb'.y Storage'"
Union Electric Company herewith responds to an NRC request for additional information regarding our previously submitted application for amendment to Facility Operating License Number NPF-30 for the Callaway Plant (Reference 1).
In-a telephone conversation with Union Electric personnel on August 4, 1992, the NRC staff requested additional information regarding codes, methodology, and modelling which account for differences between the k-infinity versus pool water temperat're curves of Reference 1 and the Callaway Final Safety Analysis Report, i.e.,
Figure 15 and Figure 9.1A-22, respectively.
Union Electric's responee to the request for additional information'is herewith attached and, as requested by the staff on August 20, 1992, is submitted for inclusion on the Callaway docket.-
If any additional information is needed, please contact us.
Very truly yours, Gk
& -n Donald F. Schnell GAC/kea 040009 Attachment 9209090069<920031 dO -
PDR ADOCK 0D000483 f I I
,P
.PDR-L
m; 3
.i j
Atttachment ULNRC-2691 K INFINITY VERSUS TEMPERATURE DISCREPANCY CALLAWAY REGLON 2 CRITICALITY ANALYSIS An evaluation was performed to resolve the discrepancies between the k-infinity versus temperature cutves for the Region 2 spent fuel rack analysis performed by Union Electric (UE) and that previously performed by Pickard,.Lowe, and Garrick (PLG).
The previous analysis showed a constant increase in k-infinity with temperature, while the UB analysis shown k-infinity peaking at approxinately 90 degrees F and then decreasing.
The major areas which were reviewed to determine the cause of the SJ discrepancies in the curves are:
1)
PDQ model geometries, 2) cross sectior, data (trends with temperature), and 3) cross section generation models.
The UE models used the CASMO and GRPDQ codes for determining overall spent fuel rack k-infinities, while PLG utilized the LEOPARD, CINDER, and PDQ codes.
Comparison of the-PDQ input decks showed that the overall models were similar with fuel in three out of four cells and the fourth cell being a water hole (flux trap).
The UE model used a c
finer mesh spacing for the gap and stainless steel to better model the changes in flux.
The actual cross section data was also compared to determine any poss.ible discrepancies.
Review of the cross section data showed some minor deviations as trended by temperature, mostly with respect to water and stainless steel.
This may be partly attributed to the use of finer mesh spacings by UP when generating the cross section data using CASMO.
The other noted disparity in cross section data is use of a different set of cross sections by UE for the water in the fuel cells versus the water in the flux trap region.
This approach was utilized due to the i
differences in spectrum with a large water gap versus the gap betweenithe fuel assembly and the stainless steel.
The-final area of comparison was the codes utilized to generate the actual macroscopic cross section data.
PLG
- used'al4 group input from LEOPARD / CINDER to PDQ (diffusion theory code), while UE used-a'four group input from CAGMO-to
~
- GRPDQ (a modified version of PDQ 7).
CASMO generates cross section data from a 40-group-nuclear data library, ENDF/B-V, while LEOPARD uses a cross section library which pre-dates ENDP.
It should be noted that_the CASMO_ code _usedlby UE for generating cross sectione is a multi-group two-dimensional
. transport theory code.
- he LEOPARD'and CINDER codes are not considered to.be as rigornus mathematically as CASMO.
Since UE does not use the LEOS, or CINDEP codes, the inputs could not be compared ts natermine any other modeling
. differences.
Also,.information on the composition of the LEOP.ARD library was not available.
As a final check, several PLG input decks for PDQ were run using the GRPDQ M1 Page 1 of 2 D
g ee e n w-+ c.-
,yN-6,--v---.,h c%,
v,9w-m-
~,c#
,.,-,y..we g,i w n w %,
m y,e w
--,gw-.nw-n,+-
v
.m-y ye ymw v,m rev-e -
re, v
vv w
s w*pw+,y->W"
m______._._....__-._._.
__....___.__,__m_
Atttachment ULNRC 2691 code.
No differences were noted f"om the PLG results, thus the PDQ codes can F>e eliminated as a source of error.
In summation, the discrepancy in the k-infinity vs.
temperature curves for the-UE and FA analyses is mainly due to differences in cross section data, some minor modeling differencen, mestly in the area of mesh spacing in the gap and stainless steel regions by UE, and improved codes and methodology.
Based on the above, it is UE's conclusion that
)
the " humped" teinperature curve is a more theoretically j
correct representation of the pool temperature effects on i
k infinity.
B t
i 4
4 Page'2 of 2
~. _,..- a n
a
.. m
~-
t STATE OF MISSOURI )
)
Donald F. Schnell, of lawful age, being first duly sworn upon oath says that he is Senior Vice President-Nuclear and an officer l'
of Union Electric Company; that he has read the foregoing document and I
k'iows 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 l
that the facts therein stated are true and correct to the best of his knowledge, information and belief.
By.
- r<,e
/
Donald F. Sc'hnell Senior Vice President Nuclear-SUBSQRIBED and sworn to before me this 3 4' I--- day of //#CuI --
- 1992, il
-?
$kA 9 /
l bff
.,1
- 7
~
BARGARA J. IfAff NOTAM PU0 tic, 51 ATE Of VISSOURI My COMMISSION LXP!MS APRll 22. 1993 ST. LOUls COUNTY i
4 e
cci T. A.
Baxter, Esq.
Shaw, Pittman, Potts & Trowbridge r
2300 N. Street, N.W.
Washington, D.C.
20037 Dr. J. O.
Cormak CFA, Inc.
18225-A Flower Hill Way f
calthersburg, MD 20879-5334 L.-Robert Gregor Chief, Reactor Project Branch 1 U.S.
Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 r
Callaway Resident Office U.S. Nuclear Regulatory Commission RR#1 Steedman, Missouri 65077 L. R. Wharton (2)
Office of Nuclear Reactor Regulation U.S.
Nuclear Regulatory Commission 1 White Flint, North, Mall Stop 13E21 11555'Rockville Pike Rockville, MD 208b2 Manager, Elcetric Department Missouri Public-Service Commission P.O.
Box 360
-Jefferson City, MO 65102 W
Ron Kucera-Department of Natural Resources P.O.-Box 176 Jefferson City, MO 65102 o
L l
[
l
.