ML20035E733
| ML20035E733 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 04/13/1993 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20035E734 | List: |
| References | |
| ULNRC-2790, NUDOCS 9304190165 | |
| Download: ML20035E733 (4) | |
Text
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4 1991 Ocureau Awnue Post Once Bar 149 51 imas. Mss;uri C31%
' 314 554 2C50 Donald F.Schnell
-UNION smar ace pwscent ELECTRIC N2d"8'
$ pril 13, 1993 A
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 Washington, D.C.
20555 ULNRC-2790 Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT CHANGE TO MODERATOR TEMPERATURE COEFFICIENT BASES
References:
1.
ULNRC-2528 dated December 6, 1991, Temporary Waiver of Compliance from Technical Specification 3.1.1.3 Moderator Temperature Coefficient 2.
ULNRC-2532 dated December 12, 1991, Revisions to Cycle 5 COLR EOL and 300 ppm Surveillance MTC Limits l
Union Electric Company herewith transmits changes to the Bases for Callaway Technical Specification 3/4.1.1.3, Moderator Temperature Coefficient.
The l
references cited above provide discussions related to this issue as it affected operations during Cycle 5.
The purpose of the attached changes is to revis.e the manner in which the accident analysis Moderator Density Coefficient (MDC) is converted into the End.of Cycle Life (EOL) Moderator Temperature Coefficient (MTC)
Limiting Condition ~for Operation (hereaf ter. EOL MTC LCO) and, subsequently, into a 300 ppm surveillance limit'.
The accident analysis MDC is based on EOL, hot full-power, 0 ppm boron conditions with all' control and shutdown banks fully ~ inserted (ARI).
The accident analysis-MDC, corresponding to the most negative.MTC, is used to calculate its corresponding analytical MTC limit based on the rate of change of moderator density with.
temperature at rated thermal power conditions.
This analytical MTC limit ifor an.ARI condition is then modified to reflect an all rods _out (ARO) condition-in order to arrive at a Technical Specification limi.t that can be directly compared against measured values.
This EOL MTC LCO, listed in the Core Operating Limits Report k
19QQ'[G (COLR), considers the. difference in MTC associated with-s'I
~
an ARI, core condition vs. an ARO core condition.
This g
MTC difference is much greater than that between a' core l
}
I 9304190165-930413-PDR ADOCK 05000483
- P PDR y.
u U.S. Nuclear Regulatory Commission Page 2 condition of rods inserted. to their insertion limits and all rods withdrawn.
In other words, the current Bases approach results in an unduly restrictive, more positive (less negative) EOL MTC LCO since it does not account for the Technical Specification rod insertion limits.
The g
new approach considers each plant parameter that can affect MTC (i.e. soluble boron concentration, moderator temperature and pressure, rod insertion, axial power shape, and xenon concentration) separately and assesses the sensitivity of changes in that parameter, within its applicable Technical Specification limits, on EOL MTC.
The sum of these impact assessments is then used to establish the difference between the analytical MTC limit and the EOL MTC LCO.
After adding a further allowance to this EOL MTC LCO to account for less burnup and higher soluble boron concentration, a 300 ppm equilibrium boron concentration surveillance limit is determined and also specified in the COLR.
No changes to the Technical Specifications themselves are involved since the LCO and 300 ppm surveillance limits are specified in the COLR.
A future COLR revision will document the changes to these values.
If you have any questions on the attached changes, please contact us.
Very truly yours, 1
]
l Donald F.
Schnell 1
GGY/ dis Attachments
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 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.
b
^
By n
\\/
h Donald F. S'chnell Senior Vice President Nuclear SUBSCJIBED and sworn to before me this-
/
day of Clf2U/-
1993.
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k4 /-iA AY BARBA A PF F NOTARY PU0 llc. STATE OF MfSSOURI MV COMMISSION EXPlRES APRIL 22, 1993 ST. LOUIS COUNTY j
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cc:
T. A.
Baxter,.Esq.
Shaw, Pittman, Potts & Trowbridge 2300 N.
- Street, N.W.
Washington, D.C.
20037 Dr. J.
O.
Cermak CFA, Inc.
18225-A Flower Hill Way Gaithersburg, MD 20879-5334 L. Robert Greger Chief, Reactor Project Branch 1 U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Bartlett 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, Mail Stop 13E21 11555 Rockville Pike Rockville, MD 20852 Manager, Electric Department Missouri Public Service Commission P.O. Box 360 Jefferson City, MO 65102 Ron Kucera Department of Natural Resources P.O.
Box 176 Jefferson City, MO 65102 i
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