ML20125D370
| ML20125D370 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 12/04/1992 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ULNRC-2734, NUDOCS 9212150140 | |
| Download: ML20125D370 (5) | |
Text
, _ _.
1-1901 Chouteau Avenue
' Post Ottce Bcx 149
-'"?
St. !ok FAvoun 63166 3 < 4 h54-2650 4 :.
i e'
IINION Donald F. Schtrell semor va news ELECTRIC nuww v
13 December 4, 1992 U.S. Nuclear Regulatory Commission 1
Attn:
Document Control Desk i
Mail Station P1-137 1
Washinoton, DC 20555 i
l Gentlemen:
"LNRC-2 734 CALLAWAY PLANT i
DOCKET NUMBER 50-483 ADDITIONAL INFORMATION REGARDING REVISION TO TECHNICAL SPECIFICATION TABLE 4.3-1,
" REACTOR TRIP SYSTEM INSTRUMENTATION SURVEILLANCE REQUIREMENTS" Ref:
1.
Union Electric letter to U.S.-Nuclear
[
Regulatory Commission, ULNRC-2718, November 3, 1992 Att:
1.
Calibration of Source Range Instrument.ation Using the Plateau curve and Integral Bias Curve Methods i
In Reference 1, Union Electric Company submitted the subject application for' amendment to Facility Operating License Number NPF-30 for the Callaway Plant.
This amendment application requests a revision to. Technical-Specification Table 4.3-1, Note.
5, to reflect.that integral bias curves, rather than dete:ctor plateau curves, ere used to calibrate the source r nge instrumentation.
It'is a more inclusive calibration than the plateau curve and provides the same information, i.e.,'the-high voltage operating-point.
Union Electric herewith submita additional information regarding the calib. ration of source range instrumentation using the plateau curve.and integral bias curve methods- (Attacrment 1).
110 W
&lf 2
1 212150140 921204-9 t
PDR ADOCK 05000483
.] \\.
=
[
p
.PDR
U.S.
Nuclear Regulatory Commission Page 2 If you have any questions regarding this matter, please contact us.
Very truly yours, j
+
Donald F.
Schnell GAC/plh Attachment 1
4 L
i.
j i-i
- Attachment 1 l
.ULNRC-2734 i
r
[
Calibration of Source:RangeLInstrumentation Using j.
the Plateau Curve and Inteoral Bias Curve Methods
[
At the Callaway Plant, the= implementation of--the Boron-I Dilution Mitigation System added a low-noise preamplifier.
(" preamp") to the source range-dectector1 channel of the Nuclear Instrumentation-3ystem.("NIS")._during the original. design..The i
low-noise preamplifiers.provided for the:Callaway-Plant NIS do i-not provide a means of determiningjthe detector voltage setting
~
i using the traditional high voltage plateau curves.. Beca'Ise the j'
preamp is a voltage. sensitive design, the detector plateau curve no longer retains the typical " knee" of the curve'and the plateau-length.
l The calibration ofLthe source range'NIS is currently _
E performed by using an integral bias curve rather than a plateau i
curve.
The integral bias curve sets up=the high. voltage as well as the preamp gains and. discriminator bias.
It is a more j
inclusive calibration than the plateau curve and provides the j
same information' i.e.,-the high voltage operating point.
Using the integral bias curve method, the operating bias point is determined-from a graph ~of the curveLof count-rate.
4 l
versus discriminator bias.
The operating point for the.
i discriminator is determined =by adding! margin against possible I
noise pulses to the value-where the curve departs'from the best fit straight line..The detector high voltage-is adjusted-if the discriminator operating bias. point'is not where it is required.to I
be.
l
[
l L
z.
a..~._.._.-.:_..-...-__,,;_
)
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.
I By MM
~
Donald F.
Schnell Senior Vice President Nuclear SUBSCRIBED and sworn to berore me this N day bjdnAL:j, of 1992.
1 i
- C L L ra & $ - / - !A-J' S Notary Public/'
p' e-l BAriaAR A J. PFAFF i
NOTARY PUBilC. SI ATE OF MIS 50VR1 l
MY COMMISS!ON EXPIRES APRIL 22. 1993 l
ST. LOUIS COUNTY i
1 I
i
1 i
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 i
Chief, Reactor Project Branch 1 U.S.
Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Bartlett Callaway-Resident Office j
U.S.
Nuclear Regulatory Commission RR#1 Stecdman,JMissouri 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
........