ML20217P729
| ML20217P729 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/03/1998 |
| From: | Passwater A UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ULNRC-3576, NUDOCS 9803110046 | |
| Download: ML20217P729 (8) | |
Text
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o Utn ElIctric One Ameren Plaza 1901 Chouteau Avenue PO Ilox 66149 St. lx>uis, MO 63166-6149 1
314 621.3222 March 3,1998 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stution PI-137 Washington, DC 20555-0001
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Gentlemen:
ULNRC-3576 DOCKET NUh1BER 50-483 CALLAWAY PLANT
[l UNION ELECTRIC COMPANY 7//ggg REVISION TO TECIINICAL SPECIFICATION 3/4.4 - REACTOR COOLANT SYSTEM
- E Refereece: utNRC-03664 dated Octoser 17,1997 The referenced letter requested a revision to Technical Specification 3/4.4 for the heatup, cooldown and Cold Overpressure Mitigation System (COMS) curves.
Based on discussion with the Callaway NRC Project Manger on February 27,1998, we are providing additional information in support of this amendment request.
The Attachment contains a listing of the input assumptions used in the reanalysis of the COMS setpoint curve. Tables 1 and 2 provide peak RCS pressure from the mass and heat injection transients along with a description and timeline for sensitivity analyses performed for a PORV setpoint of 450 psig.
The other means of cold overpressure protection contained in our Technical Specifications include the RHR suction relief valves and a vent of 2 2 square inches.
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Each of these are sufficient to prevent an overpressurization event for the heat or mass (g
injection events described in the attachment.
We believe the attached information is responsive to your request. If you have any questions concerning this nformation, please contact us.
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/p>l Very truly yours, Alan C. Passwater Manager-Licensing and Fuels WEK/jdg Attachment 9803110046 980303 PDR ADOCK 05000483 P
PDR lllllllllWlllll!)llll]llllljllllIllllll e subsidiary of Amoren Carperstron
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o STATE OF MISSOURI )
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Alan C.
Passwater, of lawful age, being first duly l
sworn upon oath says that he is Manager, Licensing and Fuels (Nuclear) for 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
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therein stated are true and correct to the best of his knowledge, information and belief.
By /
ass Alan C. Passwater Manager, Licensing and Fuels Nuclear SUBSCRIBED a sworn to before me this dd day of 4 %nd 1998.
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M. H. Fletcher Professional Nuclear Consulting, Inc.
19041 Raines Drive Derwood, MD 20855-2432 Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive Suite 400 l
Arlington, TX 76011-8064 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Barry C. Westreich (2)
Office of Nuclear. Reactor Regulation U.S. Nuclear Regulatory Commission 1 White Flint, North, Mail Stop 13E16 11555 Rockville Pike Rockville, MD 20852-2738 Manager, Electric Department Missouri Public Service Commission P.O. Box 360 Jefferson City, MO 65102 Ron Kucera Department of Natural Reso_rces P.O. Box 176 Jefferson City, MO 65102 j
Denny Buschbaum
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TU Electric P.O. Box 1002 Glen Rose, TX 76043 i
Pat Nugent Pacific Gas & Electric Regulatory Services P.O. Box 56 Avila Beach, CA 93424
U Attachment ULNRC-3576 CALLAWAY COMS ANALYSIS AND SETPOINT DEVELOPMENT INPUT ASSUMPTIONS Callaway is currently analyzed for operation of a single centrifugal charging pump when COMS is enabled.
Union Electric requested that Westinghouse perform an analysis to determine the impact on RCS pressure overshoots assuming operation of the safety grade centrifugal charging pump plus a " normal" centrifugal charging pump. Revised setpoints have also been developed based on 20 EFPY Appendix G heatup and cooldown limits.
1.
Overshoots during the mass injection event are relatively insensitive to initial RCS temperature, but are limiting at lower RCS temperatures. An initial RCS temperature of 70F is assumed for the mass injection event.
2.
Reference 3 provides composite flows from the two pumps over a range of RCS pressures, assuming that both pumps are operating at full capacity. The analysis conservatively uses flowrates which were increased to 105% of the calculated values.
3.
In order to preserve the single failure criteria, one Garret Pressurizer PORV (Cv=48) is available to mitigate the transients. A signal transmission delay of.85 seconds and a stroke open/close time of 0.85/1.75 seconds are assumed. (The stroke close time has increased from the value of 1.05 seconds since the eriginal analysis was performed. Since the stroke close time does not impact peak pressurizer pressure, the assumptions and results of the previous analysis of record remain valid for the heat injection transient.)
4.
Setpoints are determined consistent with the methodology outlined in WCAP-14040, Rev. 2. In addition, ASME Code Case N-514, which permits a 10% relaxation of the Appendix G limits below the minimum acceptable COMS enable temperature of 200F,is also applied. The enable temperature is defined as the RCS temperature corresponding to a reactor vessel metal temperature less than the nil ductility temperature plus 50F (RTndt + SOF), or 200F, whichever temperature is greater.
5.
The RCS is assumed to be enclosed by a non-yielding, inelastic boundary, with the pressurizer water solid and at the same temperature as the reactor ccolant. This maximizes the pressure overshoots during the design basis transients.
6.
Setpoints are selected so that the Appendix G limit will not be exceeded down to the minimum reactor vessel bolt-up temperature of 60F.
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e Attachment ULNRC-3576 CALLAWAY COMS ANALYSIS AND SETPOINT DEVELOPMENT INPUT ASSUMPTIONS 7.
The setpoints conservatively account for the pressure difference (delta-P) between the wide range pressure transmitter and the reactor vessel limiting beltline region. The delta-P values used are as follows:
No. of RCPs Delta-P Operating (psi) 4 14.0 3
7.0 2
3.0 1
1.0 8.
Consistent with WCAP 14040, Ra 2, the setpoints include plant specific pressure and temperature uncertainties and temperature streaming effects. The pressure uncertainty calculated by Westinghouse is 85 psi. The temperature uncertainty calculated by Westinghouse is 16F, and includes 14F streaming effects.
i 9.
Where possible, setpoints are selected so that resulting pressure undershoots do not violate the pump seal limit. However, if a conflict exists between protecting the pump seal limit and the Appendix G.
j limit, protection of the Appendix G limit takes precedence.
10.
Setpoints are selected so that the gain of each segment between breakpoints does not exceed the
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function generator upper gain limit of 7.55 v/v.
I 1.
The steam generator tube plugging assumed in the COMS mass injection analysis is 10% steam generator tube plugging. Since lower RCS volumes generally result in higher RCS pressure overshoots, this assumption is conservative. For the heat injection event,0% tube plugging results in higher overshoots. Therefore, the previous heat injection analysis is conservative from the standpoint of determining setpoints which protect the reactor vessel.
12.
With regard to the heat injection case, the pump is started when the RCS is 50F lower in temperature then the secondary side of the steam generator.
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I Attachment ULNRC-3576 CALLAWAY COMS ANALYSIS AND SETPOINT DEVELOPMENT INPUT ASSUMPTIONS 1
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TABLE 1 l
LIMITING OVERSHOOTS FOR MASS INJECTION RATES
- l PORV MASS INJ LIMITING PEAK SETPOINT RATE OVERSHOOT PRESSURE (psig)
(gpm)
(psi)
(psig)
COMMENTS l
'350 684 56 406 NCP 100%
CCP 100%
4 450 "
635 50 500 NCP 100%
CCP 100%
550 620 47 597 NCP 100%
CCP 100%
750 594 42 792 NCP 100%
CCP 100%
Overshoots and peak pressures before application ofinstrument uncertainties and the delta-P.
Results of a sensitivity analysis (PORV setpoint of 450 psig and mass injection rate of 650 gpm) indicate that peak pressure occurs during the second pressure cycle. Mass injection begins at 2.0 seconds following steady state conditions in the RCS. The PORV setpoint is reached at 14.450 seconds. The valve begins to open at 15.3 seconds and is fully open 16.15 seconds into the run. Peak pressure is 501.4 psig at 15.6 seconds. The reset pressure of 430 psig is reached at 18.350 seconds.
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l Attachment l_
ULNRC-3576 i
CALLAWAY COMS ANALYSIS AND SETPOINT DEVELOPMENT INPUT ASSUMPTIONS i
I 1
TABLE 2 j
HEAT INJECTION COMPOSITE RESULTS
- RCS/SG PORY OVERSHOOT PEAK RCS TEMPERATURE (F)
SETPOINT(psig)
(psi)
PRESURE (psig) 70/120 450 14 464 550 14 564 650 14 664 4
100/150 450 21 471 l
550 21 571 l
650 21 671 200/250 550 48 598 650 48 698 750 48 798 300/350 550 50 600 650 50 700 750 50 800 l
Overshoots and peak pressures before application ofinstrument uncertainties and the delta-P.
l Results of a sensitivity analysis (PORV setpoint of 450 psig and RCS/SG temperatures equal to 100F/150F) indicate the following pressure trends: The pump i
is started 2.0 seconds following steady state conditions in the RCS. The PORV l
setpoint is reached at 23.182 seconds. The valve begins to open at 24.035 seconds J
l and is fully open 24.88 seconds into the run. Peak pressure is 471 psig at 24.2 seconds. The reset pressure of 430 psig is reached at 24.932 seconds.
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i Attachment L
ULNRC-3576 -
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CALLAWAY COMS ANALYSIS AND SETPOINT DEVELOPMENT INPUT ASSUMPTIONS l-g TABLE 3: Maximum Alkmable Function Generator Setpoints (Breakpoints)
Ihgh Setpomt Low Setpomt Breakpoint Number T-RCS (deg F)
(psig)
(psig) 1 60 501 471 2
'76 501 471 l
3 130 525 495 l
4 170 535 505 5
220 550 520 l
6 245 650 600 7
270 750 700 8
368 750 700 9
420 2350 2350 l
l Assumes that 0 RCPs are in operation for T< 100F i
and that 4 RCPs are in operation for T > = 100F l
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