ML20058J238
| ML20058J238 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 08/05/1982 |
| From: | Vincent R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-06-03, TASK-6-2.D, TASK-6-3, TASK-RR NUDOCS 8208090208 | |
| Download: ML20058J238 (4) | |
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Consumets Power company oeneral offices: 1945 West Parnali Road, Jackson, MI 49201 * (517) 788 0550 August 5, 1982 Dennis M Crutchfield, Chief Operating Reactors Branch No 5 Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT - SEP TOPICS VI-2.D, MASS AND ENERGY RELEASE FOR POSSIBLE PIPE BREAK INSIDE CONTAINMENT, AND VI-3, CONTAINMENT PRESSURE AND HEAT REMOVAL CAPABILITY Enclosed are preliminary Consumers Power Company comments to the NRC's letter of June 10, 1982 which submitted the staff's draft evaluation of SEP Topic VI-2.D, and VI-3, for the Big Rock Point Plant. The review that generated the attached comments was not complete due to a lack of information in the TER.
In order to conduct a thorough review of the staff's evaluation, the following information is requested from the staff's contractor, Lawrence Livermore National Laboratory (LLNL):
1.
Listing of RELAP input 2.
Listing of CONTEMPT input 3.
Calculations, assumptions and methodologies of post-blowdown mass energy release rates.
In light of the discrepancies between analyses performed by Consumers Power Company and LLNL, it is our judgment that a more comprehensive review is I
warranted.
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- E/CT l '
W Robert A Vincent Staff Licensing Engineer CC Administrator, Region III, USNRC NRC Resident Inspector-Big Rock Point pages I
.b oc0782-0028bl42 8208090208 820805 PDR ADOCK 05000155 P
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CONSUMERS POWER COMPANY BIG ROCK POINT PLANT COMMENTS TO TECHNICAL EVALUATION REPORT SEP TOPICS VI-3 AND VI-2.D i
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Consumers Power Company Comments to NRC Draft Evaluation of SEP Topics VI-3 and VI-2.D Big Rock Point Plant Page 6,1st Paragraph - With regard to using the MSLB peak temperature as EEQ criteria the following two comments apply:
1.
As pointed out in Ref (2) of the SER, the time that the atmospheric temperature is greater than 235*is not believed to be sufficient to heat containment electrical equipment to greater than 235!
2.
The duration at temperatures above 235'will actually be less than the 90 secs reported in Ref (2). This is because for that analysis 50 gpm of containment spray was assumed. However, according to Table 1 of Appendix C of Ref (2) the containment spray flow will be more than double that value - about 120 gpm split between the inside and outside of the steam drum cavity.
Page 7, Figure 1 Page 8, Figure 2 The values on the curve stay high for too long of a period.
There appear to be two reasons for this. First, heat sinks were not modeled; thus their effect is neglected.
Second, it is not clear that the post-blowdown energy was added properly to the containment. Before this curve can be adequately reviewed it will be necessary to look at the CONTEMPT deck as well as the method used to calculate post-blowdown energy addition.
Page 9, Figure 3 A comparison with the CP Co MSLB results show that the peak pressures and temperatures are not substantially different.
However, the values at any given time differ significantly.
For the long term, the values in Ref (2) are less than those plotted in Figure 3.
Appendix A, page 2, last paragraph, last sentence The secondary side of the emergency condenser is vented outside the containment, not inside as implied.
Appendix A, page 4, 1st full paragraph, second last sentence It should be made clear that only the very large breaks result in containment temperatures exceeding design, and then for only a short period of time.
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Appendix A, page 4, 1st full paragraph, last sentence In breaks of flow less than 52 lb/see operator action is required to trip the reactor only. The sprays will automatically initiate in sufficient time to keep the containment temperature below 235*.
i Appendix A, page 5, 1st full paragraph It is not correct to say that for all breaks less than 75 lb/sec the containment temperature will rise'to 335*and remain there indefinitely if only manual reactor trip at 600 secs is assumed. For breaks less
.than 52 lb/sec manual reactor trip at 600 sec is all that is required to keep the containment temperature below 235*.
This is because with reactor trip the containment isolates and the pressure reaches the spray setpoint in sufficient time to keep the temperature below 235'.
For break flows between 52 lb/sec and 75 lb/sec l
the temperature in the containment rise above 235"briefly.
However, the sprays will actuate once the containment pressure reaches-2.2 psig and this will cause the temperature to drop.
Appendix A, Table 5 2
Forheatsink/l2theareashouldbe40,711ft 2
not 24,744 ft t
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