ML19340C945
| ML19340C945 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/11/1980 |
| From: | Saha P BROOKHAVEN NATIONAL LABORATORY |
| To: | Padovan M Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8012180310 | |
| Download: ML19340C945 (2) | |
Text
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BRCCKHAVEN NAilCNAL LSEOPATORY ASSOCIATED UhiVERSITIES. INC.
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December 11, 1980 Mr. Mark Padovan Operating Reactors Branch No. 4 P 330 Division of Licensing Office of Nuclear Reactor Regulation U.S. N'fclear Regulatory Commission Washington, DC 20555
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Dear Mr. Padovan:
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Subject:
Overcooling Transient in Rancho Seco Plant on March 20, 1978 I rentioned to you recently that we are engaged in analyzing overcooling transients in PWR's for the Analysis Development Branch of NRC/RES. Since the Rancho Seco plant went through a " severe" cooldown transient on March 20, 1978, ue are very much interested in simulating that transient by using the TRAC code. We have already gone through some infomation that was available to us. However, we have not been able to locate a number of specific details that are required to simulate this particular transient. Your help in this regard would be greatly appreciated.
The specific details or boundary conditions that are needed as function of time are:
1.
The initial boron concentration in the core, and the boron concentra-tion in the water injected by the HPI system.
(This information is not required if the reactor power vs. time can be provided.)
2.
The HPI flow rates and temperature during the entire transient (0 - I hr.).
3.
Steam / water flow rate out of the primary system via RCS safety relief valve. There are indications that the safety valve was alternating between the open and the closed positions (simmering) during the transient.
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December 11, 1980 Mr. Mark Padovan Page 2 4.
The main feedwater flow rate and temperature during the entire tran-sient. Also the distribution of feedwater between the A and B loop steam generators is needed.
5.
The auxiliary feedwater flow rates to the individual steam generators in Loops A and B for the entire transient. The auxiliary feedwater temperature, if substantially different from the ambient, is also needed.
6.
The steam flow rate out of each steam generator as a function of time.
Alternatively, the steam generator secondary side pressures can be used.
7.
The steam flow rates out through the steam safety valves in the secondary side.
It should be noted that the first three items are related to the primary side, whereas the last four items are concerned with the secondary side of the NSSS. If some of the items were not recorded during the transient, your suggestions regarding how to estimate those parameters would be appreciated.
Should you need any further clarification, please do not hesitate to call me. Thank you for your anticipated cooperation.
Sincerely yours,
.t Pradip Saha, Leader LWR Code Assessment & Application Group l
PS:jm l
cc:
S. Fabic, NRC/RES l
N. Zuber, NRC/RES l
F. Odar, NRC/RES l
M. Taylor, NRC/RES R. J. Cerbone, BNL U. S. Rohatgi, BNL l
J. Jo, BNL l
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