ML20035E814
| ML20035E814 | |
| Person / Time | |
|---|---|
| Site: | 05200004 |
| Issue date: | 03/30/1993 |
| From: | Levin A Office of Nuclear Reactor Regulation |
| To: | Appajosula Rao GENERAL ELECTRIC CO. |
| Shared Package | |
| ML20035E810 | List: |
| References | |
| NUDOCS 9304190279 | |
| Download: ML20035E814 (2) | |
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WASHINGTON. D.C. 20555 March 30, 1993 Dr. Atam S. Rao General Electric Company 175 Curtner Avenue San Jose, CA 95125
Dear Dr. Rao:
Enclosed for your information is a list of questions regarding SBWR PCCS and IC separate-effects tests in the " PANTHERS" facility at SIET Laboratories.
The questions conform generally to the topics on the meeting agenda, and are meant to serve as focal points for our discussions on thcse tests on April 23.
These questions are being sent under separate cover by Mr. Michael Cullingford to SIET.
The questions are not meant to be forcal Requests for Additional Information, and it is not necessary to prepare formal written responses for transmittal to the NRC.
Please let me know if you have any questions about this transmittal.
Sincerely yours,
/-
lan E. Levin, x Senior Reactor Engineer Advanced Reactor Systems Section Reactor Systems Branch Division of Systems Safety and Analysis Office of Nuclear Reactor Regulation cc:
M. Malloy Enclosure 9304190279 930413 PDR ADDCK 05200004 A
o.
1 s
Questions for SIET GE testing in PANTHERS I.
Please describe the facility designs for the PCCS and IC testing.
2.
A brief description of the test programs was presented at the ICONE-2 conference in March, and additional information is contained in other documentation received from GE.
From the information presented on the PCCS tests, it appears that it will be difficult, if not impossible, to run transient tests on the heat exchanger, since the air and steam are metered into the HX inlet. While these steady-state tests may cover the range of parameters expected during system operation, they do not capture the essential cyclical behavior of the system in the plant:
efficient condensation at the beginning of a cycle, then a gradual build-up of non-condensible gas, which degrades condensation, and a resultant increase in drywell pressure that ultimately pushes the non-condensibles through the vent line to the wetwell, clearing the HX and returning to the start of the cycle again. Why can't the air and steam be mixed in a tank, similar to the way in which the IC tests are to be run, so that the system behavior and the header gas distribution are more typical of plant conditions?
3.
The initial condition of the IC system in the plant includes e rather long column of cold water that is prevented from entering the RCS by the closed return line valve. When the system is put into operation, it would appear that a potential exists for (a) water hammer and (b) thermal stress of the return line nozzle as the cold water enters the reactor vessel. Both of these phenomena would appear to have the potential to degrade system response.
How will they be measured and analyzed?
4.
The tests for both the IC and PCC HXs appear to call for steady-state pool conditions, with both temperature and level maintained approximately constant.
If one considers the operating conditions for these HXs, however, it would appear that the heat exchanger performance as the pool boils down is of significant interest, as is pool thermal behavior (stratification, mixing, etc.). The systems codes used to predict plant behavior may well need models based on or validated using data on those very parameters.
Please address why no tests involving either pool boil-down and/or stratification are included in the preliminary test matrices, to allow characterization of heat exchanger performance as a function of pool level and temperature distribution.
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