ML19257A979
| ML19257A979 | |
| Person / Time | |
|---|---|
| Issue date: | 07/12/1979 |
| From: | Woods R Office of Nuclear Reactor Regulation |
| To: | Check P Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-16, REF-GTECI-SY, TASK-A-16, TASK-OR NUDOCS 8001140155 | |
| Download: ML19257A979 (5) | |
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MEMORAtlDUM FOR:
Paul S. Check, Chief, Reactor Safety Bran-h,
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Division of Operating Reactors
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FROM:
Roy Woods, Reactor Safety Branch, Division of Operating Reactors
SUBJECT:
TRIP REPORT, R. WOODS TRIP TO LYNN, MASSACHUSETTS, GE SECTOR STEAM TEST FACILITY (SSTF) TO WITNESS TESTS R. Woods, NRC/ DOR, witnessed two tests at the SSTF on July 5,1979 and discussed the SSTF experimental program with J. Leonard and J. Alai of GE.
Enclosed is R. Woods' trip report. No presentation slides were used.
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t Roy Woods Reactor Safety Branch Division of Operating Reactors
Enclosure:
As stated cc: See attached list 1745
.315 8001140 (
ENCLOSURE REPORT CONCERNING R. WOODS 7/5/79 TRIP TO WITNESS SSTF TESTS IN LYNN, MASS.
During the week ending 7/6/79, GE plans to complete all tests at the Lynn, Mass. Sector Steam Test Facility (SSTF) that are for the purpose of fulfilling GE's committment to determine steam effects on core spray distribution for BWR/6 design reactors.
R. Woods, NRC/ DOR, witnessed a typical single sparger and a typical double sparger SSTF test.
The following report presents his observations and impressions gathered at that time.
The SSTF facility appears to be very successful in producing the conditions it was designed to produce. That is, it can maintain a saturated steam environment in the desired pressure range, utilize spray water in the desired temperature range from either or both spargers, and accurately and reproducibly measure the resulting spray distributions. Achieving the proper conditions and collecting, recording and processing the necessary data appears to be a matter of routine; all procedures in.olved in cali-brating and running the SSTF appeared to have been carefully worked out ahead of time, and the data obtained appeared to be of highast quality.
Although final data reduction with all detailed corrections, etc. will be perforned in San Jose and a report will be issued to NRC in September 1979, preliminary indications are that the September report will present GE's confirmation of the hydraulic-and-thermodynamic-effects separability hypothesis, thereby confirming GE's proposed methodology for determining 1745 516
2 spray distributions in a steam environment for various BWR designs.
The present sparger configuration in the SSTF, which was utilized in the above discussed tests, is typical of a 218" I. D. BWR/6 plant. The spargers are above the core one to two feet. The top sparger has three types of nozzles installed, consisting of Spraco nozzles,1" elbows with nipples, and 1" open elbows, installed in alternating order on top of the top sparger. The lower sparger has Spraco nozzles, 3/4" open elbows, and 1" open elbows also installed in alternating order on top of the bottom Since all nozzles are installed on top of their respective sparger.
spargers, the upper sparger nozzles are separated from the lower sparger sozzles by a foot or more.
The next use of the SSTF is planned to be for spray distribution tests for a sparger geometry more typical of BWR/4 plants. BWR/4 spargers are much closer to the top of the core (the lower sparger is within inches),
the nozzle types are different (hollow cone "VNC" nozzles are used, along with other nozzles), and the upper sparger nozzles are mounted below the upper sparger causing them to be within inches of the lower cparger nozzles which are mounted on top of the lower sparger.
Following those tests, the facility will be utilized for Counter Current Flow i.imiting (CCFL) phenomena experiments to be jointly funded by GE, EPRI, and NRC.
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. The NRC witness (R. Woods) and the principal GE representatives (J. Leonard and J. Alai), discussed the following preliminary NRC potential concerns with the SSTF tests and results:
- 1) Since ECCS " Appendix K" calculations are done on an individual bundle basis, there is no justification for use of " radius average" core spray flows. The SSTF results would be unacceptable if pre-sented only in terms of radius average values; radius minimum values, or some equivalent, would be more justifiable.
- 2) Planned SSTF tests in steam with and without the "30 shroud" walls in place were cancelled due to schedule problems.
(The tests were run in air, however.) Lack of such tests in steam may nake it more difficult to quantify wall effects that could potentially be present in the final results.
- 3) Planned extended array tests (collecting water in bundles outside the 30 sector) were not run in steam or air.
Lack of such tests could make it more difficult to quantify wall effects that could potentially be present in the final results.
- 4) The NRC staff will not have reviewed the BWR/6 spray-distribution-in-steam SSTF test results before that configuration is removed (or its use discontinued) in the SSTF facility.
If additional testing is required as a result of NRC concerns, schedule delays and conflicts could result.
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' 5) The SSTF tests were conducted at a maximum pressure of 75 psia.
However, credit is taken for rated spray flow (and resulting cooling) in BWR/6 ECCS " Appendix K" analyses at 150 psia and below. This may cause some difficulty regarding justification of GE's spray distribution methodology at pressures between 75 and 150 psia.
- 6) The SSTF tests are providing new information regarding how much spray flow is available to the minimum-spray-flow channel.
- However, the other consideration is how much spray flow is needed to provide justification for the spray cooling coefficients assumed in the ECCS " Appendix K" calculations.
This subject should be given more attention, possibly through new low-flow FLECHT type tests (or better documentation of such tests previously run) particularly if the two-sparger SSTF test results demonstrate less spray flow margin than expected.
- 7) Some SSTF tests were conducted with relatively more steam introduced into the upper plenum compared to the fuel bundles than would be expected in a pcst-LOCA reactor, and with no steam at all in the SSTF facilities' bypass region. Although it can be argued that these effects produce conservative (lower minimum flow) results, it may be difficult to quantify the exact effects on the final results.
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