ML20147C834
| ML20147C834 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Browns Ferry |
| Issue date: | 12/13/1984 |
| From: | Clark R Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML082310192 | List: |
| References | |
| FOIA-87-728, FOIA-87-853 NUDOCS 8803030173 | |
| Download: ML20147C834 (8) | |
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WASHINGTON, D. C. 20656
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Docket No. 50-259 y1 y
LICENSEE:
TENNESSEE VALLEY AUTHORITY (TVA)
FACILITY:
BROWNS FERRY NUCLEAR PLANT, UNIT 1
SUBJECT:
MEETING WITH TVA - SINGLE LOOP TEST On December 13, 1984, we met with TVA in Chattanooca to work out.the details of a test program to evaluate the thermal-hydraulic stability of BWR as in the lower flow area of the power flow map.
For over four years, the NRR technical staff has had concerns regarding the stability-related aspects of single loop operation.
Because of these concerns, we have had I
applications for approval of sinale loop operation from ten BWR facilities which have been "on hold" for several years.
On February 10, 1984, General Electric Company (GE1 issued Revision 1 to SIL No. 380 as a result of new stability test data from a foreicn 8WR. The SIL provided "additional operating reconsnendations in the unlikely event that thermal hydraulic instability induced neutron flux oscillation occur" in the high power / low flow corner of the power flow man. As the SIL l
pointed out, "this region may be encountered during startup/ shutdown, during rod sequence exchanges and as a result of a recirculation pumo(s) trip event" - whether operating with one or both recirculation pumps. The tests referenced in SIL No. 380. Revision 1 were run on a foreign BWR-6 with a comparatively high power density (about 56 kw/ liter). Since the magnitude of the flux oscillations are related to power density, the instability would be expected to be less in a BWR-4 such as Browns Ferry with a lower power density (about 48.7 kw/1).
GE noted that SIL No. 380 was not applicable to BWR-3s such as Pilgrim 1 and Monticello because of their low power densities (less than 40 kw/1). Last spring, we had informally discussed with TVA the desirability of conducting a test of thermal-hydraulic stability at Browns Ferry Unit 1; our request was i
formalized by our letter of July 12, 1984.
In its response of October 11, 1984, TVA agreed to conduct a single loop operation test at Browns Ferry Unit 1.
TVA reauested a meeting with us and any involved consultants to work out details of the test proaram. This memo sumarizes the result of the requested meeting.
TVA was represented at the meetino by personnel from its fuels, RWR core design, enaineering analysis, reactor engineering, methods and licensing groups in Chattanooga and by reactor engineering and compliance staff from the Browns Ferry plant. TVA personnel had also discussed the test program with GE. The NRC was represented by the Core Performance Branch, the writer and three consultants from ORNL. A partial attendance list is enclosed as Enclosure 1.
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.. TVA had outlined a proposed test program which is enclos2d as Enclosure 2.
ORNL proposed a slightly different test program which T'4A agreed to conduct. TVA's position was that if the program suggested by ORNL would resolve whether or not there is a significant thermal hydraulic stability problem, this is what they would run. The agreed upon test would take data at seven points as shown in Enclosure 3, including one point on the 80% rod line.
Although TVA has the necessary recorders and eouipment for the test, ORNL indicated that they preferred that TVA use recorders supplied by ORNL. TVA aoreed to this arrangement. ORNL is to deliver the equipment to the site at least a week prior to the test. Although power will change by maybe 1%
to 2% during the test, ORNL prefers that control rods not be moved, but let the power level adjust where it will.
Browns Ferry 1 will reach the end of nominal core life about the end of March 1985. To have sufficient reactivity to conduct the single loop operation test, it will have to be run by mid-February 1985. TVA will have to prepare a test procedure and have it approved by Plant Operations Review Comittee (PORC). Considerable flexibility is needed in the test orocedures with respect to power levels, hold times, etc.; if the results were known, there would be no need to conduct the test. Tentatively, the test is scheduled for the first weekend in February. The alternate date is the weekend of February 9 - 10, 1985.
While TVA agreed to all aspects of the test program as suggested by ORNL and NRC, there was a major difference of ooinion on what the test prooram might accomplish. The position of NRR's technical review branch is that i#
the test shows no significant thennal hydraulic stability problem, the results would support single loop operation with the same restriction approved for Peach Bottom Unit 3.
TVA's position is that if there is no indication of a problem, this should support single loop operation without restrictions.
M R7 chard J.
lark, Project Manager Operating Peactors Branch #2 Division of Licensing
Enclosures:
As stated cc w/ enclosures:
See next nage
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DECEMBER 13, 1984 PROPOSED SINGLE RECIRCULATION LOOP FLOW TEST I
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112/13/84 Proposed Single Recirculation Loop Test Test to be performed on: BFNP Unit 1 January or February 1985 Data Signals to be recorded for_ analysis:
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1 APRM Signal 2.
3 LPRM Signal (at B level)
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3 1 LPRM Signal (at C level) lss-
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1 Active Loop Flow Signal 3-j 5.
1 Inactive Loop Flow Signal 6.
2 Jetpu=p Signals in Active Loop (double tapped) 7.
2 Jetpump signals in inactive Loop (double tapped) 8.
1 Core Delta Pressure Signal 9.
1 Reactor Pressure Signal Total of 13 signals to be recorded.
Length of time at each test plateaut i
13 Data signals recorded on magnetic tape (suitable for analysis by Oak Ridge) for 30 minutes at each test plateau.
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12/13/84' Test Plateaus: Minimum Test Plateaus TP1 - single pump, 50% power, c-1005 rod line
~ st-4 C TP2 - single pump, 30% power, -100% rod line A,... / # 4'7 en /o 'f? re,/ /,4e c e /* w ~ Yo % pe w n yo TP3 - single pump,,301 power,.4100% cod line Possible Additional Test' Plateaus:
TP4 - single pump,-60% power,6-1005 rod line TPS - single pump, 755 power,or100% rod line.
TP6 - Dual pumps, 30% power, <900% rod line TP7 - Dual pumps, 45% core flow, >^1005 rod line Milesstones to be completed:
12/13/84-1.
Finalize test requirements - obtain NRC/ORNL concurrence 2.
Write test procedure and attendant 10 CFR 50.59 review; PORC review and approval 3
Prepare test equipment 4.
Schedule test as load requirements permit 4
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