ML20248G241
| ML20248G241 | |
| Person / Time | |
|---|---|
| Site: | University of Michigan |
| Issue date: | 09/20/1989 |
| From: | Fleming R MICHIGAN, UNIV. OF, ANN ARBOR, MI |
| To: | Schumacher M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8910100147 | |
| Download: ML20248G241 (2) | |
Text
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D/Mlb NUCLEAR REACTOR LABORATORY i
THE UNIVERSITY OF MICHIGAN
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" phoenix Memorial Laboratory Ford Nuclear Reactor Ann Arbor, Michigan 48109-2100 (313) 764-6223 September 20, 1989 PRIORITY ROUTING I
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Martin Schumacher tpm--
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Nuclear Regulatory Commission
[ h-bh 799 Roosevelt Road Glen Ellyn, Illinois 60137 L
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+ ur FIttsb Re: Ford Nuclear Reactor pool Leakage
Dear Mr. Schumacher:
This is in response to your questions concerning pool leakage at the Ford Nuclear Reactor.
Almost since the initial commissioning of the reactor, we have had varying amounts of pool leakage through hairline cracks in the concrete and around penetrations through the concrete.
l periodically, we contract with a waterproofing company to seal the cracks.
We generally observe an increase in leakage following our prolonged Christmas season shutdown of two weeks.
pool cooldown during that period tends to open the cracks somewhat.
Approximately three months of routine operation following the Christmas period are required to seal the cracks and restore the leak rate to its normal, low level.
We are considering reactor operation for short intervals during the Christmas holidays to prevent pool cooldown and subsequent increased leak rate.
We routinely keep track of makeup water added to the pool and the pump down of sumps located in the basement of the reactor.
All building drains except toilets dump into these collection sumps which are then pumped to retention tanks where the water is sampled and filtered before it is pumped to the Ann Arbor sewer system.
The sumps in the basement collect pool leakage, but they also collect water from floor drains, air conditioning coil condensation, drinking fountain drainage, and sink drains.
Exact determination of pool leakage is further complicated by the fact that a large amount of water evaporates directly from the pool surface and a significant portion of the pool leakage, which forms a thin film on the pool wall outer surface, evaporates before it is collected in our sumps.
We performed experimental measurements of pool surface evaporation and arrived at an evaporation rate of 80 gallons per day.
Some years ago, we hired a consultant to evaluate the water usage on the North Campus of the University.
He used this standard: under normal circumstances, 20 percent of water intake to a building is lost to some form of evaporation while 80 percent is discharged to the sewer.
That does not apply directly to buildings with known evaporative processes such as cooling towers.
Based on that
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Ford Nuclear Reactor Martin Schumacher September 20, 1989 standard, we are assuming that 80 percent of our pool leakage is collected in our sumps and 20 percent evaporates.
The following table is a summary of pool water makeup, surface evaporation, and leakage for the most recent two quarters of 1989 and for a preliminary measurement we conducted from September 15-18, 1989.
The latter measurements will form the basis for a more accurate surveillance procedure we are preparing to implement which will eliminate the miscellaneous sources of water in the sumps mentioned above that obscure the true pool leak rate.
Losses Pool pool Leakage Surface Sump Evap-Pool Evaporation Collection oration Makeup Difference (gal / day)
(gal / day)
(gal / day) (gal / day) (gal / day)
Mar 1 -
Jun 1, 1989 80 109 22 216
+5 Jun 1 -
Sep 1, 1989 80 81 16 145
-32 Sep 15 -
Sep 18, 1989 80 55 11 145
-1 From the data, you can see that numbers for the first quarter, indicate makeup exceeded loss by 5 gallons per day.
For the second period, loss exceeded makeup by 32 gallons per day.
The variation in these numbers reflects the uncertainties in the measurements and the sources of water into the sumps.
The last measurement was more precise.
All sump drains except pool leakage were effectively secured.
Sincerely, j
% -F Ronald F.
Fleming Director Michigan Memorial - Phoenix Project-xc:
G.
Cook P.
Simpson Control Room page 2
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