ML20052C879
| ML20052C879 | |
| Person / Time | |
|---|---|
| Site: | 05000113 |
| Issue date: | 04/30/1982 |
| From: | Nelson G ARIZONA, UNIV. OF, TUCSON, AZ |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8205060052 | |
| Download: ML20052C879 (2) | |
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THE U NIVE RSITY OF ARIZ O N A p
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TUCSON, ARIZONA 85721 g
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April 30, 1982
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Mr. James Miller, Chief Standardization and Special Projects Branch U. S. Nuclear Regulatory Commission Washington, D.C. 20555 RE: License R-52 Docket 50-113 Correction in previously submitted Safety Analysis Report and Technical Specifications
Dear Mr. Miller:
This is to inform you of a difference between the Safety Analysis Report previously approved and the "as built" condition for the flow rate of the filtered stack fan for this facility.
On pages 25 and 27 of the Safety Analysis Report, the flow rate of the filtered stack fan is identified as 1,250 cubic feet per minute.
On page 27, a calculation is made to determine the total exposure dose of a person standing in the unmixed exhaust in the event a TRIGA core with saturated activity of fission products from continuous operation at 1000 kilowatts were decladded. This calculation was highly conservative for this facility, in that our maximum licensed steady-state power level is 100 kilowatts, and our average power is approximately 1 kilowatt when averaged over one year.
Accordingly, the dose rates calculated from this assumed fission product activity are high by a factor of 10 to 1000. Because of this low power level and duty factor, even with only air cooling, our fuel cennot develop temperatures great enough to lose clad, so the calculation is doubly conservative.
In the calculation, it is shown that the integrated dose is inversely pro-portional to the stack flow rate.
Our measurements show that the stack flow rate through the filter is approximately 500 cubic feet per minute.
This would increase the projected dose rate by a factor of about 2.5.
Since the actual licensed power 1cvel would reduce the projected dose rate by at least a factor of 10, the validity of the safety analysis is not compromised.
Accordingly, it is requested that the value of about 500 cubic feet per minute be substituted for 1,250 cubic feet per minute.in the Safety Analysis Report.
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I IPage 2 In reviewing the facility Technical Specifications, we have noted that the free-volume of the reactor room is specified as 10,000 cubic feet in 5.2(b).
The free : volume of this room is 6,500 cubic feet; connecting rooms in the facility 'have an' additional volume of 4,900 cubic feet. Due larger volume
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was apparently intended' to represent the. volume of the reactor room plus one of:the connecting rooms whose door is open during reactor operation.
However, the door to this room might be closed in an _ emergency, so its volume should not be included with the reactor room.
l On page 24-in lth'e Safety Analysis Report, it was assumed that the air volume available for dilution of gaseous fission products was 9,500 cubic feet 8
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(2.7 x 10 c,s). The smaller. room volume of 6,500 cubic feet (1.84 x 10 cm )
would increase the~ dose rates calculated in the room by approximately 50 percent. ~ However, as noted previously, thesefdose rates assumed 1,000 kilowatt continuous operation,. and are high by a factor of 10 to 1,000.
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Including the corrected stack fan flow rate a.d corrected room volume would increase the dose' rates by a factor of 3.75 while the corrected fission product inventory would decrease'it by a factor of 10 to '1,000.
Thus, the dose rates projected from recalculation would range from 0.375 to 0.00375
' times the previous dose rates in the Safety Analysis Report. Accordingly,.
4 it is requested that the Safety Analysis. Report, page 24, and-Technical Specification 5.2(b) be changed to reflect the_true reactor room volume of 6,500 cubic feet.
j Sincerely yours, _
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George W. Nelson, Director i
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