ML18030B217
| ML18030B217 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/28/1986 |
| From: | Muller D Office of Nuclear Reactor Regulation |
| To: | White S TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8604070427 | |
| Download: ML18030B217 (4) | |
Text
March 28, 1986 Docket Nos.:
50-259/260/296 Mr. S.
A. White Manager of Nuclear Power Tennessee Valley Authority 6N 38A Lookout Place 1101 h1arket Street Chattanooga, Tennessee 37401
Dear h1r. White:
SUBJECT:
SECONDARY CONTAINMENT ISOLATION DAMPER CLOSURE TIh'IES Re:
Browns Ferry Nuclear Plant, Units 1, 2 and 3
,By letter dated January 23, 1986, you transmitted an Unreviewed Safety Question Determination (USQD) on the above subject and requested that we inform you whether we disagreed or concurred with your conclusions.
Since there are, presently no Technical Specifications requirements on closure times for the ventilation dampers in either the refueling floor zone or 'in the reactor zones, no change was being proposed as a result of the reanalysis.
Your reanalysis indicated that there would be an increase in the postulated radioactivity that might be released to the environment if the dampers in the zones remain open for 5 or 10 seconds after receiving a high radiation signal rather than closing in 2 seconds as stated in the FSAR.
The calculated effects of the accident would also be increased since some radioactivity would be released at the roof of the reactor building rather than being filtered through the standby gas treatment system and released from the 600 foot stack.
BS04070O27 860Saa PDR ADOCK 05000259 P
0 lf hi i
Mr. S.
A. White In accordance with our (Standard Review Plan, NUREG-0800, Section 5.7.4) criteria, the radiological impacts are not considered consequential if the calculated values are well within the exposure guidelines.
We have independently calculated the radioactive releases from a postulated fuel handling accident, assuming the radioactivity is exhausted (undiluted) by open ventilation ducts in the refuel floor area and exhausted through the roof vents.
The calculated radiation dose for exposure for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> was less than one rem to both the thyroid and whole body for a ten second damper closure time.
Since the calculated exposures are well within the NRC's acceptance criteria, your proposed revision of the FSAR does not constitute an unreviewed safety question.
Sincerely, cc:
See next page Daniel R. Muller, Director BWR Project Directorate ¹2 Division of BWR Licensing DISTRIBUTION:
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