ML19329D497
| ML19329D497 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 10/15/1974 |
| From: | US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML19329D496 | List: |
| References | |
| NUDOCS 8003090122 | |
| Download: ML19329D497 (1) | |
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310-1 iggg 310.0-ACCIDENT ANALYSIS 310.1 Your response to question 6.2.24 does not address the (6.2.24) ability of the emergency ventilation system to pull down the annulus to negative pressure nor does it provide the details and sensitivity of the pressure tests to be conducted on the annulus volume as was requested. Provide this information.
310.2 1.
We have reviewed Section 15.4.8 (revisions 1 and 3)
(15) and the response to question 15.4.4 with respect to chlorine protection against the provisions in.
It appears that adequate protection for control room occupants against chlorine has been provided with the exception of the requirement for a bottled air supply for breaching apparatus.
In this regard indicate how you will meet the bottled air provision as described in Enclosure 1.
2.
Section 15.4.6.6 (Revision 1) states that the analysis of the effects of a turbine room steam-line rupture on control room habitability is in progress.
The analysis or its results are not apparent in the PSAR revisions to date.
Indicate when the analysis will be completed.
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PROVISIONS FOR ADEQUATE PROTECTION AGAINST A CHLORIME RELEASE Adequate protection of the control room against an on-site chlorine release will be achieved if provisions are included in the plant design to isolate the control room automatically.
to limit the potential build-up of chlorine within the control room, and if equipment and procedures are provided to assure immediate use of breathing apparatus by the control room operators.
Similar precautions would help mitigate consequences of most postulated toxic gas releases.
To accomplish the automatic isolation quick-response chlorine detectors should be located.in the fresh air inlets to the control room.
These detectors should be able to detect and signal a step increase in chlorine concentration within a time period not to exceed 3 seconds.
The detectors should be capable of signaling a step increase from zero to 15 ppm of chlorine by volume or greater. Detectors should be provided at the control room fresh air inlet for all plants that
~have storage facilitics that might accidently release a total of 500 pounds of chlorine. Additional detectors should be provided at
. chlorine storage locations that are less than 100 meters from the control room or that may release more than 3 tons of chlorine as a result of any postulated accident. These detectors should be placed, and the detector trip point adjusted, so as to assure detcetion of a leak or a container rupture. Detector trip signals should initiate automatic isolation of the control room and provide an audible alarm to the operators.
The means used to initiate automatic isolation should meet single active failure and seismic criteria.
Control room isolation should be accomplished within about seven seconds after detector trip. Adequate isolation requires all openings to the control room to have low leakage characteristics.
This would include doors, dampers and penetrations. Total in-filtration into the isolated control room should be less than 100 cfm assuming-a 1/8" water gage pressure differential across all openings and the maximum cperating differential across the isolation dampers upstream of recirculating fans. This leakage limit should be reduced to 25 cfm if chlorine storage is within 100 meters of the control room or if more than 3 tons of chlorine can be released as a result of any postulated accident.* Normal fresh air make-up should be limited to no more than 1 to 1 1/2 air changes per hour.
An administrative procedure should provide all doors leading to the control room be kept closed when not in use.
- These leakage rates are based on a control room volume of 100,000 cubic feet and thus should be adjusted as directly proportional to actual control room volume.
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