ML19347C241
| ML19347C241 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/23/1980 |
| From: | Catton I Advisory Committee on Reactor Safeguards |
| To: | Savio R Advisory Committee on Reactor Safeguards |
| References | |
| ACRS-CT-1272, NUDOCS 8010170084 | |
| Download: ML19347C241 (2) | |
Text
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M ?*L wT-July 23,J)SD y
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R. Savio b
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I. Catton, N 'I -
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SUBJECT:
Hydrogen cg At the Sequoyah subcommittee meeting on/ July 1980, hydrogen problems were addressed.
I believe the applicants presentation demonstrated a lack of preparedness. Many questions that were asked could have been answered if they would have done their homework seriously.
Concerns I have are generic and not directed specifically to Sequoyah. Some brief comments resulting from the presentation are as follows:
1.
Hydrogen sensors Where should hydrogen sensors be placed and why?
What is the sensitivity of hyorogen sensors to temperature, pressure and steam?
2.
Arguments against inerting The only arguments I have heard against inerting were those presented by GE at the April 1 and 2 sbete meeting on the task action plan. The presentation was weak.
If there are sound reasons for not inerting, I would like to hear them. Those presented by GE were not convincing.
3.
Hydrogen Ignition Spark plugs are unreliable when the hydrogen concentration is less than 8%. They only become sure when the concentration is greater than 12%.
The detonation limit is 17%.
The sprays could act as quenchers.
Discussion seems, however, to evolve around fog with 500u o. ops and droplet concentration of.05% by volume.
Containment sprays appear to generate larger drops. Their capability seems to not have been exploited.
4.
Hydrogen distribution A number of physical processes could con.riste to non-uniform hydrogen concentrations in the containment.
For example, the ice condensers take out the steam and exhaust a cold mixture of hydrogen and air to the upper deck. The cold air will collect near the floor unless special effort is taken to mix it. Stratified flows are known for their resistance to mixing. Skimers would not he10. A serious look at post-accident flow patterns in a containment building is needed if the hydrogen problem is to be argued away. Dry containments have the reverse problem in that hydrogen will collect in high places. The suppression pool of a BWR could coll ect hydrogen.
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