ML19221A592
| ML19221A592 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/08/1979 |
| From: | Hurley J INDUSTRY ADVISORY GROUP |
| To: | |
| References | |
| OSP-790408, TASK 107, TASK-107, NUDOCS 7905230266 | |
| Download: ML19221A592 (3) | |
Text
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Milt Levenson Date: April 8, 1979
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Subject:
Rc= oval of Airborne from:
J. L. Ikirley Radioactivity From Containment Of:
TMI-IAG Copy:
J. W. Thiesing Recovery fro.s the THI-2 incident includes reduction and eventual re::. oval of air-borne radionuclides from containment. The potential for malfunction of the con-tainment or its appurtenances, however slight, also necessitates for=ulation of a plan for protection of the public from this activity. lience outlined below are several ccacepts for re= oval of airborne activity from the building.
Assu=ptions 1.
Re= oval is intended primarily to protect the public.
Reduction of equipment exposure is not a criteria, although it certainly is a secondary effect.
2.
Deliberste atte= pts to reduce airborne activity may not begin until about 30 days after the incident, except for e=ergency actions.
t 3.
Cost is not a nsjor consideration.
Re= oval of Activity Prior to 30 Days After the Incident
.)
This concept is based on the pre =ise that the most significant noble gas contributors are xenon isotopes.
The system will also re=ove some iodine, krypton, and particulates.
The system would use recirculation through pressuri:ed charcoal at ambient terperatures.
It would be operated as follows:
(1) Using a 6 to 8 inch line from contain=ent. co2 press the effluent to about 150 psig and cool it to about 950F.
(2) After cooling, reduce streau pressure to 75 to 100 psig to lower its relative humidity, f"*'4 (3)
Without further reduction of pressure or temperature,,the stream through a large, long charcoal bed.
It is estimated that many tons of charcoal filling an approximately 6 feet diameter, 20 feet long tank would be used. This charcoal bed would be used until xenon breakthrough is observed.
(4) Return the process stream to containment.
s Equipus-nt would be expected to include:
(1) Orie ecmpressor rated in excess of 150 psig and 2000 fm with an after cooler capable of reducing stream temperature to 95oF. 6 b - d U nn I
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A pressure-reductica station' capable of dropping 2000 fu from 150 psig Q.
to 75 psig.
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(3) A 6 feet diameter, 20 feet long tank filled with charcoal.
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(4) 6 to 8 inchco piping, valves,and penetrations rated at about 200 psig.
It is believed one bed of charcoal would remove the xenon activity in about Ih days of recirculating.
It would also recove so=e iodine and krypton, and act as a filter to remove particulato activity.
Further design would address if the charcoal bed needs to be coo' ed.
Chilling of the stream is not included to~ avoid the need for equipment to remove H O and CO 2
2 Removal of Activity After 30 Days After the Incident l
The scheme takes into account that by 30 days after the incident the only significant noble gas activity is'due to Ir85 The system uses charcoal at low temperature with the effluent released to the atmosphere.
It would be operated as follows:
(1). Using a 200cfm blower, force the process stream through dessicant
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dryers and possibly a CO2 freeze-out heat exchanger.
(Detailed design woula determine the need for the' heat exchange @.)
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(2)
Force the stream through a tank of charcoal bathed in liquid N3 to bring its temperature to -1000F.
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(3) Release the output of the charcoal tank to atmosphere.
Equipment would be expected to include:
1.
One low pressure blower rated at about 200cfm.
2.
Dessicant dryers 3.
Possibly a CO2 freeze-out heat exchanger i
,4.
1 - 2 feet diameter tank full of charcoal. Tank length and liquid N2 requirements to be determined during engineering.
This system would be operated until Er85 breakthrough is detected.
It is 8
believed that most, if not all Kr 5 activity would be retained in the charcoal.
Another scheme for long term activity re= oval would be to bubble effluent from the containment through an organic solvent and back to containment.
It is felt that the solvent would retain the activity; however, this concept is =uch more i
theoretical with possible exposures as yet unexplored.
Iodine and Particulate Renoval Since an accidental release in the near future would contain signifIcant quantities of iodine 'and particulate activity, it may be worth censidering installing a system now to begin cleanup of these radionuclides.
2 or 4 inch deep trays could be coup 2ed with an upstream HEPA filter in a recirculation loop.
Removal rate is felt to be approximately proportioned to flow rate.
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It mist be emphasized that all thelbove are conceptual in nature with detailed
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i engineering yet to be performed. We esti::tr.te that such engineering would take j
about three days. The concepts might also be useful in reducing gas decay tank activity and for, total content.
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