ML19224D318

Notifies That Literature Review Has Been Completed & Technical Discussions Held Re Flammability Limits for Hydrogen & Oxygen in Nuclear Reactor Vessels.Discusses Safe Flammable & Detonable Limits

ML19224D318
Person / Time
Site:	Crane
Issue date:	04/03/1979
From:	Riehl W NATIONAL AERONAUTICS & SPACE ADMINISTRATION
To:	Zebrowski E NATIONAL AERONAUTICS & SPACE ADMINISTRATION
Shared Package
ML19224D231	List: ML19224D230 ML19224D318 ML19224D322 ML19224D338
References
NUDOCS 7907110358
Download: ML19224D318 (3)

Text

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i April 3,1979 Ed Zebrowski, Group Leader TO:

Technical Advisory S'apport for Three Mile Island Nuclear Power Plan'. Incident FROM:

W. A. Riehl

SUBJECT:

Flammability Li=2cs for Hydrogen and Cxygen in Nuclear Reactor Ves sels A limited literature review has been done, and technical discussions I'

held, v-ith several groups with expertise in the area of flammability of hydrogen in reactor vessels. Primary literature sources included:

(1) NACA Report No. 1383, " Survey of Hydregen Combustion Prop e rtie s, " I. E. Drell and s.

melles - Lewis Flight Propulsion Laboratory - 1957.

(2) " Hydrogen Flammability Data and Applicati n to PWR Loss of Coolant Accident, " WAPD-SC-545, Wes.;nghouse Corp.,

Contract AT-11-1-Gen 14 - September 1957.

(3) " Hydrogen Flammability and Burning Characteristics in SWR Contr.inments, "

3. C. Slifer and T. G. Peterson, Gene ral Electric Company Report No. NEDC-108012 - April 1973.

3 (4) Private experimental data from J. Sm:. ley, J. Conine, E. Vanerus, and D. Krommenhoek, April 2,1979, General Electric Cornpany, Knolls Atomic Power Laboratory, Schenectady, New York.

(5) Yeaw, J. S. anc Schnidman, L., "The Extinctien of Gas Flames,

by Steam, " A. G. A. Proc eeding, 193 8, pp. 717-745.

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(6) Zabetakis, M., "Research on the Combustion and Explosion Hazards of Hydrog~a-Water-Air Mixtures, " AICU-3 377, September 4, 1956.

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Persons con: acted include:

(1) Bob Tedesco, Nuclear Regulatory Cc=missien, B ethe s da, Maryland.

(2)

E. Venerus, J. Conine, D. Krommenhoek, and J. 5 niley, General Electric Company, Schenectady, New York. (Reference 4).

(3) Thomas G. Peterson, General Elec:ric Company, San Jose, Califo rnia. (Reference 3).

The consensus of recc= ended Hammabili:y limits for use in hydrogen / oxygen mixtures a: 1000 esi and 3000F is as follows:

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% by Volume Zone Evdrocen Oxveen Safe Safe Limit 4

6 Marginal (Upward flame propaga:icn)~

Flammable U.i:

8 6

Ha ard (Deflagration - stable i

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Detonable Limit 15 12 Detona: ion To be in a given ene above, both the respective hydrogen and oxygen limits must be e.iceeded. Some clarification of the limits and zones therein is as follows:

Safe Limit: Absolutely no fire hazard below these values.

Flammable Li..it: Mini..um cuantities recuired for sustained

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combustion or flame. Set.veen 4 and 8%

hydrogen is a marginal ene c : " gray" area, in which flames propaga:e upward and then extinguish, presenting a limited fire hazard.

Between the fla==ablo and detenable limits, stable combustion and ex:losion can occur in confined spaces. The shock wave pressure

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difference will normally be only about 5 to 3 :ime s acpos s the front.

However, this could cause significant damage.

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3 Detonable Limit:

Above the detonable limits, "high crder" explosions can occur, with shock wave pressure differences of 18-20 times or more in confined areas.

a These limits are for hydrogen and oxygen oniv, with no other gases present - as nitrogen, air, or water. Naturally their presence is beneficial to varying degr.ees on the limits above.

However, these limits are recommended to be on the con-servative side.

For exa=ple, in air at ambient temperature the Hammable limit for hydrogen may be raised to 9% and for detonation to 18%

l-In high water contents (50c*o), the Ca==able limit for oxygen rises to 7% and for detonation to 18%

It is to be stressed that the variation of these limits with the presence

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of additional gases is complex. Any deviations to the limits in the above table must be discussed with technical experts on specific individual case by case situations.

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7 W. A. Riehl Hydrogen Co =bustion Consultant National Aeronautics and Space Administration Marshall Space Flight Center, AI., 35812 5

7 Mmhng Code: EH31 Phone: (205)-453-3532

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