ML19306A013
| ML19306A013 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Ginna |
| Issue date: | 03/22/1984 |
| From: | Mattson R, Vollmer R Office of Nuclear Reactor Regulation |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19270C231 | List: |
| References | |
| NUDOCS 8404100054 | |
| Download: ML19306A013 (3) | |
Text
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EHCLOSURE
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NUCLEAR REGULATORY COMMISSION
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March 22,1994
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~b MEMORANDUM F0 W8T _ t ~
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E vision of Licensing FROM:
Richard H. Vollmer, Director Division of Engineering Roger.l. Mattson,' Director Division of Systems Integration
SUBJECT:
MEMORANDUM REGARDING EQUIPMENT RESPONSE DURING AMENDMENT TO MARCH 1.6, 1984 BOARD NOTIFICATION HYDROGEN BURN EVENT
Reference:
Memorandum from Robert T. Curtis, Chief, Containment Systems Research Branch, RES to Vincent 5. Noonan, Chief. EQB et. al. dated February 16, 1984 Electric Power Research Institute (EPRI) has recently completed hydrog:n burn equipment tests at the Nevada Test Site (NTS) as part of a jointly sponsored program with t.he NRC. The tests resulted in a number of failures -
and cable burning which had not been experienced in previous equipment tests conducted by NRC and Industry.
The referenced memorandum, which is attached, transmitted the visual observation performed by Sandia National Laboratory (SNL) on the l
equipment.
Since then, EPRI has also transmitted a "Second Qu'ick -
Look Status Report on EPRI Hydrogen Burn Equipment Tests (RP-2168-3)"
by memorandum dated February 17, 1984.
The purpose of the final two tests, conducted durirg the month of January,1984 was to demonstrate equipment operability in a large, dry containment during and after the hydrogen burn event for a 7E% metal water reaction (13% H with 30% steam).
A video cassette recording 2
of these experiments shows that some cable burned extensively, both during and after the hydrogen gas burn.
Post test visual cbservation of many of the cables revealed charring, crte ig, bulging and/or wrinkling of the outer cable jacket surroundi,.g the insulated conductors.
In some instances, splits were seen in the outer. jacket such that inner insulators were visible.
Importantly, however, there was no evidence of exposed tetal conductor; thus there is no basis at this time for concluding that the cable would not perform its function.
Unfortunatel.i, the cable was not energized during the test; thg3 it can not be conclud>d that the cable would have performed satisfactonly during the combustion event.
Post-test evaluation of the cable will include testing to measure its current carrying and insulation capabilitis.
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Darrell G. Eisenhut 2_-
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In adoMion to the cable burning, two to three items of equipment did not
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perform t?eir function during the experiment, and evidence of water condensatioA and construction material, e.g., metal filings, were found inside-the examined pressure gages.
However, no other evidence of damage was found on the examined pressure gages.
l There are a number of reasons why the observed damage indicated above f
4 may conservatively exceed the damage which may occur to essential equip-sent during a hydrogen combustion event in a large dry containment. As we noted, the above preliminary information was obtained from tests involving the ignition of a mixture containing 13 percent hydrogen. This mixture was selected to represent a bounding case for large dry contain-t ments wherein the hydrogen produced from a 75 percent cladding-water reaction is allowed to accumulate in the containment. There is a prob-i ability albeit indeterminate that the hydrogen will not accus.ulate to a i
13 percent concentration. This uncertainty is due to the presence of l
l native random ' ignition scurces insids containment, i.e., sparks from motors.
Such random ignition may result in combustion at e lower hydrogen l
concentration with resultant less severe consequences. -There was no 4
burning of cable opened in the video tapes of NTS tests at hydrogen concentrations less than 13 percent.
Another reason why the data'may not j
de an appropriate representation of the probable damage in a large dry containment is that the equipment including cables was not necessarily installed or physically arranged in a manner representative of actual i
plant conditions.
For example, the cables were simply looped over-scaffolding in the test vessel; the cables were not laid in trays which 1
would afford some protection. A last item to be noted is that the NTS i
facility had a relatively low spray capacity.
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These results from the burn tests at 13% M should not be applicable to i
7 the Mark I, Mark II, Mark III and ice condenseY containments.
Hydrogen 4
combustion will not occur in the Mark I and Mark Il containments as they are operated wih inerted containments. - Hydrogen combustion with rich mixtures, i.e., greater than 9 percent, in large volumes should not occur in ice condensers and Mark III containments because these containments are all furnished with specially designed hydrogen ignition systems to. assure 1
ignition in large volumes at lean mixtures, i.e.
less than 9 percent hydrogen.
In some other NTS tests of combustion of hydrogen at concen-trations lower than 13 percent, there were no obvious f ailures of" equipment i
'due to concustion, but there were some failures by other causes that are still being studied in laboratory testing 'of the specimens.
The extent of' applicability of these data to large dry containments and their safety significance are presently being evaluated.
In April of 1984 i
NRR and RES will examine the applicability of the NTS data for validating i
the HECTR computer code. The need for any further tests at large scale 1
and small scale will then be identified.
The final analysis of the NTS 1
data, to include such matters as the test water sprays, thL pnysical arrangements for the test specimens, and the er, a.- test examination of the i
damage to the specimens will require more tin.
'A expect to report on the such longer term evaluation by the end c.~ 1984 The implications of these j
evaluations on hydrogen rulemaking or individual, reactor licensing cases will be addressed on a case-by-case basis for the interim.
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Darrell G. Eisenhut ;
Pursuant to NRR Office Letter No.19, dated October 1,1982, we recommend that thic information be submitted for Board Notification for boards l
having,urisdiction over large dry containments. *
.J,.
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I s Rict.ard H. Vollmer Director j
Division of Engineering I
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,Roge J.
ttson,l Director t
Division f Systems Integration 1'As stated
Enclosure:
-cc:
H. Denton E. C;se R. C. DeYoung J. P. Knight T. Novak G. Lainas i
F. Miraglia V. Noonan R. Curtis B. Morris V. Benareya W. Butler K. Kniel
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R. LaGrange s
J. Larkins C. Tinkler K. Parczewski W. Farmer
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H. Garg EQ Section
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