ML19246A328
| ML19246A328 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/10/1979 |
| From: | Schierling H Office of Nuclear Reactor Regulation |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| TASK-TF, TASK-TMR NUDOCS 7906110310 | |
| Download: ML19246A328 (2) | |
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v MAY 101979
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Occket No.:
50-320 TiOTE TO:
Dennis Crutchfield Program Support Staff, iiRR FROM:
H. Schierling, Section A Accident Analysis Branch, DSE
SUBJECT:
THREEMILEISLAriD2-HYDROGE:1C0flTROLCAPABILITYIf. SIDE CONTAINMEtiT At about 9 a.m. on Saturday, March 30, 1979, the NRC staff at TMI-2 was advised that the hydrogen concentration inside the containment was 1.3%
at that time.
H. Denton requested that I detemine the method and time required to reduce the concentration to 1.0% and less.
I mide the following assumptions:
(1)
Hydrogen is removed from the containment by two reccd iners with a 100% efficiency and with a combined flow rate of F=lla cubic feet per minute.
(2)
No additional hyJrogen is generated or added to the containnent.
(a non-conservative and non-realistic assumption).
(3)
The hydrogen concentration is unifom throughout the containment.
6 (4 )
The containment net free volume is V = 2.1 x 10 cubic feet.
With these assumptions the hydrogen concentration is given by
-At C (t) = C e o
where 1, the removal constant, is
0.0732 day -I A
and the corresponding removal halftime is 8.05 days tr/.?=
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g-f,%Y 10 '973 The method and status of the hydrosen removal was deternined from an abbreviated FSAR available at the site and from contacts with the NRC staff and licensee personnel in the control room as follows:
(1) Two hydrogen recombiners, thermal units, skid mounted are available on the site.
(2) One unit was being installed at the time in the auxiliary building, the intake being connecte'd'to the containment purge line and the discharge to the' containment air. intake. The second unit, still in storage at the time, can be installed in parallel, (3) Because of the high radiation level of the containmeni, atmosphere, to be circulated through the recombiner(s), a lead shield was being erected around the first unit.
provisions for purging the unit with nitrogen were also being considered.
I advised H. Denton within about one hour of the above status and made the following additional comments:
(1) With only a single hydrogen recombiner operating the reduction time would double to 15 days, (2) Additional hydrogen.was introduced to the containment by the continued, intermittent venting of the pressurizer, This also increases the reduction time.
I recommended that the hydrogen concentration be monitored, as a minimum, on a daily basis.
(3) I recommenced that the licensee should inquire about and obtain additional hydrogen recombiner capacity for backup.
i The first hydrogen recombination unit was finally placed into operation during the afternoon on Monday, April 2,1979.
The hydrogen concentration was monitored at least once a day.
It increased to 2.4% during April 1, 1979.
H. Schierling, Section A Accident Analysis Branch, DSE R. Va,Uner cc:
Dist: /entraltiles PSS Reading File 228 051 AAS Reading File NRM Reading File b.A(3/f3E I
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