ML19224A989
| ML19224A989 | |
| 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 | |
| NUDOCS 7906130381 | |
| Download: ML19224A989 (2) | |
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UNITED STATES O
NUCLEAR REGULATORY COMMISSION f, i
?_'.f..j WASHINGTON, D. C. 20555
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MAY l 01979 Docket No.:
50-320
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NOTE T0:
Dennis trutchfield Program Support Staff, NRR FROM:
H. Schierling, Section A Accident Analysis Branch, DSE
SUBJECT:
THREE MILE ISLAND 2 - HYDROGEN CUNTROL CAPABILITY INSIDE CONTAINMENT L
At about 9 a.m. on Saturday, March 30, 1979, the NRC staff at TMI-2 was c
advised that the hydrogen concentration inside the containment was 1.8%
at that time.
H. Denton requested that I detennine the method and time required to reduce the concentration to 1.0% and less.
j I made the following assumptions:
- 5 (1)
Hydrogen is removed from the containment by two recombiners with a 100k efficiency and with a combired flow rate of F=ll4 cubic feet per minute.
(2)
No additional hydrogen is generated or added to the containment.
(a non-conservative and non-realistic assumption).
(3)
The hydrogen concentration is unifonn throughout the containment.
6 (4)
The containment net free volume is V = 2.1 x 10 cubic feet.
O With these assumptions tN hydrogen concentration is given by
~^t I
C (t) = C e o
where A, the removal constant, is
-I
= 0.0782 day A -
and the corresponding removal halftime is 180 262 2
tr/2 =
= 8.85 days The time required to reduce the hydrogen concentration from C = 1.8% to o
C) = 1.0; is determined as I
t= In (Co/C ) = 7.b days i
A 79061303 8/
7
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. WY 101979 The method and status of the hydrogen removal was determined from an abbreviated FSAR available at the site and from contacts with the NRC y
staff and licensee personnel in the control room as follows:
(1) Two hydrogen recombiners, thermal units, skid mounted are available j
on the site.
(2) One c.7it was being installed at the time in the auxiliary building, the in*.ake being connected 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 containment 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.
1 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 z'
time would double to 15 days, (2) Additional hydrogen was introduced to the containment by the continued, intermittent venting of the pressuri'er. This also t
increases the reduction time.
I recommended tha. the hydrogen concentration be monitored, as a minimum, on a daily basis.
(3)
I recommended 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.
t The hydrogen concentration was monitored at least once a day..
It j
increased to 2.4% during April 1, 1979.
}
'k H. Schierling, Section A Accident Analysis Branch, DSL I
cc:
R. voliner
.t E. !
180 263 p,
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