ML19208C053
| ML19208C053 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/30/1979 |
| From: | Rebecca Stone OAK RIDGE NATIONAL LABORATORY |
| To: | |
| Shared Package | |
| ML19208C045 | List: |
| References | |
| NUDOCS 7909240466 | |
| Download: ML19208C053 (5) | |
Text
i Enclosurc 7 ii DP).TT
.I nssA.r.m 4/30/79 i
f Participatien in Three !!ile Island Calculations k
F R. S. Stone I
k
? ;. inning on the.
c f t e-the
.a!f,..mt m
." ' I v.t i t, ea r.o c very early discussions ith Ted Matt of TEC and Ecb liedrich of SAI.
The r
objective was to extrcpolate from fucI terperatures then being r.casured j
and so predict the tenperatures to be expected if the core cooling was
[
linited to natural cc-- rec: ion, k
b'orhin;; from dirensions in the T:!I PSAR, j.
Mott calculated the net buoycrt driving force nynilable as a result of r'
heating in the core end ccoling in the heat exchanger.
This was then equated to t! > frictional resistance to derive the flou rate and to determine the LT necessary to close the loop.
Sec sinplified representat ion in Fig.
1.
Difference between pressure in the two legs is Am q------45 ft f
l 45 01 + O2. 3 - 33 g - 12 ol + p lg 2
HE g
2
(
2 j
I 33 l(p1 + c2.
p-)lg = 33 (olo.,_)lg i
)
p,
=
}-----12ft q
.2 2
core g
)
1 7f 2
g 16.5 pl p2./
=
Ib /ft
O f
. p1 Fig 1 2
0.115 Ap lb /in,
=
f 1006 261 300ROPL81 Nil N
l I.
E 2
i i
t Li Ap 30 AT.
In the temperature and e
g BT pressure range rensured at the si.utdoun TMI, ao
.0436 Jb /ft 3
-=
F, so DT m
Ape 0.0436 AT, end
n 0.115 : 0.0436 AT = 0.00500 AT.
I Ted !M t ' r.,
I, e cc uuter cod which inclu:h the frictirn i
[
factor for the ent. ire leop for a typical B&U plant. Using tl.is, AP = 8.9 x 10 Q',
-6 9
I where Q is flew in _' bm/s ec.
Using this value for 6P in the reintion above, l
i n
Q',
Y or Q =
.C35
.i
-6
= 23.7 r1 8.9 x 10 In the core, poecr is added to the water at a rate
&=Qc AT.
P Again at TMI conditions, c
=1, and at a day and a half after shutdown, I
& = 10Mw = 9483 BTU /sec.
Equating the two expressions for Q, Q = 9483 = 23.7
\\bT T
t 2/3 9483 I
o AT = i
= 54.3 F (23.7j This is a manageabic temperature rise. With an intact core and an operational heat exchanger there should be no problem running on natural convection coaling at the 10 Mw level.
The concern is that the core may not be intact.
At the time of our analysis, thermocouples in one corner were indicating temperatures well above those of the rest of t'ae core. The fear of course was that the high temperature region had blockage and restricted flow.
P00RORBiEl.
1006 262
' t
(
.i.
r[
s t
F 3
i
!~
it At this point the group disbanded to realign with other discussion I.
,(
groups, nnd with Matt to continu, eniculations using a core percolation L
model in place of the core flow assumption.
I decided to try some further f
calc.:lat ione based on the assumptica of cuarter-core blockage.
The data L
{
-6 used b-1 Ted Mott give 0.512 x 10 for ti.= friction factor of the co o alone.
t i
g Uith 3/'. of the core completely bicched (in the extrera case) tre would expect i
to get 3/4 as much ficr for the sa.e t.P.
Since flo.: varies inversely with l.
the square root of the resistance, to chan;;e the flow to 3/4 requires 16
(
increasin; the resistance by 7, so I hree assuned a resistance of 16
-6
-6 j
x.512 x 10
.91 x 10 for 3/4 of c no mal core.
=
9 i
Uith one purp forced flow there is a AT of about 20 in the " undamaged" part of the core.
P 3/4 x 9483 lb So Q = _u_
6 d
=
20 AT sec u
i In the " damaged" part of the core, AT is about 160,
t i
P 1/4 x 9483 lb So Q
d d " AT-_
160 Ac
=
d Since both sections must have the same AP, i
{
2 2
R d d u
u'
-6
\\
u (\\,Q,/Q )l2 2
or R
=R
=.91 x 10 1 356/14.8 1
d t
d
}
)
N
-/
~
= 0.525 x 10
'l j
P00R OR8AA.
1006 263 8t.
i e.
t k,
t y*
4 t
tf g.
F.asistance for damaged and undamaged core sections in parallel in then l
-6 0.903 x 10 and for the entire circulation loop would be (8.9
.512 L
I
+.905) x 10
= 9.3 x IC~
As befor, f o r m- -
-tion co, ling
-6 2
.005 iT o 9.3 x 10 Q
and Q = 9433/AT, f
L So Q
=
or Q = 172 % / sec 3
E m
-6 (172) = 0.0269 psi
}
= 0.905 : 10 core LPc/.5:'5 x 10~
= 7.16 ]b / see Q
=
g i
P 47 d
=
= -
= 331 F d
7.16 d
Using 280 F as the inlet temperature prevailing at the time of the come
.a-tion, 331 F temperature risc vould exceed saturation temperature for the 1050 psi at which the core was then running.
For atmospheric pressure at the top t.
f of the loop, AT = 331 F would produce boiling in the damaged quadrant for ar
(
a inlet temperature.
e I
Since the region saowing elevated outlet temperature seemed to shift with changes in the choice of coolant pump, the assumption that part of the core is obstructed has been less defensible.
If the cause is simply inertial channeling, there should be no problem under natural convection.
Even if part of the core were obstructed to the extent calculated, AT will be proportional to power level. At a month after shutdown, if we assume 2 W afterheat, AT w uld be e31/5 = 66.2 F, a level which could be d
tolerated. There should be some concern over accuracy of AT in the hot spot 300RORBlWf=
06 264
'e
~
l i
'i i
I
(
5
[
region.
f As better measurements of temperature and flow become available
=g the above numbers would have to be modified; the methodology should be ok i
t ii k
t l
I i
r.
s I
O M
e P00R OMA 1006 265 ew e9 Q'