ML20206J403
| ML20206J403 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom, 05000000 |
| Issue date: | 12/13/1985 |
| From: | Owczarski P Battelle Memorial Institute, PACIFIC NORTHWEST NATION |
| To: | Jeffrey Mitchell NRC |
| Shared Package | |
| ML20204G644 | List:
|
| References | |
| RTR-NUREG-1150 NUDOCS 8704160087 | |
| Download: ML20206J403 (7) | |
Text
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OBallelle Pacific Northwest Laboratories P 0. Boi 999 Rahland, %ashingto-i S. A 99352 e* a 376-7900 December 13, 1985 Teles 15 2874 Jocelyn Mitchell U.S. Nuclear Regulatory Commission MS 1130SS Washington, DC 20555
Dear Jocelyn:
This letter summarizes my preliminary scoping calculations for molecular iodine (1 ) scrubbing in BWR pressure suppression pools.
2 The calculations (in part I following) of 1 DFs were made for the most 7
recent TC1 sequence in the draft Peach Bottom Report (BCL). Two methods were used:
- 1. SPARCB was modified (now SPARC-12) to include I., using gas phase mass transfer resistance only. This method is probably Qood for high pH pools.
- 2. 1 -pool equilibrium was assumed and equations supplied by 7
A.K. Postma (mo5ified for ionic solutions by PCO) were used assuming that no Cs0H was added to the pool and 22% of core inventory Cs0H preceded the 1
to the pool.
2 4
All iodine DFs for TC1 were greater than 10.
Thus 1 scrubbing appears to 2
be as good as that for large particles.
Additional calculations (in part II following) were made using SPARC-:2 and compared with experimental data obtained by Diffey, H.R., et.al., 1965.
International Symposium on Fission Product Release and Transport Under Accident Conditions, CONF-650407 (Vol. 2), pp. 776-804, " lodine Clean-Up in a Steam Suppression System" (copy attached).
SPARC-12 will be further adapted to include liquid phase mass transfer resistance and interfacial equilibrium.
The TC1 DFs will be recalculated then.
Please call me to discuss these calculations.
Sincerely ours, P.C. Owczarski, Ph.D.
Senior Research Engineer EARTH SCIENCES DEPARTMENT PCO:dh Enclosures l
l t
0704160087 870400 PDR NUREG 1150 C PDR hP
I..
IODINE DECONTAMINATION FACTORS FOR TC1 SEQUENCE The following information was obtained from Pete Cybulskis (BCL) for the TC1 sequence in the latest version of the Peach Bottom Report:
Core Inventory:
16.6 kg 1, 207 kg Cs, 23.3 kg Rb 2
Flow through X quenchers at 12 feet submergence.
70% of 1 and Cs deposit in primary system.
2 23% of 1 are captured in suppression pool.
2 22% of Cs are captured in suppression pool.
Time sequence of pertinent events:
TIME MIN EVENT FLOW RATES, LB/ MIN 134 CORE MELT BEGINS 177 H 0/23 H 2
2 166.6 CORE SLUMP BEGINS 170 END CORE MELT 1/14 172 END OF FUEL RELEASE 5/101 173 421/66 176 1000/7 230 BOTTOM HEAD FAILURE At head failure 1.3 kg 1 and 15.5 kg Cs remain in fuel.
2 The following assumptions were made to facilitate calculations:
1.
The fodine flow rate to the pool was constant at 6.44E-02 gmoles/sec between 134 and 172 minutes.
It was zero otherwise. This corresponds to 23% of 12 g ing to the pool.
2.
The pool was at 100'C, 1 atm.
3.
For the SPARC-12 calculations to be valid the pool must be at an adequately alkaline pH. At 100*C a neutral pool has pH = 6.1.
If 22%
of the core Cs and Rb are added to the pool the pH is 8.3.
4.
For the equilibrium calculations the two extreme pH values of 6.1 and 8.3 were used at the start of the iodine flow into the pool.
The following table is composed of pool pH and H values at various times during the fuel release.
I r
I
== - - -,
4 No Cs or Rb in Pool 22% Cs + Rb in Pool TIME pH H
pH H >
134 6.1 8.3
'a 140.4 5.95 614 8.3 9.7+06 150.3
'5.7 157 8.3 9.7+06 170 5.4 46 8.3
- 9. 7,t06 172 5.4 43 8.3 9.7+06 H = concentration of iodine in the liquid phase / concentration in the gas phase at equilibrium. The above values and SPARC-12 were used to obtain the plot of DFs for the TC1 sequence (Figure 1). All of the DFs for the entire sequence are very high. No attempt was made to obtain an overall DF.
When SPARC-12 finally has both mass transfer resistance in the liquid phase as well as interfacial equilibriums, then reruns of the TC1 sequence will probably give DFs lower than that of lowest curve in Figure 1.
The amount lower can only; be speculated. More precise Cs and I flow rates should be 2
used in place of those assumed here.
The next part (II) shows that the present SPARC-12 produces an acceptable upper bound on existing experimental data.
r
~.
II. SPARC-12/ DATA COMPARIS0N SPARC-12 with gas phase 1 mass transfer resistence only was run at the 7
range of conditions of the experiments of Diffey using the large (50mm) lute at 50 cm submergence. Figure 2 shows the results of these SPARC-12 calculations superimposed on a plot in the Diffey paper. The SPARC-12 DFs form an upper bound to the experimental data that is very close to the scrubbing data with sodium thioniltate present in the pool. This favorable comparison suggests that the SPARC-12 calculations of part I will also be an upper bound. Also, the slope of the SPARC-12 curve compares very favorably with the data. This suggests that the SPARC-12 model for steam condensation removal of I, is correct, i.e., the fraction of the gas volume condensed at the vent exit is the same fraction of 1 removed at that 2
point.
Figure 3 is a plot of SPARC-12 DFs as a function of pool depth with H, as carrier gas both with and without water vapor present.
Pool conditiohs are 100*C and 1 atm.
DFs with H are slightly higher than those one would p
obtain using air as a carrier gas.
+ EqulLLbrium DF, 22% core Ce0H Ln pool e SPARCI2 DF, HLgh PH A Equilibrium DF, no CaOH in pool 10"
.+
=
.y/
20-
.h.
i r
10' I
1 10' I
1 o
e g
e
- l 10' 1 :
I i
\\
i g
10' A- ---- -
r 1
ce.
2 g
o II I
1 E
A i
If r i
10' r
T 10' r
r 5 :
1d
~
r 10' 100 110 120 130 140 150 180 170 100 190 200 Time (ntn)
Figure 1.
Iodine DFs for the TC1 sequence.
'N h
- OW*
- omen 6 6wh h==.
=
.m e, -e um e oeam ese.w
s to.
'y i
i s\\ s
\\
s
\\
x X\\
\\
\\
k N 3
\\
s 10 s
x x
x s
N gX X
~
\\
8 x
N x
O s
N E
\\
b 2
10 E
\\X X
X
~
b 6
z O
D E
Sor.m
.A 0 g/l (SPARC-12) 4 3
10 2
Final concentration of lodine in pond water Lute dia g mol ? titre (x10 )
6 O
3mm X'
~
~
4 to 16 W
50 min a
O 50mm 4, 2 5 to 160 O-N/200 Na2 5 0 I" D0"d 2 3 I
I 1
i 01 10 10 100 AIR / STEAM - weight */.
REMOVAL OF ELEMENTAL IODINE FROM A STEAM / AIR MIXTURE BY MEANS OF A WATER LUTE.
FIGURE 5.
A.E.R.E.- R. 4 8 8 2.
Figure 2.
SPARC-12 data compared with experimental data.
~ _
SoLLd Lt.ne: No St.oom i
Dashed Lt.ne: 0.1 Moles Hydrogen / Mole Stoom 10"g 10" r 1
I
[
]
10' r i
10' r 1
.E i
10' r i
Es 18 r 1
E 1
=
It r
i
=
=
1(f r 1
10' r
1 10' r
1 10' 0.0 50.0 100.0 150.0 200.0 250.0 300.0 350.0 400.0 m.0 500.0 Pool Dept.h (cm)
Figure 3.
SPARC-12 0Fs with H2 as carrier gas.
-. -