ML20206J368

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Discusses Latest Calculations of Molecular Iodine (I2) & Organic Iodide (CH3I) Scrubbing During TC1 Sequence from Draft Plant Rept
ML20206J368
Person / Time
Site: Peach Bottom, 05000000
Issue date: 01/15/1986
From: Owczarski P
Battelle Memorial Institute, COLUMBUS LABORATORIES
To: Jeffrey Mitchell
NRC
Shared Package
ML20204G644 List:
References
RTR-NUREG-1150 NUDOCS 8704160080
Download: ML20206J368 (3)


Text

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g,g OBaneHe Pacific Northwest Laboratories P.O. Bon 999 Richland, Washington U.5A 99352 wee ne m 376-7900 January 15, 1986 Telen 15 2874 Jocelyn Mitchell U.S. Nuclear Regulatory Commission MS 1130SS Washington, DC 20555

Dear Jocelyn:

This letter discusses my latest calculations of molecular iodine (I3) and organic iodide (CH I) scrubbing during the TC1 sequence from the draf t Peach Bottom rep $rt.

SPARC-12 was upgraded to include 1 mass transfer resistance in the 7

liquid phase and to include appropriate liquid-gas phase interface equilibria. A rigorous model for CH 1 scrubbing was also added. The 3

calculations were made with this upgraded version.

The enclosed figure 1 shows the results of the calculations. The topmost curve is the instantaneous DF for 1 where the Cs0H was allowed 9

to enter the pool concurrently with the 1 as specified by BCL. The 7

middle curve shows the DF for 1 where the Cs0H was not allowed into the 9

pool. The bottom curve is for CH 1, which exhibits very poor scrubbing 2

in hot pools.

The corresponding time / flow integrated DFs (total iodine flow into pool / total iodine flow out of pool) were 4.9E+10, 280, and 1.1, respectively.

The pool pH and pool 1 inventory are the most important parameters in 7

controlling 1 DF. The following table contrasts the pool pH during the 7

period of fission product iodine flow into the pool for the two cases.

Note that a neutral pool at 100'C has a pH = 6.15.

TABLE 1.

Pool pH for the TC1 Sequence Both With and Without Cs0H Flow to the Pool.

Time, min pH With pH Without 134 6.15 6.15 139 7.69 5.87 144 7.89 5.74 149 8.02 5.64 153 8.10 5.58 158 8.11 5.56 163 8.12 5.56 168 8.12 5.56 0704160080 070400 PDR NUREG 1150 C PDR hi

Jocelyn Mitchell Page 2 January 15, 1986 As pool 1 inventory increases, the I,igure 1DF generally decreases, if pH 7

changes are low.

This is evident in F It is also possible that 1

if incoming gas has a very low 1 concentration, then the pool I., can be 7

stripped and re-enter the gas phase. This might be possible in home sequences.

At this time I will wait for your or Chuck Nilsen's request for more iodine scrubbing calculations, if needed.

Sincerely yours, d

y P. C. Owczarski Senior Research Engineer Atmospheric & Precipitation Chemistry EARTH SCIENCES DEPARTMENT PCO:dh

.1 Enclosure cc:

K. Lee - BCL C.W. Nilsen - NRC A.K. Postma 0

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Instantaneous Pool DFs for Iodine During the TC1 Sequence.

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