ML20154H987

Non-proprietary,rev 0 to Calculation of TMI-1 ESF Component Leakage Iodine Release

ML20154H987
Person / Time
Site:	Three Mile Island
Issue date:	08/28/1998
From:	Leaver D, Metcalf J POLESTAR APPLIED TECHNOLOGY, INC.
To:
Shared Package
ML20138L274	List: ML20154H971 ML20154H987
References
PSAT-05656A.04, PSAT-05656A.04-R00, PSAT-5656A.4, PSAT-5656A.4-R, NUDOCS 9810150133
Download: ML20154H987 (25)

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.s Non - P re p c 'u. f c-) PSAT 05656A.04 Page 1 of10 Rev. 012'3 4 CALCULATION TITLE PAGE CALCULATION NUMBER: PSAT 05656A.04 CALCULATION TITLE: Calculation of TMI-1 Engineered Safety Feature Component Leakage Iodine Release ORIGINATOR CHECKER IND REVIEWER Print / Sign /Date Print / Sign /Date Print / Sign /Date REVISION: 0 g 6 1 V 2

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REASON FOR REVISION:

Nonconformance Rpt 0 - Initial Issue . N/A 1

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4 9810150133 981006 PDR ADOCK 05000289 P PDR

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PSAT 05656A.04 Page 2 of 10 Rev. 012 3 4 Table of Contents i Section pg Purpose 2 L

Methodology 2 Assumptions 3 References 6 l

Calculation 6 Results - 9 Conclusions 9 Appendix A: ESF Component Leakage Iodine Release with Reduced pH and Liquid -

' Gas Boundary Layer Effect,12 pages

Attachment 1: XL Spreadsheet for TMI-lESF Leakage Fraction Released to Environment,4 pages -

Attachment 2: XL Spreadsheet for TMI-lESF Leakage Fraction Released to Environment (Reduced pH, Boundary Layer),2 pages Attachment 3: XL Spreadsheet Calculation ofIodine Concentration in Bulk Gas Phase with Boundary Layer Effect,44 pages Purpose The purpose of this calculation is to calculate the iodine released to the environment due to engineered safety feature (ESP) component leakage into an ESF component room in.

the auxiliary building, subsequent evolution of the iodine from the leakage pool, and circulation of the building air from the ESF component room to the avironment.

Methodology - .

The overall approach is to apply the Reference [1] Standard Review Plan (SRP) guidance that i.f the calculated flash fraction is less than 10% or if the water is less than 212 F, then an amount ofiodine smaller than 10% of the iodine in the leakage may be used if

~ justified based upon actual sump pH history and veittilation rates. The steps in the r  : calculation are as follows:

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PSAT 05656A.04 Page 3 of 10 Rev. 012 3 4

. Evaluate the elemental iodine concentration in the ESF liquid. This is a function of the core inventory ofiodine, the iodine release from the corj during the DBA LOCA (this iodine is assumed to go into solution in the RCS and reactor building sump liquid which is in turn recirculated through the auxiliary building as ESF liquid), the total ESF liquid mass (i.e., reactor coolant, core flood tanks (CFTs), NaOH tank, and borated water storage tank (BWST)), liquid density, and the ESF liquid pH.

• Evaluate the iodine concentration in the ESF room gas phase. It is assumed that the liquid phase - gas phase partitioning ofiodine is always at equilibrium condition which is a function ofliquid temperature as discussed below under assumptions.

. Using the volumetric flow of gas from the ESF gas space to the environment, calculate iodine release to the environment.

4 Assumptions Assumption 1: The flashing fraction is always less than 10% and the flash release is negligible compared to the calculated release.

Justification: The peak ESF liquid temperature is about 407 K, or 273 F. Using a constant enthalpy method per reference [1],

mh = m,h, + mih; where m is total mass (liquid), h is the initial liquid enthalpy, mg is flashed mass, h, is gas enthalpy, mi is unflashed liquid mass, and hi is unflashed liquid enthalpy. Thus, the flashing fraction, which is the flashed mass divided by the total mass,is f = m,lm = (mh-mihi)lmh, Using initial liquid temperature of 273 F and final temperature of 212 F (corresponding to the saturation temperature at atmospheric pressure which is the final pressure of the flashed mixture), using the steam tables, and setting m = 1 so that the flashing fraction is just mg, we obtain ff =(242-(1-ff)180)/l150

,[f(1150-180) = 242 -180 ff = 0.064 = 6.4%

Since the ESF liquid temperature continuously decreases from 407 K, the i flashing fraction is always < 10%.

The flash release is the iodine released to the gas phase during the flash. It can be estimated as the product of:

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PSAT 05656A.04 Page 4 of 10 Rev. 012 3 4

. The fraction of total iodine in the liquid whish is elemental e The fraction of this elemental iodine which partitions to the gas phase

. The ratio of flashed steam volume to liquid volume

. The fraction ofliquid which flashed.

As is calculated below in the Attachment I spreadsheet, the fraction of total iodine in the liquid which is elemental is roughly lE-7 (due to the high pH). The steam from the flashed liquid has a volume of the order of 1000 times the liquid. The partition coefficient is 'of the order of unity at the peak ESF liquid temperature, and of the order of 0.1 or lower after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The flashing fraction is of the order of 0.1 cc. the beginning of the accident and quickly approaches zero after a few hours. The flashing release can then be approximated as l

(IE-7)(1000)(1)(0.1)= IE-5 at the beginning of the accident, and after a few hours is much lower. As will be seen from the calculation result, the release over 30 days is of the order of IE-3. Thus the flashing release is negligible.

Assumption 2: The iodine partitioning between the liquid and bulk gas is based on equilibrium conditions. That is, a fraction of the 12 in the liquid is assumed to partition instantaneously to the bulk gas phase. This fraction depends only on the temperature of the liquid and does not consider transport of the 12 within the liquid to the liquid - gas interface, nor transport of the 12 across the gas boundary layer between the liquid surface and the bulk gas phase.

Justification: Elemental iodine will transport across the liquid - gas interface (i.e.,

partition) at a rate depending upon its actual vapor pressure in the gas vs.

its saturation vapor pressure. For lower temperatures, the saturation vapor l pressure will be lower and the partitioning will be lower. Similarly, as

. temperature increases, the saturation vapor pressure increases and the partitioning increases. At equilibrium, the actual vapor pressure equals the saturation vapor pressure. Equilibrium conditions have been assumed to simplify the calculation. This assumption is very conservative since it neglects any transient effects and it neglects the resistance to gas transport across the gas boundary layer. This boundary layer effect is considered in the Appendix A calculation.

Assumption 3: The ESF component leakage remains at the reactor building (RB) sump liquid temperature. ,

Justification: ESF liquid is reactor building (RB) sump liquid which is recirculating through three systems in the auxiliary building (makeup, decay heat I

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PSAT 05656A.04 i Page 5 of 10 l Rev. 0' 12 3 4 l removal, and RB spray). ESF component leakage is ESF liquid which l leaks (e.g., pump seal, valve stem) into the auxiliary building room in which the component is located. The ESF component leakage is assumed to remain at the RB sump liquid temperature. In fact there will be heat transfer from the leaked liquid to the auxiliary building room wall surfaces and structures, as well as evaporative heat transfer. This will lower the liquid temperature significantly. For example, referring to reference [2],

items {3.2} and.{4.l }, at 24.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> a mass, M, of roughly (30)(24) +

(30)(50) = 2200 gal, which is about 18,000 lbm or 300 ft , ofleakage has occtured. if this leakage pools in a room of floor area 300 ft2 , the thickness of the poolis 1

th = Volume / Area

= 1 ft The heat transfer from the liquid to the floor surface may be estimated using the liquid temperature at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (163 F) and an assumed floor temperature of 100 F, and a thermal conductivity of water of 0.4 BTU /hr/fteF:

q (BTU /hr) = (0.4)(300)(63/1)

= 7500 BTU /hr Taking c pof water as 1 BTU /lbm/F, we can estimate the time required to decrease the liquid temperature by 5F as T (5F dect) = SMcp/q

= (5)(16000)(1)/7500

= 10 hrs This is about the same rate at which the RB sump liquid cooling is occurring at 24+ hours (see reference [2], item (3.2}). Neglecting this heat transfer is conservative since the amount ofiodine partitioned from the liquid to the gas phase increases with increasing temperature.

Assumption 4: The entire auxiliary building is to be used as a single, well mixed volume for ESF leakage iodine exchange with the environment (volume =

3 1,285,474 ft per reference [2], item {5.4}).

Justification: Use of a single, well-mixed volume is conservative. In fact, the ECCS leakage will be to a room in the auxiliary building basement which has a restricted opening to the remainder of the auxiliary building. Modeling these separate volumes (i.e., two or more volumes in series) would slow the exchange with the environment relative to the single, well-mixed case.

The entire auxiliary building volume has been assumed to exchange with the environment. This also is conservative since this maximizes the

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i PSAT 05656A.04 l Page 6 of 10 Rev. 012 3 4 volumetric flow (and thus the fission product flow) out of the building for a given exchange rate. -

Assumption 5: A volumetric exchange rate of 2 per hour will be used per reference (2),

item (5.5}.

. Justification: This exchange rate is conservative. For example, per reference (5], natural circulation air changes for average residential constmetion under average ,

weather conditions vary over a range of 0.5 to 2 per hour. I References Reference 1: NUREG-0800, NRC Standard Review Plan, Section 15.6.5, Appendix B,

" Radiological Consequences of a Design Basis Loss of Coolant Accident:

Leakage from Engineered Safety Features Components Outside Containment"

. Reference 2: PSAI 05656A.03, " Plant-Specific Design Input for Calculation of TMI-l l ESF Component Leakage Iodine Release", Revision 0 Reference 3: R. Sher and J. Jokiniemi,"NAUAHYGROS 1.0: A Code for Calculating ,

the Behavior of Aerosols in Nuclear Plant Containments Following a Severe Accident," EPRI Report TR-102775, July,1993.

Reference 4: NUREG/CR-5950," Iodine Evolution and pH Control", November 1992 Reference 5: ASHRAE Fundamentals Handbook,1981, Chapter 22, Table 2.

Reference 6: PSAT 05656A.02, " Implementing Procedure for Design Control for Calculation of TMI-l Engineered Safety Feature component Leakage Iodine Release" l

Calculation j

Per reference (6], the calculational approach is to evaluate the iodine release based upon

' actual sump pH history and ventilation rates. This is consistent with the SRP [1]

l guidance, based upon assumption (1) that flashing fraction is less than 10%.

h Condentration in Liquid i This is the first of three calculational sections. This calculational section determines the concentration of elemental iodine in the ESF liquid. -

The total iodine concentration in the ESF liquid is

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PSAT 05656A.04 Page 7 of 10 Rev. 012 3 4

, [Il = (Ic)(frel)/V Esr/130 ,

3 where (Il = total iodine concentration in kgmol/m in the ESF liquid le = total core inventory ofiodine in kg frel = iodine release fraction from core to containment (= 0.5 per reference [1])

V Esr = the volume ofliquid (m3) in which I'is dissolved From reference (2), items (2.l } and {3.l }, I. = 21.4 kg which is 21.4/130 kgmol and total liquid mass m = 3.357E6 lbm (sum of RCS, BWST, NaOH tank, and CFT). From reference [3] the density ofliquid water may be expressed as

1. wour = (4.6137)(0.018016)(1000) 0.26214('+('-N Noting that Vest = m/pwau, we have

[I-] = (21.4)(0.5)/130/(m/ Pwou,) kgmol/m3 Equation 1 Now using equation [12] from reference (4), the elemental iodine concentration in the liquid may be calculated Equations 1 and la are used to obtain [Il and [12]aq as a function of temperature (see Attachment I spreadsheet, discussed further below). One exception is for 0 to 29.1 minutes during which time recirculation has not yet been initiated (per reference [2), item

{4.3}) and (Il and (12]aq are zero, h Concentration in Bulk Gas -

Per assumption (2), the iodine partitioning between the liquid and bulk gas is based on equilibrium conditions.

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l b Release from Gas Space The 12 release from the auxiliary building to the environment is equal to the product of the volumetric gas flow from the auxiliary building to the environment in m per hour and (12]g. Per assumption (4) the entire auxiliary building'is to be considered in the ESF leakage iodine release problem (volume V = 1,285,474 ft ). Per assumption (5) volumetric gas flow to the environment is based on an exchange rate, 9 / V , of 2 volumes L

. per hour where 9 is volumetric flow m 3per hour. (Attachment I also includes sensitivity calculations for exchange rates of 1,3, and 5 per hour.)

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l l Results The results of this calculation are presented in Tables 1 and 2. (Tables 1 and 2 are taken q from the Attachment I spreadsheet. Table 1 is taken from column 12 of page 2 of the i spreadsheet, and Table 2 is taken from the release fractions over Chi /Q intervals [ lower left hand subtable on page 2 of the spreadsheet). There are 4 pages in Attachment 1, one page for each exchange rate with exchange rate 2 per hour being the base case reported in Tables 1 and 2.)

The results are in units of fraction of total iodine leaking into the ESF component room (s)

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(i.e., fraction of the total ~ dissolved iodine in the 30 gal per hour). As is evident from Table 1, in the first 29.1 minutes (1746 seconds) the release is zero since recirculation has not yet started. Early in the accident the release is several percent of the total iodine in the leakage. The fraction decreases with time and is less than 1% percent after a day. This decrease is due mainly' to decreasing temperature as the ESF liquid is cooled (and thus the amount ofiodine partitioning from the liquid decreases per equations 2 and 3).

' For input to the dose calculation, the Fraci quantities in Table 1 (from equation 5) have been time-weighted to produce a fractional release of total incoming iodine for time intervals corresponding to the chi /Q intervals. This is presented in Table 2.

Conclusions The conclusion from this calculation is that the iodine release from ESF leakage for TMI-

~ l is under 3% of the total incoming iodine in the leakage, for exchange rate of 2 per hour, for all of the Chi /Q intervals. .

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' Page 10 of 10 Rev. 012 3 4 Table 1 Fraction ofIncoming Iodine Released Frac, Time (Fraction of Interval Incoming 1

(sec) lodine) 75 to 720 N/A 720 to 1746 N/A 1746 to 3300 4.69E-02 3300 to 7200 3.52E-02 7200 to 28800 2.15E-02 28800 to 86400 1.39E-02 86400 to 88200 2.04E-04 88200 .to 172800 9.54E-03 172800 to 345600 8.21E-03 345600 to 500000 7.38E-03 500000 to 2.59E+06 5.46E-03 Table 2 Fraction ofIncoming Iodine Released During Chi /Q Periods Time Period Fraction of incoming lodine '

O to 2 hr 2.92E-02 2 to 8 hr 2.15E-02 ,

8 to 24 hr 1.39E-02 24 hr to 24.5 hr 2.04E-04 1 to 4 days 8.65E-03 4 to 30 days 5.59E-03 l

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PSAT 05656A.04 Page Al of A12 Rev.012 3 4 i- APPENDIX A l

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L - APPENDIX TITLE: ESF Component Leakage lodine Release with Reduced pH

!. and Liquid - Gas Boundary Layer Effect CALCULATION TITLE:

Calculation of TMI-l Engineered Safety Feature j Component Leakage Iodine Release Table of Contents L Section Palle l

t Purpose A1 Methodology A1 Assumptions A2 References A4 Calculation A4 Results All I

Conclusions A12 L

i Purpose The purpose of this appendix is to calculate the effect of reduced pH and the effect of the liquid - gas boundary layer on the main calculation result for ESF component leakage lodine release to the environment. This' calculation is being performed to assess the sensitivity of the main calculation result to pH. Reduced pH will increase the iodine L release. For simplicity, the boundary layer effect was not considered in the main calculation. It is, however, considered here since the effect is significant and since methods exist to address the effect.

Methodology

t. . The overall approach is to apply the Reference [1] Standard Review Plan (SRP) guidance l similar to the main calculation. The differences are use of pH 7.5 and 7 (vs. pH 8 in the i main calculation) and development and application of a model for the mass transfer of iodine across the boundary layer between the liquid surface and the bulk gas space in the auxiliary building. The steps in the calculation are as follows:

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• As in the main calculation, evaluate the elemental iodine concentration in the ESF liquid.

. Evaluate the gaseous iodine concentration at the liquid edge' of the gas boundary layer. This is accomplished in the same manner as the main calculation evaluation of the iodine concentration in the ESF room gas phase except here this concentration becomes a boundary condition for the transport ofiodine across the gas boundary layer. As in the main calculation, it is assumed that the liquid phase - gas phase partitioning ofiodine is always at equilibrium condition which is a function ofliquid l temperature.

Evaluate the mass transport ofiodine across the gas boundary layer . The iodine l_ concentration gradient and the mass transfer coefficient must be considered here. This L will allow determining the bulk gas iodine concentration, which is a function of the  !

l iodine mass flux across the gas boundary layer and a mass balance with the iodine L

removal due io the volumetric exchange of the bulk gas space with the environment.

e Using the volumetric flow of gas from the ESF gas space to the environment,

! calculate iodine release to the environment. )

i Assumptions j l Assumption 1: The flashing fraction is always less than 10% and the flash release is l l negligible compared to the calculated release.

Justification: Same as in main calculation.

Assumption 2: The iodine partitioning between the liquid and the liquid edge of the gas boundary layer is based on equilibrium conditions.

Justification: Same principle as in main calculation, excep; it is applied only to the gas concentration at the liquid edge of the gas boundary layer.

i Assumption 3: The ESF component leakage remains at the reactor building (RB) sump L liquid temperature.

Justification: Same as in main calculation. This assumption is even more conservative-here than in the main calculation since as evident from assumption (6) below, the area of the liquid layer has been maximized which will increase heat transfer from the liquid to room surfaces and thus increase the rate of liquid temperature decrease.

Assumption 4: The entire auxiliary building is to be used as a single, well-mixed volume for ESF leakage iodine exchange with the environment (volume =

1,285,474 ff per reference [2), item (5.4}).

Justification: Same as in main calculation.

l Assumption 5:The sump liquid (and thus the ESF liquid) pH is 7.5 and 7.

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Rev.012 3 4 Justification: Two cases for sump pH were calculated to determine the sensitivity of the

-. main calculation (pH 8) result to pH. Per refererice (7], one of the cases was pH 7.

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i-l Assumption 9: A volumetric exchange rate of 2 per hour will be used.

Justification: Same as in main calculation.

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References .

Reference 1: NUREG-0800, NRC Standard Review Plan, Section 15.6.5, Appendix B,

" Radiological Consequences of a Design Basis Loss of Coolant Accident:

i Leakage from Engineered Safety Features Components Outside l

i Containment" Reference 2: PSAT 05656A.03, " Plant-Specific Design Input for Calculation of TMI-l ESF Component Leakage Iodine Release", Revision 0 l

l Reference 3: R. Sher and J. Jokiniemi,"NAUAHYGROS 1.0: A Code for Calculating the Behavior of Aerosols in Nuclear Plant Containments Following a

. Severe Accident," EPRI Report TR-102775, July,1993.

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Reference 7: PSAT 05656A.02, " Implementing Procedure for Design Control for Calculation of TMI-1 Engineered Safety Feature component Leakage Iodine Release" Calculation j l

As in the main calculation and per reference [7], the calculational approach is to evaluate i the iodine release based upon actual sump pH history and ventilation rates, with the l

additional step of consideration of the effect of the gas boundary layer at the pool surface. '

This is consistent with the SRP [1] guidance, based upon assumption (1) that flashing

. fraction is less than 10%.

b Concentration in Liquid This is the first of four calculational sections. This calculational section determines the concentration of elemental iodine in the ESF liquid.

1 The total iodine concentration in the ESF liquid is j

[I'] = (Ic)(frel)N Esr/130 t where -[I'] a total iodine concentration in kgmol/m3 in the ESF liquid i l le = total core inventory ofiodine in kg frel = iodine release fraction from core to containment (= 0.5 per reference [1])

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PSAT 05656A.04 Page AS of A12 Rev.012 3 4 Vest = the volume ofliquid (m 3) in which I is dissolved From reference [2], items {2.l} and {3.1),le = 21.4 kg which is 21.4/130 kgmol and total liquid mass m = 3.357E6 lbm (sum of RCS, BWST, NaOH tank, and CFT). From reference (3) the density ofliquid water may be expressed as (4.6137)(0.018016)(1000)

O.26214(1+(1-T/647.29)o23072 where T is degrees Kelvin. Noting that Vgsg = m/po,,, we have

[I-] = (21.4)(0.5)/130/(m /po,,,) kgmol/m 3 Equation 1 12 Concentration at Liquid Edge of Gas Boundary Layer See Proprietary Version i

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, 'l PSAT 03656A.04 Page A6 of A12 Rev.012 3 4 Gas Transport ofIodine Across Boundary Layer The problem ofiodine gas transport across the gas boundary layer at the liquid - gas interface is illustrated in Figure 1. [12]aq and [I 2]Si are known from equations I through 3.. The object of this gas transport calculation is t.o solve for [I2]gb.

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Figure 1 Illustration of Boundary Layer i

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l PSAT 05656A.04 I Page A7 of A12 Rev.012 3 4 The problem of mass transfer of the iodine gas across the gas Soundary layer at the liquid

-gas interface is treated by defining a mass transfer coefficient in a manner similar to that used for defining a heat transfer coefficient l

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The solutions to equation 9 for steady state [I 2]gh and to equation 13 for transient [I2]gb are provided in the Attachment 3 spreadsheets. The attachment consists of 9 spreadsheets, one for each of the 9 time intervals after 29.1 mint.tes (which in turn correspond to a given ESF leakage pool temperature - see Attachment 2 for time intervals and corresponding temperatures). For the first time interval with non zero iodine l concentration in the ESF leakage (i.e., the third time interval) in' Attachment 3, the transient calculation has been carried out for 3600 seconds (pages 1 - 9 of Attachment 3).

- For the remaining 8 time intervals (intervalu 4 to 11) in Attachment 3, the transient calculation is carried out only to.320 seconds to confirm that the transient behavior is l similar to the first time interval. Except for the third Attachment 3 time interval, a time i- - interval (i.e., spreadsheet) consists of 4 pages: page 1 is the steady state and transient (to L 320 seconds) result for [I2]gb; page 2 includes case-specific and non-case specific inputs to the mass transfer calculation; page 3 is the calculation of the Sherwood Number; and

! page 4 is'a calculation of[I2181. For the third Attachment 3 time interval, the spreadsheet

- is 12 pages: 9 pages for the transient [I 2]gh calculation (to 3600 seconds), and I page each for the inputs, Sherwood Number, and [I2]gi. Thus Attachment 3 is 44 pages.

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PSAT 05656A.04 Page Al1 of A12 Rev.012 3 4 It is noted that the boundary layer model in the spreadsheets is configured for a 2 volume bulk gas region, although the problem addressed here assumes a single, well-mixed volume per assumption (4).

Nine values of the steady state, turbulent boundary layer decontamination factor (DF) corresponding to the 9 time intervals (after 29.1 minutes) for Attachment 3 are recorded in column 11 of Attachment 2. Boundary layer DF is defined as the elemental iodine concentration in the bulk gas without the boundary layer effect divided by the elemental iodine concentration with this effect The turbulent value has been used since this gives a higher iodine diffusion. [1 2]gb is calculated in column 12 by dividing (I218: by boundary layer DF.

12 Release from Gas Space The 12 release from the auxiliary building to the environment is equal to the product of the volumetric gas flow from the auxiliary building to the environment in m and [I 2]gb.

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l Results l l

The results of this calculation are presented in column 14 of the Attachment 2 spreads,heet. The results are in units of fraction of total iodine leaking into the ESF l component room (s) (i.e., fraction of the total dissolved iodine in the 30 gal per hour). In l addition, the Fraci quantities from equation 15 have been time-weighted to produce a l fractional release of total incoming iodine for time intervals corresponding to the chi /Q intervals. This is calculated and presented in the lower letT of the Attachment 2 spreadsheet.

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PSAT 05656A.04 Page A12 of A12 Rev.012 3 4 As is evident from the time weighted Fraci quantities, for pH 7.5 the release is under 2%  !

for 0 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, decreasing to a few tenths of a percent at 30 da' ys. The decrease with time is due mainly to decreasing temperature as the ESF liquid is cooled (and thus the amount ofiodine partitioning from the liquid decreases per equations 2 and 3). For pH 7, 1 the release is an order of magnitude higher. It should be noted, however, that the conservatisms discussed below would lower the release well below this result. l The steady state boundary layer effect has been calculated at the top of Attachment 3 and .

expressed in terms of a decontamination factor (DF). This DF is the bulk gas iodine i concentration without the boundary layer effect divided by the concentration with the  !

boundary layer effect (i.e., [I 2]g/[I2]Sb). As is evident from Attachment 3, the turbulent l boundary layer results in a DF of about 20. The laminar boundary layer results in a DF larger by about a factor of 2.

The transient boundary layer effect may be understood by examining the first 9 pages of Attachment 3. It is seen that after I hour, [I2]gb is about 90% of the steady state value.

This suggests that neglecting transient behavior over the first hour or two is conservative. 1 Further, the approach to steady state is fast enough relative to later time intervals (which are of the order of many hours to days) that neglecting transient effects will have negligible effect on the release. It may further be observed that in the approximately 5 second duration of droplet fall for the jetted leakage discussed in assumption (8), the transient gas concentration will be negligible.

1 It is noted that the results reported here are quite conservative, particularly with respect to two effects: (1) the area of the ESF leakage pool was overestimated by assuming that a liquid layer is maintained on all walls and equipment surfaces in the area in which the leakage occurs; this significantly increases the mass transport across the boundary layer; and (2) the ESF leakage temperature was estimated by assuming no heat transfer from the leaked liquid to the structures and surfaces in the area in which the leakage occurs. These effects were treated in this manner for simplicity, and could be reevaluated if necessary to provide a more realistic estimate of the boundary layer.

Conclusions The conclusions from this calculation are as follows:

e For the case of pH 7.5 and considering the boundary layer effect, the iodine release from ESF leakage for TMI-1 varies over the range of between 0.5% and 1.5% early, decreasing to about 0.3% at 30 days. For pH 7, the iodine release varies over the range of between 7% and 14% early, decreasing to about 3% at 30 days e The effect of the boundary layer on iodine release, as modeled here, is about a DF of 20.

. Page 2 of 4 PSAT 05656A.04 Rev.0 * 'i Attachment 1 i Attachment 1 XL Spreadsheet for TMI-1 ESF Leakage Fraction Released to Environment ,

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Rev.O Attachment 2 Attachment 2 XL Spreadsheet for TM-1 ESF Leakage Fraction Released to Environment ,

Nary Layer)

See Proprietary Version B

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Page 1 of 44 PSAT 06565A04 Rev.0 *b Attachment 3 s

A2tachment 3 XL Spreadsheet Calculation of lodine Concentration in Bulk Gas with BL Effect, AB 305 Area (Third time interval)

Solvelon Usina Laminor Mass Transfer Cosmcient Solution Usine Tur'w h= Transfer C- - - 4 -

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[12]gb= 9.1E-12 kgmolom3 Steady state solution [t2]gb= 4.6E-12 kgmolkn3 Senady state solution -

Boundary layer DF= 20.21609 Boundary layer DF= 39.64093 l

See Proprietary Version  ;

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