ML032671359

Calculation DRE01-0040, Site Boundary and Control Room Doses Following a Loss of Coolant Accident Using Alternative Source Terms, Revision 1

ML032671359
Person / Time
Site:	Dresden, Quad Cities
Issue date:	08/22/2002
From:	Baron J, Ferguson K Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
DRE01-0040, Rev. 1
Download: ML032671359 (82)

Text

ATTACHMENT 6 Calculation DREOI-0040, "Site Boundary and Control Room Doses Following a Loss of Coolant Accident Using Alternative Source Terms,"

Revision 0, dated August 22, 2002

CC-AA-309 - ATTACHMENT I - Design Analysis Approval Page 1 of 2 DESIGN ANALYSIS NO.:

DRE01 - 0040 Major REV Number: 000 Minor Rev Number: 000 PAGE NO. 1

[ I BRAIDWOOD STATION DESCRIPTION

[ l BYRON STATION DESCRITO N01,RolR02

[ 1 CLINTON STATION E

)

[

LASALLE CO.STATION DISCIPLINE CODE:

N QUAD CITIES STATION (CO 1)

Unit:[ 10 [ 11

[X]2 [X]3 SYSTEMCODE: (COll)

NA TITLE:

Site Boundary and Control Room Doses following a Loss of Coolant Accident using Alternative Source Terms X ] Safety Related 1

Augmented Quality

[ I Non-Safety Related ATTRIBUTES (C016)

TYPE VALUE TYPE VALUE Elevation Software COMPONENT EPN:

DOCUMENT NUMBERS: (C012 Panel) (Design EPN TYPE Analyses References)

Type/Sub Document Number Input (YIN)

ReporttEng GE-NE-A22-00103-64-01, RO Y

Letter/Eng EXELON TODI E2002-9994, RI Y

CalclEng S&W 08645.7022-UR(B)-O01, Ro Y

CalclEng DRE02-0033, Ro Y

REMARKS:

Page 1 of 58 (Printed: 08/22102 8:40 AM)

E-Form CC-AA-309-1 vA.1 for use with CC-AA-309 Revision 1 and above.

CC-AA-309 - ATTACHMENT 1 - Design Analysis Approval

~~~~~W_

~~~Page 2 of 2 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO. 2 Revision Summary (including ECs Incorporated):

Original Issue Electronic Calculation Data Flies:

(Program Name, Version, File Name extension/size/date/hour/min)

Design Impact review completed?

[ Yes

[X I N/A, Per EC#: 356084 (If yes, attach impact review sheet)

Prepared by:

K. P. Ferguson J

Print Date Reviewed by:

J. S. Baron 8/22102 Print sgn Date Method of Review:

[x 3 Detailed t ] Alternate

[ ] Test This Design Analysis supersedes:_

In Its entirety.

Supplemental Review Required? ' I Yes

.- XJ No Additional Review :1 J

Special Review Te m-'.

Additional Reviewer or Special ReviewTeaM Leader.: -

Print,.

Sign.

Date-Special ReviewTeam:.(NA for-Adi'oa Revie Reviewers: 1) i 2)J_

_2)

Print2 ign..

..Date Print Sigr

. Dati.2 Print

Sign.

Wo.Dat Print SIPnDa6 Supplemental Rei ew1Results

'1 Approved by:

Sreela R. Ferguson Q

8122102 Print Sgn Date External Desion Analysis Review (Attachment 3 Attached)

Reviewed by:

I J

Print Sign Date Approved by:

Print Sign Date Do anyASSUMPTIONS/ENGINEERING JUDGEMENTS require ater vefication?

[ ] Yes [X ] No Tracked By, AT#, EC# etc.)_________________

Page 2 of 58 (Printed: 08/2202 8:40 AM)

E-Form CC-AA-309-l v1.1 for use with CC-AA-309 Revision I and above.

NES-G-1 4.01 Effective Date:

04/14100 CALCULATION TABLE OF CONTENTS CALCULATION NO. DREOI-0040 REV. NO. 0 PAGE NO. 3 SECTION:

PAGE NO.

SUB-PAGE NO.

TITLE PAGE REVISION

SUMMARY

TABLE OF CONTENTS 1.0 PURPOSE / OBJECTIVE

2.0 INTRODUCTION

AND ACCEPTANCE CRITERIA 3.0 METHODOLOGY 4.0 ASSUMPTIONS / ENGINEERING JUDGEMENTS 5.0 DESIGN INPUTS

6.0 REFERENCES

7.0 CALCULATION 8.0

SUMMARY

AND CONCLUSIONS APPENDIX A ATTACHMENTS A. EXELON TODI ER2002-9994, Rev 1 B. CDROM OF COMPUTER OUTPUT

• 1 2

3 4

4 5

21 21 27 29 42 46 23 pages 1 page i

i E-FORM I

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.4 1.0 PURPOSE/ OBJECTIVE The purpose of this analysis is to determine the dose at the Exclusion Area Boundary (EAB), Low Population Zone (LPZ) and Control Room (CR) following a Loss of Coolant Accident (LOCA) at the Dresden (DRE) Station. The calculated dose is based on

'Alternative Source Terms", cloud submersion and inhalation pathways. Part 1 of the calculation is based on current design basis parameters as provided by EXELON via Ref.4.

Part 2 of the calculation determines doses based on proposed changes to selected design basis parameters.

EXELON has identified three release pathways: (1) primary containment leakage into the Reactor Building and exhausted via the SBGT system; (2) primary containment leakage directly to the environment through the MS Isolation Valves; and (3) ESF leakage from equipment and systems that leak Into the Reactor Building and exhaust via the SBGT system.

Additionally, per EXELON request, Appendix A of this analysis documents a sensitivity study of Main Steam line leakage versus the 30 day control room operator TEDE dose following a LOCA. The results of this study is utilized by EXELON to facilitate the selection of the proposed design changes relative to MSIV leakage.

2.0 INTRODUCTION

AND ACCEPTANCE CRITERIA Introduction Dresden Power Station (DPS) is investigating the possibility of increasing allowable MSIV leakage. In addition, operational relief is being investigated in the areas of increasing allowable containment leakage, ESF leakage and control room Inleakage, and reducing the required charcoal filter Iodine removal efficiency for both the Standby Gas Treatment System (SGTS) and the Control Room Emergency Ventilation system.

As a holder of an operating license issued prior to January 10, 1997, and in accordance with 10CFR50.67 (Reference 1), to support the above change in operation mode, DPS Is considering the voluntary replacement of the TID 14844 (Reference 2) accident source term currently used to analyze the dose consequences at the site boundary and in the control room due to airborne releases following a Loss of Coolant Accident (LOCA), with the Alternative Source Term (AST).

The source terms l methodology used in the assessment summarized in this calculation reflect the guidance provided in Regulatory Guide 1.183 (Reference 3).

The plant specific input parameters utilized to perform this analysis were provided to S&W by EXELON via a QA parameter list. (Reference 4) l E-FORM l

NES-G-1 4.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.5 This evaluation has been divided into two parts. Part 1 entails the assessment of the base case which is intended to reflect current design basis (identified by EXELON via Reference 4 as Case 1). Upon review of the dose consequences of the base case, EXELON identified several sensitivity studies from which one scenario was selected as the proposed new design basis, and is included in this calculation as the Part 2 analysis (identified by EXELON via Reference 4 as Case 2).

Acceptance Criteria The acceptance criteria for the EAB and LPZ Dose is based on 10 CFR Part 50 § 50.67, and Section 4.4 Table 6 of Regulatory Guide 1.183:

(I)

An individual located at any point on the boundary of the exclusion area for any 2-hour period following the onset of the postulated fission product release, should not receive a radiation dose in excess of the total effective dose equivalent (TEDE) value of 25 REM noted in Reference 3, Table 6.

(ii)

An individual located at any point on the outer boundary of the low population zone, who is exposed to the radioactive cloud resulting from the postulated fission product release (during the entire period of its passage), should not receive a radiation dose in excess of the TEDE value of 25 REM noted in Reference 3, Table 6.

The acceptance criteria for the Control Room Dose is based on1O CFR Part 50 § 50.67:

Adequate radiation protection is provided to permit occupancy of the control room under accident conditions without personnel receiving radiation exposures in excess of 0.05 Sv (5 rem) total effective dose equivalent (TEDE) for the duration of the accident.

3.01METHODOLOGY Radiation Source terms The inventory of fission products in the DPS reactor core is based on maximum full-power operation of the core at a power level equal to the Extended Power Uprate (EPU) thermal power level of 2957 MWth plus a 2% instrument error per Regulatory Guide E-FORM l

NES-G-14.02 Effective Date:

04/14DOO DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.6 1.49 (Reference 5); i.e. 3016 MWth, and a 24 month fuel cycle. The inventory used for the LOCA analysis represents a average core bumup of 1600 EFPD.

The DPS equilibrium core inventory per Megawatt was calculated by GE using computer code ORIGEN2 and is documented In GE task Report No. GE-NE-A22-00103-64-01. (Reference 6)

The standard library I input to Computer code RADTRAD is limited to a pre-selected group of 60 isotopes which were determined by the code developer as significant in dose consequence. The equilibrium core inventory of these isotopes is presented in the Inputs Section as Datum#6.

Table 1 in Regulatory Guide 1.183, specifies the fraction of Fission Product Inventory released Into containment following a DBA LOCA in a BWR. Both the Gap and Early In-Vessel release fractions to be applied to the equilibrium core inventory are provided.

The release fractions listed are determined to be acceptable for use with currently approved LWR fuel with a peak burnup of 62,000 MWD/MT. DPS fuel meets the criteria identified in RG 1.183. The release fractions recommended by RG 1.183 are reported below:

Gap Group Noble gas Halogens Alkali Metals Tellurium Group Ba, Sr Noble Metals Cerium Group Lanthanides Early In-Vessel Release Phase 0.05 0.05 0.05 Release Phase 0.95 0.25 0.20 0.05 0.02 0.0025 0.0005 0.0002 Table 5 of Regulatory Guide 1.183 lists the elements in each radionuclide group that should be considered in DBA LOCA analysis. This list is provided below Group IsotoDes Noble gases:

Halogens:

Alkali Metals:

Tellurium Grp:

Ba, Sr:

Noble Metals:

Cerium Grp:

Lanthanides:

Xe, Kr l,Br Cs Rb Te, Sb, Se Ba, Sr Ru, Rh, Pd, Mo, Tc, Co Ce, Pu, Np La, Zr, Nd, Eu, Nb, Pm, Pr, Sm, Y, Cm, Am E-FORM I

NES-G-1 4.02 Effective Date:

04100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.7 Table 4 of the Regulatory Guide 1.183 provides the onset and duration of each sequential phase for the DBA LOCA at a BWR. Per RG 1.183, the early in-vessel phase immediately follows the gap release phase. The associated information is repeated below.

Phase Onset Duration Gap Release 2 mins 0.5 hrs Early-In-Vessel 0.5 hrs 1.5 hrs Dose Calculation Methodoloav The 2 hr EAB, and 30-day LPZ and Control Room Total Effective Dose Equivalent (TEDE) is calculated using industry computer code RADTRAD (Reference 7). The TEDE is the sum of the Committed Effective Dose Equivalent (CEDE) and the Deep Dose Equivalent (DDE).

RADTRAD calculates the submersion dose (DDE) and the inhalation dose (CEDE) at offsite locations and the control room. All doses are estimated using Federal Guidance Reports 11 and 12 (References 8 and 9) dose conversion factors (DCFs) for the following organs and pseudo-organs:

Gonads Breast Lungs Red bone marrow Bone surface Thyroid Skin Effective dose equivalent - Remainder The RADTRAD activity transport model first calculates the activity at the offsite locations and in the control room air region. The decay and daughter build-up during the activity transport among compartments and the various cleanup mechanisms are included in the activity calculation.

No modifications are performed external to the code. The doses are based on the integrated total activity, occupancy factors (for control room only), and ICRP-30 dose conversion factor methodology. All doses herein are based on the RADTRAD option for Federal Guidance Reports No. 11 and 12 Inhalation and external exposure dose conversion factors, respectively. Note that per RG-1.183, RADTRAD assumes that the Effective Dose Equivalent (EDE) is equivalent to the DDE.

E-FORM I

NES-G-1 4.02 Effective Date:

04)14100 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.8 Offsite Dose The dose to a hypothetical individual is calculated using plant specific X/Qs and the amount of each nuclide released to the environment during each exposure period. The air immersion dose from each nuclide, n, at a offsite location is calculated as:

2whr

= An DCF where :

net5M air submersion dose due to nuclide n at a location (Sv)

DCFen cAn ion FGR 12 air submersion dose conversion factor for nuclide n (

1 )

Bq s atmospheric dispersion coefficient from release point to location (

)

released activity of nuclide n (Bq)

The inhalation dose from each nuclide, n, is calculated as:

0 locationWOW here =

• BR

• DCF n where BR DCFin inhalation dose commitment due to nuclide L7 at a. location (Sv)

Breathing rate (r77l,)

FGR 11 inhalation dose conversion factor for nuclide n ( S- )

Bq The dose to an individual in the control room is calculated based on the time-integrated concentration in the control room. The air submersion dose is:

=f C(t) dt C(

GF I

E-FORM I

NES-G-1 4.02 Effective Date:

04/14DO0 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.9 where Bq C(t) is the instantaneous concentration of radionuclide n in the control room. (

GF the Murphy-Campe geometric factor relating dose from an infinite cloud to the dose from a cloud of volume V (ft3) as 1173 G= VO.338 The inhalation dose in the control room is

< =IJC,(t)

• BR

• OF *DCF,;"

dt where OF occupancy factor The following derived doses are also calculated:

Whole body (effective air submersion dose)

Thyroid (thyroid chronic inhalation dose)

TEDE (effective air submersion dose + effective committed effective dose equivalent)

Activity Transport Model RG 1.183 identifies the large break LOCA as the design basis case of the spectrum of break sizes for evaluating performance of release mitigation systems / containment and facility siting relative to radiological consequences.

Computer program RADTRAD is used to calculate the airborne dose to the operator in the control room and to a member of the Public located at the EAB/LPZ following a LOCA.

RADTRAD utilizes an analytical computational process, that addresses radionuclide progeny, time dependent releases, transport rates between regions and deposition of radionuclide concentrations In sumps, walls and filters. The Dresden LOCA activity transport and dose model for RADTRAD is shown on Figure 1.

RADTAD has not been validated or verified in accordance with S&Ws 10 CFR 50 Appendix B QA program, therefore the transport model for each release path (i.e., MSIV release pathway, containment release pathway, and ESF Release pathway) developed for RADTRAD is checked against S&W's QA Cat I transport and dose consequence program PERC2.

Comparing both programs calculated total 1-131 (principal dose I

E-FORM

NES-G-14.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.10 contributor) environmental activity release and calculated control room operator thyroid dose from each pathway provides sufficient verification of RADTRAD results. The LOCA activity transport model for PERC2 is shown on Figure 2.

The worst 2-hour period dose at the EAB, the dose at the LPZ for the duration of the release, and the 30 day control room dose is calculated based on the postulated airborne radioactivity releases following a LOCA. The calculated dose represents the post accident dose to the public and to the control room operator due to inhalation and submersion.

The LOCA analysis is based on the guidance set forth in Regulatory Guide 1.183, and DPS design parameters as provided via Reference 4. Note that selected portions of the analysis utilizes a fifth unit concept, i.e.; the most conservative value applicable to Dresden and Quad Cities Station is used.

As indicated previously, this assessment has been divided into two parts. Part 1 entails the assessment of the base case, which is intended to reflect current design basis (identified by EXELON via Reference 4 as Case 1). Upon review of the dose consequences of the base case, EXELON requested several sensitivity studies be performed including a focussed sensitivity study of MSL leakage vs 30 day control room TEDE dose based on the limiting station and a proposed control room unfiltered inleakage of 600 scfm (see Appendix A).

Based on a review of the results of the referenced studies, and the MSL leakage vs control room dose study documented in Appendix A, EXELON has selected the proposed new design basis, which is included in this calculation as the Part 2 analysis (identified by EXELON via Reference 4 as Case 2).

Base Case (PART 1)

As noted in Reference 4, DPS has identified three (3) leakage pathways following a LOCA:

Containment airborne activity that leaks directly to the environment, untreated, via the Main Steam Isolation Valves (MSIVs)

Containment airborne activity which leaks into the reactor building (RB),

mixes with the RB atmosphere, and Is released to the environment, after filtration via the standby gas treatment system (SBGTS); and ESF leakage, or suppression pool water leaking from lines and equipment circulating suppression pool water in the Reactor Building, made airborne, and discharged via the RB SBGTS Per Reference 4, current plant design does not allow bypass of the SBGTS.

I E-FORM I

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.11 Containment Airborne Activity In accordance with Reference 3, the fission products released from the fuel are assumed to mix instantaneously and homogeneously throughout the free air volume of the drywell air space as it is released from the core. No suppression pool scrubbing is assumed since the bulk of the activity is released well after the initial mass and energy release. Per RG 1.183, two fuel release phases are considered for the DBA LOCA analyses: a) the gap release, which begins 120 secs after the LOCA and continues for 30 minutes and b) the early In-Vessel release phase which begins 30 minutes after the onset of the gap and continues for 1.5 hrs. The core inventory release fractions, by radionuclide group, for the gap and early in-vessel phase are based on guidance provided in Regulatory Guide 1.183, and are listed in Section 3.

In accordance with Reference 3, the chemical form of the radioidine released from the fuel is 95% cesium iodide (Csl), 4.85% elemental iodine, and 0.15% organic iodine.

With the exception of noble gases, elemental and organic iodine, fission products are assumed to be in particulate form.

Activity made airborne in the primary containment is depleted by natural deposition within the containment. Elemental iodine is reduced by a plateout removal coefficient (3.28 hr') using the methodology outlined in SRP 6.5.2, Rev.2 (Reference 10).

Parameters utilized to develop this coefficient include the surface area of the drywell (32,250 sq ft) and Containment free volume (1.58E5 cu.ft). The maximum DF for elemental iodine is based on SRP 6.5.2 and is limited to a DF of 200. For DPS, this DF value is reached at 3.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Credit for elemental iodine removal in the drywell is therefore stopped at T= 3.1 hrs after the LOCA.

In accordance with Reference 3,

particulate aerosols are removed by deposition/plateout using the equations for the "Powers Model" In NUREGICR-6189 (Reference 15) with the 10% uncertainty percentile which results in the lowest activity removal efficiency provided by the model.

Because the "Powers Moder' applies a separate set of lambdas for the gap and early-in-vessel release, two RADTRAD runs are required, one for the gap phase and one for the early-in-vessel core release phase.

The output dose results from the gap and early-in-vessel core release phases are added to obtain the total dose.

Per Reference 16, long term suppression pool pH (taking Into consideration acid production due to radiolysis and cable degradation) is estimated to be greater than 7.

Per Reference 4, credit is taken for the sodium pentaborate in the Standby Liquid Control System, which is assumed to be manually initiated via the EOPs such that the entire inventory of sodium pentaborate is delivered and mixed in the suppression pool I

E-FORM l

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.12 within 24 hrs of the LOCA. Consequently, per Reference 3, iodine re-evolution is not addressed.

Containment Leakaae via MSIVs A portion of the containment leakage (per Reference 4, the total leakage is 0.016 volume fractions per day) is released via the MSIVs. Per Reference 4, during accident conditions, the 4 MSS lines leak at a combined rate of 79.6 scfh @ 48 psig (0.00283 containment volume fractions per day) or at 46 scfh at a test pressure of 25 psig. This leakage is assumed to be valid for the duration of the event.

Consistent with the guidance of RG 1.183, activity leakage via this pathway Is assumed to experience deposition, plateout and holdup as it traverses the steam lines before being released to the environment, i.e.; the activity traversing the approximately 93 ft (min pipe length value) of MS piping is depleted and decayed before it released with ground level dispersion. The deposition model used in the analysis utilizes aerosol and elemental iodine removal lamdas developed using S&W proprietary methodology based on information provided in References 11 and 15. These lambdas are documented In Reference 13 which uses the fifth Unit concept, i.e., the most conservative value for each input value applicable to the main steam lines at Dresden and Quad Cities Station is utilized.

The RADTRAD activity transport model is shown in Figure 1. Consistent with current Technical Specifications all Main Steam activity leakage is conservatively, assumed to leak from one MSL. The outboard MS valve is assumed to fail open minimizing non-gaseous activity deposition. As shown in Figure 1 the MSL is broken into 5 regions, 4 horizontal sections and 1 vertical section. Multiple regions were used to more closely represent the plug flow.

Deposition is achieved using time dependent removal coefficients. The 5 region MS line leakage model and associated time dependent aerosoVelemental iodine deposition rates utilized in this analysis are taken directly from Reference 13 and are based on S&W proprietary methodology. Natural deposition of organic iodine in MSLs is not credited herein. The PERC2 model used to validate and verify RADTRAD results uses an overall DF developed externally in Reference 13 to the program to account for deposition in the MSL(s). Although the PERC2 activity transport model has a single MSL region, the overall DF used in the PERC2 analyses was developed using the 5 region MSL activity transport model from Reference 13.

rime for initiation of MSL releases to the environment was determined using a criteria of 40 minutes (i.e.; time at which the CR is In full emergency ventilation operation ) or 1/8 the time determined using a plug flow model for retention to address convective flow -

whichever time was smaller. For all cases considered, 40 minutes was the limiting time for initiation of MSIV releases. The average transit time (base case) for the worst line in plug flow is V/F = 160 ft31/ 0.311 cfm /60 min/hr or 8.6 hrs. Since 40 min < (8.6 hrs 18),

I E-FORM 7

NES-G-1 4.02 Effective Date:

04/4100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO.13 the model assumed that the leading edge would begin environmental release at 40 min after the LOCA.

Containment leakage via the SBGTS The portion of the containment leakage not released via the MSIVs (i.e., 0.01317 volume fraction per day) is assumed to leak into the reactor building. Per Reference 3, this activity is assumed to mix in 50% of the available RB free volume (4.5E6 cu ft) and be discharged to the environment via the SBGTS. The SBGTS exhaust flow is 4000 cfm

+/- 10% and its filters remove all forms of iodine and aerosols with an efficiency of 95%.

This leakage is assumed to occur for the duration of the event.

Per Reference 4, and consistent with current design basis, the analysis does not address a delay in availability of the SBGTS due to a delay in RB drawdown to achieve

-0.25 in. w.g. within the building. Reference 4 notes that the design of the reactor building and the SBGT System is to maintain the reactor building at slight negative pressure under normal and accident conditions.

During previous secondary containment leak rate surveillance, it has been observed that the reactor building pressure is maintained substantially negative (>0.2 In wc vacuum). This precludes exfiltration from the building when the SGTS system is operating.

In addition, per RG 1.183, the earliest radioactivity release occurs at 2 mins after the LOCA. Therefore, per Reference 4, the delays associated with startup of the SBGTS following a Loss of Offste Power (LOOP) co-incident with the accident will not result in radiological releases that bypass the SBGTS.

The impact of a LOOP at a more unfavorable time "significantly later" on in the accident, (such as during the fuel release phase of a LOCA), is not addressed per NRC Information Notice 93-17 (Reference 17).

The need to evaluate a design basis event assuming a simultaneous or subsequent LOOP is based on the cause/effect relationship between the two events (an example Illustrated in IN 93-17 is that a LOCA results in a turbine trip and a loss of power generation to the grid, thus causing grid Instability and a LOOP a few seconds later, i.e.,

a reactor trip could result in a LOOP). IN 93-17 concludes that plant design should reflect all credible sequences of the LOCAJLOOP, but states that a sequence of a LOCA and an unrelated LOOP is of very low probability and is not a concern.

As seen from inspection of Figures 1 and 2 the RADTRAD and PERC2 transport model for containment leakage via the SBGTS are essentially the same.

ESF leakage With the exception of noble gases, all the fission products released from the core in the gap and early in-vessel release phases are assumed to be instantaneously and homogeneously mixed in the suppression pool water at the time of release from the E-FORM l

NES-G-1 4.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO.14 fuel. Per Reference 4, a minimum sump volume of 110,000 gallons is utilized In this analysis. In accordance with RG 1.183, with the exception of iodine, all radioactive materials in the recirculating liquid Is assumed to be retained in the liquid phase. The subsequent environmental radioactivity release is summarized below:

In accordance with the station specific parameters provided in Reference 4 and the guidance provided in Reference 3, equipment carrying suppression pool fluids and located inside the Reactor Building are postulated to leak into the reactor building at twice the expected value of 10 gph. ESF leakage is conservatively assumed to start at the onset of the LOCA. Since the temperature of the recirculation fluid is less than 212 0F, ten percent (10%) of the halogens associated with this leakage become airborne and are filtered and exhausted (with 50% mixing and holdup in the RB) to the environment via the SBGTS. The chemical form of the iodine released from the sump water is 97% elemental and 3% organic.

As seen from inspection of Figures 1 and 2 the RADTRAD and PERC2 transport model for ESF leakage via the SBGTS are essentially the same.

Control Room DesignriOneration/Transoort Modelin, The control room (CR) is modeled as a single region. Isotopic concentrations in areas outside the control room envelope are assumed to be comparable to the isotopic concentrations at the control room intake locations. The CR ventilation intake corresponds to a single intake design that is utilized during both normal and emergency mode. The CR emergency ventilation system is manually initiated 40 mins after the LOCA. In accordance with Reference 4, during the initial 40 mins the CR is assumed to be on normal ventilation (unfiltered, flow rate of 2000 +/- 10%). The model utilizes a normal operation flowrate of 2200 cfm to maximize the contribution during this period.

The CR pressure boundary free volume is 81,000 cu ft. The ventilation system is designed to maintain the CR at 1/8 w.g during both normal and accident mode. The CR emergency intake flow rate is 2000+/- 10% cfm and has a filter efficiency of 99% for all forms of iodine. The model utilizes an intake flowrate of 1800 cfm to minimize control room cleanup. The unfiltered inleakage into the CR during normal and accident mode is 263 cfm which includes the 10 cfm inleakage (per SRP 6.4, Reference 12) due to Ingress/egress.

As noted in Reference 4, the atmospheric dispersion factors generated for the CR intake are representative for control room Inleakage.

l E-FORM l

NES-G-1 4.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.15 FIGURE 1 Activity Transport and Dose Model used In RADTRAD Environment Station Chimney Ret.-

MSIV-jkg Horfizonlal and Vertical MSL lines W/PF Notes:

NatDep: Natural Deposition and Elemental Iodine Plateout DW_1kg : Primary Containment leakage to RB MSIVJkg: Primary Containment leakage via MSL including externally (to RADTRAD) calculated, proprietary deposition/ plateout rates, holdup and decay in a single line modeled as 5 Tanks in series.

HS1 through HS4 are horizontal sections of the MSL.

VS1 is the vertical sections of the MSL During periods when the CR intake is not filtered, the filter efficiency is set to 0.00 Transport Model input parameters are in the Inputs and Calculation Sections herein E-FORM

NES-G-1 4.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.16 FIGURE 2 Activity Transport Model used in PERC2 to Validate and Verify RADTRAD Results Environment Station Chimney Rel.-

,,.NatDep MSIVjkg Holdu p 5~~~~~~~~~~ t~

DF me Fittered Intake

~~ESF. Ikg wIPF neke Inleacage -Ro-Reactor Building

~~~~~~~~Control Room Notes:

NatDep: NatLDep: Natural Deposition and Elemental Iodine Plateout DWjlkg: Primary Containment leakage to RB MSIVlkg: Primary Containment leakage via MSLs DF: Externally Calculated Total Deposition IPlateout DFs Holdup Volume is sum of HS1 through HS4 plus VS1 In Fig. 1 During periods when the CR intake is not filtered, the filter efficiency is set to 0.00 Transport Model input parameters are in the Inputs and Calculation Sections herein IIEmFORM -1

NES-G-1 4.02 Effective Date:

.0414100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.17 FIGURE 3 Summary Time-Line of Events of the "Base Case" following a postulated LOCA at Dresden Unit 2 or Unit 3 using Alternate Source Terms Time After LOCA l

0-2 2-30 l 30-32 32-40 40-90 90-122 2-24 1-30 Key Parameters (mim) im)

(rMm)

(min)

(hr (day) gap release from core to containment atm.

____II early-in-vessel core release to containment atm.

I

'1 containment leakage via RB to SBGTS to Stack ESF leakage via RB to l

I

l SBlGTS to Stack 1

I I' I containment leakage via Main Steam Line I

I I

I

-l-ii fumigation of Plant Stack

. _l;_____

releases

__i.'I control room unfiltered intake 1

(normal operating mode)

I

__l_l_

Control room filtered Intake I

l l_ l

.1

^-I-:

(emergo vent. mode)

]

f ____-_;

I I -

control room unfiltered *~i,.t

,,,,.t 1,'

inleakagqe.; ::N.:.;'-;..,.. :':..,,-,..,'.':'s, II E-FORM V]

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO.18 Proposed Changes to Design Basis (PART 2)

Containment Airborne Activity Per Reference 4, the containment airborne model described above in Part 1 for containment leakage remains unchanged except that the total containment leakage rate is increased from 0.016 volume fractions per day in Part 1 to 0.030 volume fractions per day. Additionally, for Part 2, the leakage reduces to half itWs value 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the postulated LOCA.

Containment Leakage via MSIVs Except as noted, the methodology / input parameters described in Part 1 for containment leakage via MSIVs remains unchanged. A parametric study based on the 5 unit concept was performed to establish the dose impact in the control room due to changes in MSIV leakage. Based on the results of this study (summarized in Appendix A of this calculation), the total leakage from all MS Lines is increased from 79.6 scfh measured @ 48 psig to 250 scfh measured @ 48 psig, allowing a maximum of 100 scfh

@ 48 psig from any one of the 4 MS lines. Additionally, in Part 2 the MS valve leakage reduces to half its value 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the postulated LOCA.

The model in Part 2 assumes a total leakage rate of 250 scfh comprised of 100 scfh from a MSL that experiences a single failure of the outboard MS valve in the shortest line, plus 100 scfh from a second MS line that is assumed to break just after the outboard valves, plus 50 scfh from a third MS line that is also assumed to break just after the outboard valve. This combination of flows maximizes the dose consequences for a total MSIV leakage of 250 scfh @ 48 psig as activity retention within the MSL increases nonlinearly with increasing residence time (decreasing flow) as depicted in Appendix A.

Note that a reference pressure of 48 psig is utilized for in-containment pressure at accIdent conditions to establish the percentage of the total allowable containment leakage (3%/Olday) that can be released via the MSIV leakage pathway. This also allows for the continued use of the current conversion factor of 111.73 to establish the MSIV leakage that would be observed at the MSIV test pressure of 25 psig.

Thus, the reference in-containment pressure is merely used to fix the allowable MSIV leakage specified in containment volume fractions per day, which is the key input in the dose analysis, and is independent of actual containment pressure.

As discussed previously, holdup is addressed using the series of five (5) tanks that represent a single MS line. Time for initiation of MSL releases to the environment was determined using a criteria of 40 minutes (i.e.; time at-which the CR is In full emergency ventilation operation) or 1/8 the time determined using a plug flow model for retention -

whichever time was smaller. For all cases considered, 40 minutes was the limiting time l

E-FORM l

NES-G-1 4.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.19 I

for initiation of MSIV releases. The average transit time for the worst line (proposed design) in plug flow is 6.8 hrs (V/F = 160 cu. ft. / 0.39075 cfm /60 min/hr). Since 40 min

< (6.8 hrs / 8), the model assumed that the leading edge would begin environmental release at 40 min after the LOCA Containment leakage via the SBGTS Per Reference 4, the methodology described above in Part 1 for containment leakage via SBGTS remains unchanged, except for the following:

• Containment leakage into the Reactor Building increases from 0.01317 volume fractions per day in Part 1 to 0.0211 volume fractions per day in Part 2.

• The SBGTS efficiency changes from 95% for aerosols, elemental and organic iodine to 99% for aerosols and 50% for elemental and organic iodine.

ESF leakage Per Reference 4, the methodology described above in Part 1 for ESF leakage via SBGTS remains unchanged, except for the following:

• ESF leakage rate into the Reactor Building Increases from 20 gph (2 times the expected leakage rate of 10gph) in Part 1 to 2 gpm (two times the proposed Technical Specification value of I gpm) In Part 2.

• The SBGTS efficiency changes from 95% for aerosols, elemental and organic iodine to 99% for aerosols and 50% for elemental and organic iodine.

Control Room DesianlOperation/Transport Modeling Per Reference 4, the methodology described above in Part 1 for Control Room modeling remains unchanged, except for the following:

• The allowable infiltration rate increases from 263 cfm in Part 1 to 600 cfm in Part 2. (both values include a 10cfm for ingress/egress)

• The CR intake filter efficiency changes from 99% for aerosols, elemental and organic Iodine to 99% for aerosols and 95% for elemental and organic iodine.

The RADTRAD transport model associated with the LOCA, for Part 1 as well as Part 2 is presented in the Figure 1 while the PERC2 transport model to check RADTRAD results is presented in Figure 2. Except as noted in Table 1, the key assumptions /

parameter values used are the same as in the uBase Case" LOCA.

ll E-FORM l

NES-G-14.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO.20 TABLE 1 Summary of Proposed Design Basis Changes Part 1 Value Part 2 Value ltem "Base Case" "Proposed Change' Notes Total Containment L 0-30d (1.6% d) 0-ld (3% dl )

1-30d (1.5* d'.)

Total MSIV leakage 0-30d (79.6 scfh) 0-Id (250 scfh)

MSIV leakage values are (0.283 %td)

(0.89 %d')

measured at 48 psig. MSIV (0.311 efin)

(0.9769 cpin) leakage rates used in this assessment assume leakage is 1-30d (125 scfh) measured on the high-pressure (0.445 %dg) side of the MSI valve.

(0.4884 cfin)

Maximum MSIV leakage from 0-30d (79.6 scth)

(0-Id) I00 scfh The current plant technical any one of the four MSLs (0.283 %d')

(0.356 %d1) specifications allow the plant to (0.311 efin)

(0.3907 qfin) have all MSV leakage from one line.

(1-30d) 50 scfh (0.178 %df)

The proposed Plant Technical (0.1 954 cfin)

Specifications will limit any one

.line to 100 seth at 48 psig Leakage from Drywell 0-30d (1.317% d"')

0-Id (2.11% d-n)

To Reactor Building 1-30d (1.055% d-')

ESF leakage 20 gph 2 gpm The actual plant allowable leakage is limited to half the values used in the analysis herein RB SBGTS Filter Eff.

HEPA filter efficiency tests performed in accordance with Aerosols 95%

99%

industry standards assure an Elemental Iodine 95*

50%

efficiency greater than 99%

Organic Iodine 95%

50%

~~~~~~~~~~~~Includes 10 cfmn for ingress/egrcss CR Infiltration rate 263 cfm 600 cfmI CR Intake Filter Eff.

_HEPA filter efficiency tests performed in accordance with Aerosols 99%

99%

industry standards assure an Elemental Iodine 99%

95%

efficiency greater than 99%

Organic Iodine 99%

95%

Il E-FORM 7

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DRE01-0D40 REV: 0

.PAGE NO.21 4.0ASSUMPTIONS / ENGINEERING JUDGEMENTS

1. It is estimated that environmental releases due to MSIV leakage will not occur until well over one hour. However, the analysis conservatively assumes that holdup of activity releases due to MSIV leakage in MSLs Is limited to 40 minutes (the time for CR emergency ventilation to manually initiated).

2. In determining the Initiating time for activity release due to convective flow patterns within the pipe, a factor of 1/8 is applied to the calculated plug flow residence time to estimate the time to breakthrough for the leading edge of the activity front. This time is compared to the manual initiation time for the CR emergency ventilation and the shorter time chosen. The 1/8 factor has been previously used within the industry to determine time to breakthrough and Is applied to only this portion of the analysis.

Activity transport through the Main Steam Lines is modeled via CSTs (continuously stirred tanks) and not as plug flow.

3. To maintain an ultimate suppression pool pH of greater than 7, credit is taken for the sodium pentaborate in the Standby Liquid Control System, which is assumed to be manually initiated via the EOPs such that the entire inventory of sodium pentaborate is delivered and mixed in the suppression pool within 24 hrs of the LOCA 5.0DESIGN INPUTS item Value Reference Source Term

1. Power level (w margin for power uncertainty)

2. Fuel Cycle Length

3. Fission Products Released

4. Iodine Fractions organic elemental particulate 3016 MWth Ref.4 24 Month Cycle per RG 1.183 per RG 1.183 0.0015 0.0485 0.95 Ref.4 Ref.3, 4 Ref.3, 4 E-FORM I

NES-G-14.02 Effective Date:

04114/00 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.22 5.FulRlaetmn

5. Fuel Release timing gap early-in-vessel per RG 1.183 Onset:

2 minutes Duration: 30 minutes Ref.3, 4 Onset:

Duration:

32 minutes 90 minutes

6. Core Activity in Ci / MWth Ref. 6 RADTRAD Nuc.No.

001:

002:

003:

004:

005:

006:

007:

008:

009:

010:

011:

012:

013:

014:

015:

016:

017:

018:

019:

020:

Nuclide Co-58 Co-60 Kr-85 Kr-85m Kr-87 Kr-88 Rb-86 Sr-89 Sr-90 Sr-91 Sr-92 Y-90 Y-91 Y-92 Y-93 Zr-95 Zr-97 Nb-95 Mo-99 Tc-99m Core Activit O.OOOE+00 O.OOOE+00 4.364E+02 6.772E+03 1.291E+04 1.81 5E+04 7.096E+01 2.428E+04 3.528E+03 3.081 E+04 3.362E+04 3.625E+03 3.155E+04 3.377E+04 3.942E+04 4.443E+04 4.497E+04 4.464E+04 5.121 E+04 4.484E+04 RADTRAD Nuc.No.

021:

022:

023:

024:

025:

026:

027:

028:

029:

030:

031:

032:

033:

034:

035:

036:

037:

038:

039:

040:

Nulide Ru-103 Ru-1 05 Ru-106 Rh-105 Sb-127 Sb-129 Te-127 Te-127m Te-129 Te-129m Te-131m Te-132 1-131 1-132 1-133 1-134 1-135 Xe-133 Xe-1135 Cs-134 Core Activity 4.311 E+04 3.034E+04 1.837E+04 2.882E+04 2.999E+03 8.877E+03 2.986E+03 4.060E+02 8.735E+03 1.300E+03 3.955E+03 3.850E+04 2.710E+04 3.914E+04 5.501E+04 6.035E+04 5.157E+04 5.282E+04 2.144E+04 8.009E+03 RADTRAD Nuc.No.

041:

042:

043:

044:

045:

046:

047:

048:

049:

050:

051:

052:

053:

054:

055:

056:

057:

058:

059:

060:

Nuclide Cs-136 Cs-137 Ba-139 Ba-140 La-140 La-141 La-142 Ce-141 Ce-143 Ce-144 Pr-143 Nd-147 Np-239 Pu-238 Pu-239 Pu-240 Pu-241 Am-241 Cm-242 Cm-244 Core Acivitv 2.379E+03 4.928E+03 4.888E+04 4.714E+04 5.055E+04 4.447E+04 4.286E+04 4.465E+04 4.1 01 E+04 3.682E+04 3.963E+04 1.800E+04 5.587E+05 1.768E+02 1.474E+01 2.001E+01 6.700E+03 9.857E+00 2.285E+03 1.621 E+02 Drywell Airborne Activity Leakage

7. Volume of Primary Containment

8. Drywell Surface Area

9. Elemental Iodine Kw mass transfer coefficient

10. Primary Containment Leak Rate 1.58E5 ft3 32,250 ft2 4.9 meters / hr 1.6% day" Ref.4 Ref.4 Ref.10 Ref.4

,I E-FORM I

NES-G-14.02 Effective Date:

04,14100 DESIGN ANALYSIS NO. DREO=-04 REV: 0

.PAGE NO.23

11. Correlation of BWR effective natural deposition decontamination coefficients with reactor thermal power for design basis accidents (10 percentile) from Ref. 15 Release Phase gap gap early in-vessel gap + early in-vessel gap + early in-vessel gap + early in-vessel gap + early in-vessel gap + early in-vessel Time Interval (hr) 0-0.5 0.5-2 0.5-2 2-5 5-8.33 8.33-12 12-19.4 19.4-24

~eosrnnhr 1 1.285[exp(-21 19/P(MWh)]

1.161 [exp(-22741P(MWf,)]

0.520[exp(-21 73/P(MW1,)]

1.551 [exp(-1 507/P(MWm,)]

0.836[exp(-1 051 /P(MW,,,)]

0.780[exp(-1 31 6/P(MW,h)]

0.778[exp(-1 5481P(MWt)]

O.780[exp(-1 6861P(MWh)]

12. Leak Rate by MSIVs @ 48 psig.

13. MSIV flow correction between 79.6 scfh Ref.4 Ref.4 1.73 25 psig to 48 psig

14. Natural Deposition Constants in MSLs for Dresden / Quad Cities DBA LOCA with AST; MS Line with Outboard Valve Failure (from Ref.13)

Perod Ihourj

- 0.0333-1.0333 1.0333-2.811 2.811 - 5.033 5.033 -10.0333 10.0333 - 24.033 24.0333 - 50.0333 50.0333-69.01 69.01 -138.92 138.92 - 277.81 277.81 - 720.033 Aerosols Lambda ( hr-'

1.8260E+00 1.7860E+00 1.7864E+00 1.8079E+00 1.8475E+00 1.9337E+00 2.0855E+00 8.6971 E-01 8.2767E-01 7.8969E-01 Elemental Iodine Lambda I hr1" 1.2695E-01 1.3176E-01 1.4075E-01 1.5283E-01 1.8371 E-01 3.0375E-01 7.1498E-01 1.M7E+00 1.2246E+00 1.2246E+00

15. Natural Deposition Constants in MSLs for Dresden I Quad Cities DBA LOCA with AST; Representative MS Line with No Single Failure of Isolation Valve - (from Ref.13)

Period (hour) 0.0333-1.0333 1.0333-2.811 2.811 -

5.033 Aerosols Lambda I hre) 1.8454E+00 1.8049E+00 1.8053E+00 Elemental Iodine Lambda (he 1 1.2829E-01 1.3316E-01 1.4224E-01

-E-FORM I

NES-G-1 4.02 Effective Date:

0414=00 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.24 5.033 - 10.0333 10.0333-24.033 24.0333 - 50.0333 50.0333-69.01 69.01 -138.92 138.92-277.81 277.81 - 720.033 1.8271 E+00 1.8671 E+00 1.9542E.00 2.1 076E+00 B.7893E-01 8.3644E-01 7.9805E-01 1.5445E-01 1.8568E-01 3.0697E-01 7.2255E-01 1.2387E+00 1.2376E+00 1.2376E+00 16 Decontamination Factors in MSLs for Dresden / Quad Cities DBA LOCA with AST; MS Line with outboard Valve Failure: MSIV Leakaae :100 scfh@ 48 osi-(from Ref. 13)

Aerosols Elemental Iodine Period thourA 0.0333 - 1.0333 1.0333-2.811 2.811-5.033 5.033 - 10.0333 10.0333-24.033 24.0333-50.0333 50.0333 - 69.01 69.01 -138.92 138.92 - 277.81 277.81 -720.033 1.962E+01 1.874E+01 1.874E+01 1.922E+01 2.010E+01 1.227E+02 1.518E+02 1.775E+01 1.606E+01 1.465E+01 2.095E+00 2.146E+00 2.245E+00 2.381 E+00 2.756E+00 1.284E+01 8.772E+01 4.418E+02 4.406E+02 4.406E+02 17 Volume (ft3) of shortest "fifth unit concept pipe" (as defined in Ref.13) assuming outboard valve failure (from Ref.13)

S 0

S 0

0 Section 1 (horizontal)

Section 2 (horizontal)

Section 3 (horizontal)

Section 4 (horizontal)

Section 5 (vertical) 9.42 16.87 16.87 14.28 102.14 18 Volume (ft3) of representative "fifth unit concept pipe" (as defined in Ref.13) assuming outboard valve closure (from Ref. 13)

Section 1 (horizontal)

Section 2 (horizontal)

Section 3 (horizontal)

Section 4 (horizontal)

Section 5 (vertical) 9.91 32.83 25.14 25.14 101.78 19 SBGTS adsorption/filtration efficiency 95% (all species)

Ref.4 E-FORM -

NES-G-14.02 Effective Date:

04114/00 REV: 0 PAGE NO.25 IDESIGN ANALYSIS NO. DREOI-0040 20 21 22 Secondary Containment Volume Fraction of Sec. Cont. Available for Mixing Plateout/Deposition In Containment organic 0

elemental NL aerosol PC 4.5E6 ft3 0.5 Ref.4 Ref.3, 4 Ref.4 JREG-0800,SRP 6.5.2 iwers Model (10 percentile)

Ref.1 0 ESF Leakage

23.

Suppression Pool Volume 24 ESF Leak Rate (with factor of 2 margin) 25 Fraction of ESF leakage that becomes airborne 26 Fraction of iodine form of activity released from ESF elemental organic

27.

Duration of ESF leakage 0

28.

Fraction of Secondary Containment available for ESF leakage mixing 0.

1 10,000 ft3 20 gph 0.1 0.97 0.03 Ref.4 Ref.4 Ref.3, 4 Ref.3, 4 Ref.3, 4

-30 days

.5 Ref.4 Ref.3. 4 Control Room 29 Pres. boundary envelope free volume 30 Intake Flowrate 81,000 ft3 Ref.4 Ref.4 Normal operation unfiltered Emergency filtered intake 31 Unfiltered inleakage Normal operations Emergency Ventilation mode 32 Intake Filter Efficiency (all species) 33 Recirculation rate through filters 34 CR Breathing Rate 2000 +/- 10%

2000 +/-10%

Ref.4 263 cfm 263 cfm 990%

Ocfm RADTRAD Default Ref.4 Ref.4 Ref.7 I

E-FORM l

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREOI-0040 REV: D PAGE NO.26 35 DRE Units 2 &3 CR Atmospheric Dispersion Factors (sec/m3)

Ref.4 Release Point MSIV Leakage Station Chimney (non-fumigation)

Station Chimney (0 - 0.5 hr fumigation) 0-2hour 2-8hour 8-24 housr 1.24E-3 1.08E-3 5.29E-4 1.41 E-8 5.57E-9 3.50E-9 1-4dav 4-30dav 3.43E-4 2.72E-4 1.28E-9 3.01 E-1 0 4.17E-04 N1A N/A N/A NWA Site Boundary

36.

Breathing Rate RADTRAD Default Ref.7

37.

DRE Units 2 &3 Site Boundary Atmospheric Dispersion Factors (sec/m3) Ref.4 EAB Release Point 0- 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> MSIV Leakage Station Chimney (non-fumigation)

Station Chimney (O - 0.5 hr fumigation)

LPZ 3.59E-6 6.98E-5 Release Point MSIV Leakage Station Chimney (non-fumigation)

Station Chimney (0 - 0.5 hr fumigation) 0-2 hour 2-8 hour 8 - 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 2.10E-5 9.08E-6 5.98E-6 2.48E-6 1.17E-6 8.08E-7 I - 4 dav 4-30dav 2.41 E-6 6.56E-7 3.58E-7 1.1 2E-7 8.72E-6 N/A NIA N/A NIA II E-FORM

NES-G-1 4.02 Effective Date:

04114100 PAGE NO.27 I

DESIGN ANALYSIS NO. DRE01-0040 REV: 0

1 6.01REFERENCES

1.

10CFR50.67, "Accident Source Term".

2.

TID 14844, 'Calculation of Distance Factors for Power and Test Reactor Sites",

1962

3.

Regulatory Guide 1.183, Revision 0, 'Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors", July 2000.

4.

EXELON Transmittal of Design Information No.ER2002-9994, 'Dresden Station Concurrence with the Design Inputs as established for Alternate Source Term (AST) LOCA Analysis" Revision 1, 7/31/02

5.

Regulatory Guide 1.49, Revision 1, 'Power Levels of Nuclear Power Plants".

6.

GE Task Report No.

"Dresden and Quad Radiation Sources and GE-NE-A22-00103-64-01, Rev 0, Project Task Report:

Cities Asset Enhancement Program -

Task T0802:

Fission Products" Dated August 2000.

7.

Industry Computer Code RADTRAD 3.02a, 'A Simplified Model for Radionuclide Transport and Removal and Dose Estimation" developed by SNL

8.

EPA-520/1-88-020, 1988, Federal Guidance Report No.11, 'Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion and Ingestion".

9.

EPA-420-R-93-081, 1993, Federal Guidance Report No.12, 'External Exposure to Radionuclides in Air, Water and Soil"

10.

NUREG 0800, 1988, Standard Review Plan, Containment Spray as a Fission Product Cleanup System", Section 6.5.2, Revision 2.

11.

Cline, J.E. "MSIV Leakage - Iodine Transport Analysis" SAIC, August 20, 1990

12.

NUREG 0800, Standard Review Plan, "Control Room Habitability System", SRP 6.4, Revision 2.

13.

Stone and Webster Calculation 08645.7022-UR(B)-001, Rev.0, 'Modeling Gravitational Settling / plateout in Main Steam Lines at Dresden 2&3 Quad Cities 1 &2" E-FORM

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREO010040 REV: 0 PAGE NO.28

14.

Stone and Webster Computer Program PERC2, NU-226, Version 00, Level 01, "Passive / Evolutionary Regulatory Consequence Code

15.

NUREG/CR-6189 "A Simplified Model of Aerosol Removal by Natural Processes in Reactor Containments*, July 1996

16.

S&W Calculation No. DRE02-0033, Revision 0, "Ultimate Suppression Pool pH following a Loss of Coolant Accident.

17.

NRC Information Notice 93-17, Revision 1, "Safety Systems Response to Loss of Coolant and Loss of Offsite Power," March 25, 1994 (original issue March 8, 1993).

I E-FORMW

]

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO. 29 7.OCALCULATION This section discusses the following:

data pre-processing computations required for input to RADTRAD and PERC2 RADTRAD and PERC2 output files with execution date and time stamps detailed output activity and doses from RADTRAD and PERC2 As stated in the Methodology Section, doses are calculated with the RADTRAD computer program and validated with the PERC2 program.

Provided below is the development and description of each of the key RADTRAD and PERC2 inputs for the activity transport and dose models used to calculate the site boundary and control room dose at Dresden using Alternate Source Terms.

The RADTRAD input structure is as follows:

1. Compartment definition, its associated volume, and relevant activity removal rates and coefficients.

2. Pathway identification and associated flows and cleanup efficiencies in accumulators in flow streams (pathways) between compartments

3. Dose Location(s) - defined compartment(s)

4. Source Terms - equilibrium shutdown fuel activity, accident release fractions, timing and activity to dose conversion factors)

The Dresden DBA LOCA activity transport and dose consequence RADTRAD model is broken up as follows (see the computer run output table notes for further clarification):

Ground level primary containment isolation valve leakage via four (4) MS Lines.

Elevated release of primary containment leakage into the reactor building, with mixing, holdup and subsequent treatment from the SBGTS.

Elevated release of ESF leakage into the reactor building and subsequent treatment from the SBGTS E-FORM :

NES-G-14.02 Effective Date:

0414/00 DESIGNANALYSISNO. DRE01-0040 REV: 0 PAGE NO.30 Provided below are the calculations of the key inputs to RADTRAD for each of the 3 activity transport /dose models. Similar to the Methodology Section, the Calculation Section Is broken into two parts.

Part 1: The base case entails the assessment using TAltemate Source Terms" and current Dresden design licensing basis plant parameters (identified by EXELON via Reference 4).

Part 2: As noted in Table 1 of the Methodology Section, Part 2 is the base case with the following proposed modifications:

Increased allowable MSIV leakage from a total of 79.6 scfh @ 48 psig in all four lines to 100 scfh measured @ 48 psig in one line with a total of 250 scfh measured

@ 48 psig in all 4 MSLs increased allowable control room inleakage from 263 cfm to 600 cfm (includes 10 cfm for ingress/egress) increased allowable containment leakage from 1.6% volume per day to 3% volume per day reduced SBGTS charcoal iodine filter efficiency for organic and elemental iodine from 95% to 50%

increased credit taken for the SBGTS HEPA filter efficiency from 95% to 99%

reduced control room charcoal Iodine filter efficiency for organic and elemental iodine from 99% to 95%.

increased allowable ESF leakage from 10 gph to 1 gpm RADTRADIPERC2 ore-processing. Output File lists and detailed Results for Part 1 Containment Atmosphere Activity Leakage Rate Calculations for "Base Case" Provided below are the estimated activity leakages from containment for the Main Steam Lines and stack releases for the 'Base Case" with Proposed Design Basis changes.

Base Case : MSL Release (assumed conservatively to be from one line)

Calculated below is the MSL leakage rate assumed to be across one valve. The outboard valve is assumed to fail open, resulting in less deposition/plateout. Following E-FORM l

NES-G-14.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DRED1-0040 REV: 0 PAGE NO.31 below is a description of how leakage is measured and what leakage is actually modeled in RADTRAD.

MSL Test leakage rate With Pres. Correction Factor for Factor 46 scfh x 1.73 =

48psig Total MSL Flow out Containment 79.6 soth x 14.7 psia 1 (14.7 + 48) psla =

18.658 cfh / 60 min/hr =

18.658 ft3/hr x 24 hr/day /1.58E5tM x 100=

46 sofh 79.6 scfh 18.658 cfh 0.31096 cfm 0.283 /oday The test conditions for MSIV allowable leakage for DRE is as follows:

25 psig MSIV 0 psig (14.7 psla)

Measurement TEST The flow rate input to RADTRAD is the leakage rate measured at peak pressure (48 psig) with leakage model shown below:

48 psig Measurement MSIV O psig (14.7 psia)

RADTRAD Therefore the leakage rate input to RADTRAD consistent with the containment activity release rate in terms of volume fractions per day is expressed as:

X cfm = test leakage x peak correction factor x 14.71(14.7+48) 1(60 min/hr).

Containment leakage to Reactor Building Leakage to RB is the total drywell leakage minus that which leaks into the MSL line:

Total Containment Leakage Containment Lkg to RB 1.6 %I'e6day 1.317 1/day 1.6 %Iday - 0.283 Va/16day E-FORM I

NES-G-1 4.02 Effective Date:

0411140 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.32 Elemental Iodine Removal Coefficient Approximately 5% (0.0485) of the iodine activity released to the containment following the LOCA assuming AST methodology is elemental.

Natural deposition of the elemental iodine released to containment is estimated assuming the methodology outlined in NUREG-0800 Standard Review Plan 6.5.2, Rev.2 (pg 6.5.2-10):

The expression for wall deposition Is A

A,, = Kw* -

WV A.

= first order removal coefficient by wall deposition A

= wetted surface area 32,450 f 2 -

V

= drywell net free volume (1.58E5 fe3)

Kin

= mass transfer coefficient from SRP 6.5.2 (4.9 m/hr)

Aw

= 4.9 m/hr (3.2808 ft /m) (32,250 f 2) / (1.58E5 ft3) = 3.28 hr' Time when Elemental Iodine DF of 200 Is reached In Containment Atm.

The value of 3.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to reach a DF of 200 for elemental iodine Is achieved by semi-log Interpolation.

A test run of PERC2 was made with estimated cutoff times.

Interpolation between two time periods from this test run resulted in a DF = 200 in about 3.1 hours1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. The value of 3.1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to terminate the elemental deposition lambda was then entered to the final PERC2 model run and verified as shown below:

As stated in RG 1.183 Rev.0 (Ref.3), the cutoff time for elemental iodine plateout in containment is based on NUREG-0800 SRP 6.5.2, Rev.2 (Ref.10). The SRP states that the iodine decontamination factor, DF, is defined as the maximum concentration in the containment atmosphere divided by the concentration of iodine in the containment atmosphere at some time after decontamination. The maximum DF Is 200 for elemental iodine. The effectiveness in removing elemental iodine shall be presumed to end at that time, post LOCA, when the maximum elemental iodine DF is reached.

Using the core halogen release fractions in Table 1 of RG 1.183 Rev.0 (0.05 plus 0.25 =

0.3), the fraction of elemental Iodine airborne In the containment (0.0485) and a tracer halide 1-131, the elemental plateout cutoff time is:

Initial elemental 1-131 inventory released to containment E-FORM I

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREo1-0040 REV: 0 PAGE NO.33

.~~~~~~~~~~~~~~~~~~~~~

= 1-131 Activity / MWth x P(MWth) x fraction released x form fraction

= 2.71 0E4 CVMWth x 3016 MWth x 0.3 x 0.0485 =1.1892E6 Ci From run RO04OdreOl5d.out at interval 7 (3.1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) gap Early In-Vessel Total 0.0047361 C/m3 1.3354 CU m3 1.3401 CY e 3 1-131 Activity (Ci) = 1-131 Concentration x Volume (m3)

= 1.3401 C/m3 x 4474.062 m3 = 5996 Ci Drywell Volume = 1.58E5 ft3 or 4474.062 m3 DF (T=3.1) = 1.1892E6 Ci /5996 Ci = 198.3 or essentially 200 Calculation of "Powers Model" Containment Aerosol Deposition Coefficients Using the time dependent equations in Datum #9 from NUREG/CR-6891 and the Reactor Power level in Datum #1 (3016 MWth), the following natural deposition lambda's (hr') are calculated for Dresden Units 2 and 3:

Phase GAP GAP E l-V G+E I-V G+E I-V G+E I-V G+E I-V G+E I-V e

Applicable Period Fromphr)

To(hr) 0 0 0.5 0.5 2

0.5 2

2 5

5 8

8 12 12 19.4 19.4 24 a C1 1.285 1.161 0.52 1.551 0.836 0.78 0.778 0.78 Constants

=

C2 2119 2274 2173 1507 1051 1316 1548 1686 I

Lambda hr' 0.636464 0.54624 0.252987 0.941041 0.590018 0.504191 0.465664 0.445981 Site Boundary Dose Assessment for "Base Case" The Exclusion Area Boundary (EAB) and Low Population Zone (LPZ) are calculated by RADTRAD using the equations described in the Methodology Section.

RADTRAD requires the completed transpot model and time dependent dispersion factors as input, while breathing rates are RADTRAD default values.

The EAB 'Worst-case 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window" is described In RG 1.183 Rev. 0 as:

11 E-FORM I

NES-G-14.02 Effective Date:

04114/00 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.34 ft The maximum EAB TEDE for any two-hour period following the start of the radioactivity release should be determined and used In determining compliance with the dose criteria in 10 CFR 50.67. The' maximum two-hour TEDE should be determined by calculating the postulated dose for a series of small time increments and performing a "sliding sum over the increments for successive two-hour periods."

RADTRAD calculates the " worst-case 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window TEDE" internally If the worst 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> x/Q is used for the duration of the accident release, however, since each pathway is run separately (i.e., containment Ikg via stack, ESF leakage an MSL leakage),

RADTRAD provides three worst-case 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window" periods. Since the MSL leakage dominates the dose consequence, it's calculated "worst-case 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window" period is used for the remaining two pathways. To force RADTRAD into using the same 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window period for all three leakage pathways the x/Q value in the two remaining pathways is set to zero (0) except for the 'worst-case 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window" period calculated by RADTRAD in the MSL pathway run. As a result, the EAB TEDE can be taken directly out of RADTRAD without further assessment, since the non-zero appropriate 2-hour xIQ value Is only used only during the "worst-case 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> window" period.

NOTE: Ultimately, PERC2 was run for the Part 2 models only. The dose results for Part 2, as would be expected, come much closer to the design dose limits discussed in the Acceptance Criteria section than the doses calculated in Part 1. Additionally all of the modeling in Part 2 is the same as Part 1 with the exception of 2 additional MSL lines).

Therefore by using PERC2 to validate the RADTRAD results In Part 2, the results of Part 1 are also validated.

l EmFORM

NES-G-14.02 Effective Date:

-041 400 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.35 Computer Output Files for Part 1 File Name Time end Date StamP Run Description DRE Units 2 and 3 Part I Base Case R0040dreOol.out RADTRAD Version 3.02a run on 7/24/2002 at 13:54:48 Core gap release 4 Cont. Aft. 4 RB 4 SBGT 4 Stack 4 Environ. (EAB, LPZ and CR)

RO040dreOO2.out RADTRAD Version 3.02a run on 7/24t2002 at 14:01:07 E I-V core release 4 Cont. Atm. 4 RB 4 SBGT 4

Stak 4 Environ. (EAB, LPZ and CR)

R0040dreOO3.out RADTRAD Version 3.02a run on 712412002 at 14:07:27 ESF 4 RB 4 SBGTS 4 Stack 4 Environ (EAB, LPZ and CR)

RO40dre304a.out RADTRAD Version 3.02a run on 7/2412002 at 14:12:47 Core gap release 4 Cont. Atm. 4 MSL 4 Environ (EAB,and CR)

ROD40dreOD4b.out RADTRAD Version 3.02a run on 712412002 at 16:54:49 Core gap release 4 Cont. Atm. 4 MSL 4 Environ (LPZ)

RD040dre05a.oul RADTRAD Version 3.02a run on 7/2412002 at 14:26:31 E -V core release 4 Cont. Atm. 4 MSL 4 Environ (EABand CR)

R0040dreO05b.out RADTRAD Version 3.02a run on 7/24J2002 at 17:09:39 E I-V core release 4 Cont. Atm. 4 MSL 4 Environ (lZ)

I E-FORM I

NES-G-14.02 Effective Date:

0414100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO. 36 Table 2 Output dose results for "Base Case" from RADTAAD Control Room Operator Dose (rem)

Whole Body Thyroid TEDE Site Boundary EAB Dose (rem)

Whole Thyroid TEDE Body Site Boundary LPZ Dose (rem)

Whole Body Thyroid TEDE 1-131 Activty (Ci)

CONT gap e i-v 7.52E-05 8.061E.05 1.21 E-02 1.98E-01 2.1 OE-01 1.21 E-01 2.62E-04 1.21 E-01 2.90E+00 1.42E+01 1.71 E+01 5.47E-03 2.241E-05 5.50E-03 1.21 E-01 8.63E-01 9.83E-01 5.18E-03 7.71 E-02 8.23E-02 8.48E-03 1.09E-01 1.1 8E-01 2.36E-01 1.35E+00 1.59E+00 5.51 E-01 3.10E+00 3.65E+00 1.59E-02 1.65EO1 1.81 E-01 3.19E-02 2.93E-41 3.24E-01 2.86E-03 4.51 E-02 3.40E-03 5.34E-02 5.68E-02 7.76E-02 3.48E-01 4.26E-01 1.51 E-01 7.15EO01 8.66E-01 6.36E-03 6,45E-02 7.091E-02 9.1 9E-03 8.82E-02 9.741E-02 1.98E.02 1.23E+03 I1.85E+02 9.09E+02 1.09E+03 MSL gap e I-v ESF 1.05E107 6.OOE.04 1.901E-05 Tota 2.10E-01 1.73E+01 I1.27E-04.2.40E-02 8.74E-04 2.OOE-01 5.26E+00 ILI 1.98E-04 4.17E-02 1.48E-03 1.02E-01 1.33E+00 L I

7.3TIE+02 3.06E+03 E-FORM

NES-G-14.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO.37 RADTRAD)PERC2 Pre-processing, OutQut File lists and detailed Results for Part 2 All calculations performed above In Part 1 are valid for Part 2 except as noted below:

Containment Atmosphere Activity Leakage Rate Calculations for "Base Case with Proposed Design Basis Changes" A parametric study based on the 5th unit concept was performed to establish the dose impact in the control room due to changes in MSIV leakage. Based on the results of this study (summarized in Appendix A of this calculation), the total leakage from all MS Lines is increased from 79.6 scfh measured @ 48 psig to 250 scfh measured @ 48 psig, allowing a maximum of 100 scfh @ 48 psig from any one of the 4 MS lines.

Additionally, in Part 2 the MS valve leakage reduces to half its value 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the postulated LOCA.

The model in Part 2 assumes a total leakage rate of 250 scfh comprised of 100 scfh from a MSL that experiences a single failure of the outboard MS valve in the shortest line, plus 100 scfh from a second MS line that is assumed to break just after the outboard valves, plus 50 scfh from a third MS line that is also assumed to break just after the outboard valve. This combination of flows maximizes the dose consequences for a total MSIV leakage of 250 scfh @ 48 psig as activity retention within the MSL increases nonlinearly with increasing residence time (decreasing flow) as depicted in Appendix A.

MSL total allow. leakage e test press With Correction Factor for 48 psig Total MSL Flow out of Containment Allowable leakage I MSL 0 48 psig Single Line flow from 'worst Une*

and from the 1" "remalning line" Single Une flow from 2'd Remaining3 line 145 scfh x 1.73 =

250 scfh x 14.7 psia l(14.7 + 48 ) psla =

58.612 cfh 160 minrhr =

68.612 ft34ir 24 hr/day / 1.58E5 ft3 x 1 00% =

100 /250 x 0.97687 =

50 / 250 x 0.97687 =

145 scfh 250 scth 58.612 cfh 0.97687 cfm 0.8903 %Wday 100 scfh 0.3907 cfm 0.1954 cfm Containment leakage to Reactor Building Leakage to RB is the total drywell leakage minus that which leaks into the MSL lines:

Total Containment Leakage Containment Lkg to RB 3 %/61day 2.11 %/day 3 %fday - 0.8903 %/day l

E-FORM l

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREOl-0O REV: 0 PAGE NO.38 Computer Output Files for Part 2 RADTRAD Output File Name Time and Date Stamp un Description DRE Units 2 and 3 Part 2 *Base Case with Proposed Design Changes" R0040dreO06.out RADTRAD Version 3.02a run on 7125J2002 at 9:10:14 core gap release -

Cont Alm. -

RB -

SBGT

__ 4 Stack 4 Environ. (EAB, LPZ and CR)

R0040dreO07.out RADTRAD Version 3.02a run on 712512002 at 9:16:30 E IV core release 4 Cont Aim. 4 RB 4 SBGT 4 Stack 4 Envron. (EAB, LPZ and CR)

R0040dreO8.out RADTRAD Version a02a run on 7/2412002 at 14:52:51 ESF -

RB 4 SBGTS 4 Stack 4 Environ (fEAB, LPZ and CR)

R0040dreO09a.out RADTRAD Version 3.02a run on 74/202 at 14:58:11 core gap release 4 Cont. Atm. 4 100 scfh Worst MSL 4 Environ (EAB,and CR)

R0040dreOo9b.out RADTRAD Version 3.02a run on 712412002 at 17:23:37 core gap release 4 Cont. Atm. 4 4 100 sclh Worst MSL 4 Environ (LPZ)

R0040dreO10a.out RADTRAD Version &02a run on 7/2412002 at 15:11:50 E IV release 4 Cont. Alm. 4 4 100 scfh Worst MSL 4 Environ (EAB,and CR)

R004OdreOlOb.out RADTRAD Version 3.02a run on 7J2412002 at 17:36:57 E I-V release 4 Cont. Atm. 4 4 100 scfh Worst MSL 4 MSLs 4 Environ (LPZ)

R0040dreOl la.out RADTRAD Version 3.02a run on 7124/2002 at 15:25:47 core gap release 4 Cont Am. 4 100 scflh Rernaining MSL 4 Env ron (EABand CR)

R0040dreOl lb.out RADTRAD Version 3.02a run on 712412002 at 17:50:16 core gap release 4 Cont Atm. 4 100 scfh Remainino MSL 4 Environ (LPZ)

R0040dreOl2a.out RADTRAD Version 3.02a run on 7124/2002 at 15:39:42 E l-release 4 Cont. Alm. 4 100 scth Remaining MSL 4 Environ (EAB and CR)

R0040dreOl2b.out RADTRAD Version 3.02a run on 7/24/2002 at 18.03:36 E I-V release 4 Cont. Atm. 4 100 scfh Remnaining MSL 4 Environ (LPZ)

R004OdreO13a.out RADTRAD Version 3.02a run on 7124/2002 at 15:53:29 core gap release 4 Cont. Atm. 4 50 scfh Rernaining MSL 4 Environ (EABand CRl R0040dreO13b.out RADTRAD Version 3.02a run on 7124t2002 at 18:16:52 core gap release 4 Cont. Atn. 4 50 scfh eAiAne7ina MSL 4 Environ A

LPZm RW040dreO14a.out RADTRAD Version 3.02a run on 7/2410Q2 at 1607:11 E l-V release 4 Cont. Atm. 4 50 seth Rernaininc MSL -) Environ (EAB~and CR)

ROD40dre0I4b.out RADTRAD Version 3.02a run on 7124t2002 at 18:30:11 E l-release 4 ConL. Atm. 4 50sclh Remaining MSL 4 Environ (LPZ)

I E-FORM j

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.39 PERC2 Output File Name Tine and Date Stamp Run Description DRE Units 2 and 3 Part 2 oBase Case" with Proposed Design Basis Changes R004OdreOl5c.out PERC2 Version 3.02a run on 07125102 at O9:5101 Cont. Atm. -

RB -

SBGT -

Stack 4 Environ. (CR thy from Infiltration)

ROD40dreOl5p.out PERC2 Version 3.02a run on 07125102 at 09:5101 Cont. Atm. 4 RB 4 SBGT 4 Stack 4 Environ. (UO & Activity Released to Ew.)

R0040dreOl5d.out PERC2 Version 3.02a run on 07/25/02 at 09:5101 core gap release 4 Cont. Atm. (Concentrations)

R0040dreOl6c.out PERC2 Ver. 00, Lev. 01 run on 07125/02 at 09:58:54 Cont. Am. 4 RB 4 SBGT 4 Stack 4 Environ. (CR thyroid from Intake)

R0040dreO16p.out PERC2 Ver. 00, Lev. 01 run on 07/25/02 at 09:58:54 Cont. Atm. 4 RB 4 SBGT 4 Stack 4 Environ. (UO & Activity Released to Env.)

R0040dreOl7c.out PERC2 Ver. 00, Lev. 01 run on 07f25102 at 10:06:45 ESF 4-3 RB 4 SBGTS 4 Stack 4 Environ (CR Intake & infiltration)

R004OdreOl7p.out PERC2 Ver. 00,Lev.01 run on 07/25/02 at 10.06:45 ESF 4 RB 4 SBGTS 4 Stack 4 Environ (VO 8&

Activity Released to Env.)

R0040dreOl1&.out PERC2 Ver. O, Lev. 01 run on 07125102 at 10:10:42 Cont. Atm. 4 100 sclh Worst MSL 4 Environ (CR thyroid trom hfiltration)

R004OdreO18p.out PERC2 Ver. 00, Lev. 01 run on 07125102 at 10:10:42 Cont Atm. 4 100 scfh Worst MSL 4 Environ (Input file text I Output text & Activity Released to

~~ ~~~Env.)

R0040dreO~lc.out PERC2 Ver. 00, Lev. 01 run on 07/25102 at 10:18:33 Cont. Atm. 4 100 sctl Worst MSL 4 Environ (CR thyroid from Intake)

R0040dreO19c.out PERC2 Ver. 00, Lev. 01 run on 07/25102 at 10:18:33 Cont. Atm. 4 100 scth Worst MSL 4 Environ (Input file text I Output text)

I E-FORM

NES-G-14.02 Effective Date:

04=l4100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO. 40 Table 3 Output dose results for "Base Case with Proposed Design Basis Changes" from RADTRAD Control Room Operator Dose (rem)

Whole Body Thyroid TEDE Site Boundary EAB Dose (rem)

Whole Body Thyroid TEDE Site Boundary LPZ Dose (rem)

Whole Body Thyroid TEDE 1-131 Activity (C13 CONT gap e i-V 1.081E-04 7.93g-06 1.16E-04 MSL (wi-100 sclh) gap e I-v MSL (ri-100 scfh) gap e I-v MSL (r-50 scfh) gap el-v 1.50E-02 2.31 E-01 2.46E-01 1.21 E-02 1.91 E-O1 2.03E-01 3.21E-03 5.36E-02 5.68E-02 1.09E-01 4.1 OE-04 I1.09E-01 8.54E+00 5.06E+01 4.72E+e00 2.29E+01 2.76E+01 1.14E+O0 5.42EO 6.55E+00 4.03E-03 2.60EZ05 4.061E-03 3.59E-01 2.47E+0 2.83E+00 1.851E-01 1.22E+00

.1.41 E+00 3.97E-02 2.39E-01 2.79E-01 8.1 OE-03 I1.19E-01 1.281E-01 1.46E-02 1.93E-01 8.69E-03 9.§§E-02 1.05E-01 6.92E-04 6.39E0 7.09E-03 1.42E-01 7,64E-01 9.06E-01 1.28E+00 7.30EO00 8.58E+00 5.36E-01 2.84E+D0 3.38E+i00 3.45E-02 1.49E,-01 1.83E-01 1.37E-02 1.59E-01 1.72E-01 7.01 E-02 6.23E-01 6.93E-01 3.1 OE-02 2.61 E-01 2.92E-01 2.04E-03 1.44E-09 1.64E-02 3.82E-03 5.61 E:02 5.99E-02 4.34E-03 6.38E-02 6.81 E-02 3,391E-03 5.26E-L2 5.59E-02 8.77E-04 1.53E-02 6.34E..02 2.9612-01 3.59E-01 2.49E-01

.1.17E+00 1.42E+00 1.23E-01 5.77E-01 7.01 E-01 2.43E-02 I1.14E-01 1.38E-01 6.13E-03 6.90E-02 7.51 E-02 1.46E-02 1.29E-01 1.43E-01 8.08E-03 8.02E-02 8.83E-02 1.67E-03 1.85E-02 2.01 E-02 4.04E+02 2.27E+03 2.67E403 1.58E+02 7.83E+02 9.41 E+02 I.26E+02 6.20E-+02 7.46Ei.02 5.23E+01 2.54E+02 3.06E+02 ESF 4.91E 06 3.67E-02 1.16E-03 2.56E 03 Totl 5.05E-01 8.49E+01 4

4.36E-01 Note: Summary of proposed changes to OBase Case Iis presented in Table 1 1-25E+-00 4.1 5E02 1.43E+Oljj1~

2.2M2.47E+00 7.84E-02 2.02E-01 5.08E.O+0 jjj 4.30E+04 4.77E+04 E-FORM j

NES-G-14.02 Effective Date:

04/4tw DESIGN ANALYSfS NO. DREOI-0040 REV: 0 PAGE NO.41

. I Table 4 PERC2 01t ut Versus RADTRAD: Control Rm Thyrold Dose and Total Activif Released to Environment PERC2 Thyroid Dose (rem) intake Infiltration Total RADTRAD Thyroid PERC2 1-131 Activity Released (Ci)

Org I

RADTRAD Results Comparison 1-131 Act.

RT/PERC2 RT/PERC2 Total Part Elem Total Total Thy Dose Actif CNT ESF MSL-W (100 Seth) 4.599E-05 1.095E-Oi Note l Note 1 3.254E+00 4.504E+01 1.095E-01 3.766E-02 4.830E+01 1.093E-01 3.88E-02 5.062E.01 3.095E+02 0.OOOE+Q0 2.633E.02 1.907E+03 4.629E+02 2.679E+03 1.290E+03 4.171E+04 4.300E+04 6.338E+02 2.680E4.01 9.239E.02 2.674E.03 4.303E.04 9.413E+02 0.997 0.974 1.048 0.998 1.001 1.019 Notes:

(1) Both the Intake and Infiltration contribution to the CR operator dose considered In a single PERC2 input file (2) 30 day Environmental Activity Release comparison.

(3) Successive reductions in RADTRAD's supplemental time step were taken until the results no longer appeared to depend on the choice of a time step value (-1/100"' of a second). This also had the benefit of providing good agreement between PERC2 and the RADTRAD results.

(4) PERC2 validation was run for Part 2 only. The dose results for Part 2, as would be expected, come much closer to the design dose limits discussed in the Acceptance Criteria section than the doses calculated in Part 1. Additionally, all of the modeling In Part 2 Is the same as Part 1 with the exception of an additional MSL line. PERC2 validation of the Part 2 RADTRAD transport models results In validation of Part I results.

I.E-FRM

NES-G-1 4.02 NES-G-1 4.02 Effective Date:

04DN4E00E lDESIGN ANALYSIS NO. DRE01-004D REV: 0 PAGE NO.42 I

8.0

SUMMARY

AND CONCLUSIONS The 'worst 2-hour period" dose at the EAB (4 hr to 6 hr period), the dose at the LPZ "for the duration of the release", and the 30 day CR dose, for the both the Base Case (Case 1) and the Proposed Design Basis Case (Case 2), is developed In-accordance with the guidance provided In RG 1.183. The calculated values represent the dose to the public and to the control room operator due to inhalation and submersion due to the radioactivity release following a LOCA at Dresden Power Station. Note that the dose estimates reported in the following Tables do not Include the direct shine contribution due to external sources. This source is usually considered to be insignificant (due to distance) for the site boundary locations, but should be addressed for the control room.

Tables 5 and 6 provide the estimated dose from each of the three release pathways, i.e., containment and ESF leakage via the SBGTS, and containment leakage via the MSIVs, for the Base case and the Proposed Design Basis Case, respectively.

Table 5 Part 1 "Base Case" EAB, LPZ and Control Room Doses (TEDE)

LOCA Location Dose (rem)

Reg. Limit (rem)

EAB (worst 2 hr period)

Containment Lkg via SBGTS 0.2 Containment 1kg via MSIVs 0.324 ESF Lkg via SBGTS 0.00 Total 0.6 25 LPZ Containment Lkg via SBGTS 0.07 Containment Lkg via MSIVs 0.1 ESF Lkg via SBGTS 2.OO2 Total 0.2 25 Control Room:

Containment Lkg via SBGTS 0.006 Containment Lkg via MSIVs 0.98 ESF Lkg via SBGTS Neg Total 1

5 I E-FORM

NES-G-14.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.43 Table 6 Part 2 "Proposed Design Basis" EAB, LPZ and Control Room Doses (TEDE)

LOCA Location EAB (worst 2 hr period)

Dose (rem)

Reg. Limit (rem)

Containment Lkg via SBGTS Containment Lkg via MSIVs ESF Lkg via SBGTS Total LPZ Containment Lkg via SBGTS Containment Lkg via MSIVs ESF Lkg via SBGTS Total Control Room:

Containment Lkg via SBGTS Containment Lkg via MSIVs ESF Lkg via SBGTS Total 02 1

1.342 1.3 25 0.08 0.25 0.08 0.4 25 0.004 4.519 Q001 4.53 5

I E-FORM I

NES-G-14.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.44 Conclusions The site boundary and control room inhalation I submersion dose following a LOCA at Dresden Power Station has been analyzed utilizing Alternative Source Terms and regulatory guidance as provided in RG 1.183. The dose consequences for the Base Case model and the Proposed Design Basis Case are reported in Tables S and 6 and remain within the acceptance criteria specified in I0CFR50.67 and Regulatory Guide 1.183.

The Base Case is intended to represent current design basis. The operational relief currently being investigated is modeled as the Proposed Design Basis Case. The model differences between the Base Case and the Proposed Design Basis Case is outlined in Table 1. The operational relief currently being investigated as the proposed design basis is presented below:

Increased allowable MSIV leakage from a total of 79.6 scfh @ 48 psig in all four lines to 100 scfh measured @ 48 psig in one line with a total of 250 scfh measured @ 48 psig in all 4 MSLs increased allowable control room inleakage from 263 cfm to 600 cfm (includes 10 cfm for ingress/egress) increased allowable containment leakage from 1.6% volume per day to 3%

volume per day reduced SBGTS charcoal iodine filter efficiency for organic and elemental iodine from 95% to 50%

increased credit taken for the SBGTS HEPA filter efficiency from 95% to 99%

reduced control room charcoal iodine filter efficiency for organic and elemental iodine from 99% to 95%.

increased allowable ESF leakage from 10 gph to 1 gpm It is noted that to demonstrate compliance with the control room regulatory limits, the estimated dose to the control room operator should include the contribution due to direct shine from contained sources / cloud shine. Sufficient margin appears to exist between the calculated control room operator dose resulting from inhalation and submersion for the proposed design basis case (i.e.; 4.53 Rem TEDE), and the regulatory limits (i.e.;

I E-FORM :A

NES-G-1 4.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.45 5 Rem TEDE), to allow the inclusion of the referenced direct shine contribution without exceeding the acceptance criteria Listed below are some of the assumptions utilized in this analysis which may require additional analytica~licensing defense from EXELON as part of the licensing submittal:

Current licensing basis of no reactor building bypass leakage Current licensing basis assumption that there is sufficient mixing in the reactor building to allow 50% mixing credit Current licensing basis that the X/Q values applicable for the control room intake is representative for control room inleakage.

MSIV/containment leak rate will reduce to half it value after 24 hrs.

I E-FORMW

NES-G-114.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.46 APPENDIX A MSL leakage Study for Dresden and Quad Cities MSL Leakage versus post-LOCA 30-day Control Room TEDE Dose Objective The purpose of this Appendix is to perform a sensitivity study of MSL leakage vs 30 day control room TEDE dose based on the limiting station utilizing the 5th unit concept. This study will be used by EXELON to establish the proposed design change relative to MSIV leakage at both Dresden and Quad Cities.

In the study, the total MSL leakage is the variable subject to the constraint that the MSL leakage contribution to the control room dose Is limited to approximately 4.5 Rem TEDE at the limiting station between Dresden and Quad Cities for a proposed control room inleakage of 600 cfm.

The two conditions of interest are:

Maximizing the total MSIV Leakage Maximum MSL leakage in a line specified as 100 scfh @ 48 psig for 24 hrs (then half the value for the duration of the accident) with the remaining leakage allocated to the worst configuration of the remaining lines.

Approach Computer program RADTRAD is used to calculate the control room operator dose versus MSL leakage using the activity transport model developed and described In Section 3 and presented in Figure 1 of the parent calculation. Two dose curves are generated, one for the "worst" line (i.e., assuming single failure of the outboard MSIV in the shortest line), and one for the most limiting line representative of the "remaining" lines (assuming a break immediately downstream of the outboard MSIV).

The principal assumptions of this study as per Reference 4 are that the:

the calculated control room operator dose at Dresden Station is more limiting than the control room dose at Quad Cities Cities (by inspection of the CR dispersion factor (xIQs) and CR volumes) and dose calculated at either stations site boundary EAB and LPZ.

maximum allowable leakage from any one line Is 100 scfh @ 48 psig.

AST Source Term for both Dresden and Quad Cities is the same.

I E-FORM I

NES-G-14.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.47 rate of aerosol and elemental iodine deposition in the drywell and in the main steam lines is the same for both Dresden and Quad Cities following a LOCA.

control room normal and emergency ventilation system design and operation is the same for both Dresden and Quad Cities and that total Infiltration for either plant is fixed at 600 cfm.

total drywell leakage for both Dresden and Quad Cities is fixed at 3 volume.

fractions per day.

The control room operator TEDE dose is calculated for the "worst line" assuming MSIV leakage rates of 100, 90, 80, 70, 60 and 50 scfh, and from the representative "remaining line" assuming MSIV leakage rates of 100, 90, 80, 60, 40 and 20 scfh.

RADTRAD Input leakage rates Single Leakage MS line leakage raters to void °2)

(scfh)

WM(cm)

WfM) 100 0.3907 2.9009 90 0.3517 2.94 80 0.3126 2.9791 70 0.2735 3.0181 60 0.2344 3.0572 50 0.1954 3.0963 40 0.1563 3.1354 20 0.07815 3.2135 Note: (1) After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> the leakage values are reduced by half.

(2) The control room dose due to activity that leaks Into the void (activities that would be released via other pathways) regions is not accounted for.

List of Computer Runs File Name Time and Date Stamp Run Description DRE Units 2 and 3 Part 2 'Base Case with Proposed Design Changes with Variable MSL Leakage Rates R0040dreA01a.out RADTRAD Version 3.02a run on 7/1812002 at B:40:54 core gap release -

Cont. Alm. e 100 scth

_Worst MSL 4 Environ (CR)

R004OdreADlb.out RADTRAD Version 3.02a run on 7/18/2002 at 9.06:51 E I-V release 4 Cont. Atm. 4 4 10 scfh Worst

_MSL 4 Environ (CR)

R0040dreAO2a.out RADTRAD Version 3.02a run on 7/18/2002 at 9:29 03 core gap release 4 Cont Alm. 4 90 scth Worst

___________M SL 4 Environ (CR)

R0040dreAO2b.out RADTRAD Version 3.02a run on 7/182002 at 9:44:48 E I-V release 4 Cont Alm. 4 90 sch Worst I

E-FORM I

NES-G-1 4.02 Effective Date:

04_14/00 DESIGN ANALYSIS NO. DRE01-0D40 REV: 0 PAGE NO.48 l~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

File Name Time and Date Stamp Run Descrip lon DRE Units 2 and 3 Part 2 B13ase Case with Proposed Design Changes with Variable MSL Leakage Rates MSL 4 Environ (CR)

R0040dreA03a.out RADTRAD Version 3.02a run on 711812002 at 10:43:14 core gap release 4 Cont. AM. 4 80 scch Worst MSL 4 Environ ICR)

R004OdreAo3b.out RADTRAD Version 3.02a run on 711812002 at 10:57:43 E INV release 4 Cont. Atm. 4 80 sc=h Worst MSL 4 Environ (CR)

R0040dreAO4a.out RADTRAD Version 3.02a run on 7/29J2002 at 17:21:25 core gap release 4 Cont. Atm. 4 70 sclh Worst MSL 4 Environ (CR)

R0040dreA04b.out RADTRAD Version 3.02a run on 7/1912002 at 8:45:38 E I-V release 4 Cont. Atm. 4 70 scfh Worst MSL 4 Environ (CR)

R0040dreAOSa.out RADTRAD Version 3.02a run on 711912002 at 9:12:24 core gap release 4 Cont. Atm. 4 60 sclh Worst

-MSL 4 Environ (CR)

R0OWOdreA05b.out RADTRAD Version 3.02a run on 7/1192002 at 9:58:02 E IV release 4 Cont. Atm. 4 60 sclh Worst MSL 4 Environ (CR)

R0040dreA06a.out RADTRAD version 3.02a run on 711912002 at 11:10:30 core gap release 4 Cmnt. Alin. 4 50 sclh Worst MSL 4 Environ (CRl RO040dreAO6b.out RADTRAD Version 3.02a run on 7/1912002 at 11:27:13 E INV release 4 Cont. Alm. 4 50 scrn Worst MSL 4 Environ (CR)

R0040dreA07a.out RADTRAD Version 3.02a run on 7/1912002 at 11:43:13 core gap release 4 Cont. Atm. 4 100 sclh Worst MSL 4 Environ (CR)

R0040dreAO7b.out RADTRAD Version 3.02a run on 711912002 at 11:57:53 E I-V release 4 Cont Atm. 4 4 100 scWm Worst MSL 4 Environ MCR)

R0040dreA08a~out RADTRAD Version 3.02a run on 7/25/2002 at 18:06:47 core gap release 4 Cont Ahm. 4 90 sclh Worst MSL 4 Environ (CR)

R0040dreAO~b.out RADTRAD Version 3.02a run on 7/1912002 at 12:50:54 E I-V release 4 Cont. Atm. 4 90 scfh Worst MSL 4 Environ (CR)

R0040dreAO9a.out RADTRAD Version 3.02a run on 7/1912002 at 13:19:26 core gap release 4 Cont. Atm. 4 80 scfci Worst MSL 4 Environ (CR)

R0040dreAO9b.out RADTRAD Version 3.02a run on 7/1912002 at 13:35:49 E WV release 4 Cont. Atm. 480 sclh Worst MSL 4 Environ (CR)

R0040dreAlOa.out RADTRAD Version 3.02a run on 7/192002 at 14:01:33 core gap release 4 Cont Atm. 4 60 sclh Worst MSL 4 Environ (CR)

R0040dreAlOb.out RADTRAD Version 3.02a run on 7/19/2002 at 14:17:38 E l-V release 4 Cont. Atm. 4 60 sclh Worst MSL 4 Environ (CR)

R0040dreAl la.out RADTRAD Version 3.02a run on 7/19/2002 at 14:41:06 core gap release 4 Cont. Atm. 4 40 scfh Worst MSL 4 Environ (CR)

R0040dreAllb.out RADTRAD Version 3.02a run on 7119f2002 at 15:20:10 E l-release 4 Cont. Atm. 4 40 scci Worst MSL 4 Environ (CR)

RO040dreAl2a.out RADTRAD Version 3.02a run on 7122/2002 at 9:01:49 core gap release 4 Cont Atm. 420 fsdh Worst MSL 4 Environ (CR)

R0040dreAl2b.out RADTRAD Version 3.02a run on 7/2212002 at 9:37:40 E I-V release 4 Cont. Atm. 4 20 scfh Worst IMSL 4 Environ (CR)

,ORM I

NES-G-14.02 Effective Date:

04/14/00 DESIGN ANALYSIS NO. DRE01-004 REV: 0 PAGE No. 49_

Results CR TEDE Dose from "worst" and "remaining" MS line Worst MS Dose from Dose from Single MS Dose from Dose from Une Lkg.

gap Rel.

EIV Rel.

TEDE RL Lkg.

gap Rel.

EIV Rel.

TEDE (scfh)

(rem)

(rem)

(rem)

(scfh)

(rem)

(rem)

(rem) 100 0.35856 2.47490 2.83346 90 0.26852 1.83590 2.10442 80 0.19459 1.31430 1.50889 70 0.13596 0.90385 1.03981 60 0.09126 0.59425 0.68551 50 0.05848 0.37085 0.42933 100 0.18518 1.22130 1.40648 90 0.14255 0.92691 1.06946 80 0.10753 0.68778 0.79531 60 0.05710 0.35106 0.40816 40 0.02633 0.15471 0.18104 20 0.00822 0.04631 0.05453 Adding a (0,0) point to thetworst" and "remaining" MS lines results, the results were then curvefitted and plotted in Figures Al and A2. Examination of the input data and the shape of the resulting curves provided insight into selecting the worst configurations for dose consequence analyses. The highest consequence always resulted from the case where the maximum allowable line flow was used with any remainder being allocated to the last line. For example, In maximizing the dose for a MSIV total leakage of 280 scfh @ 48 psig with a maximum allowable leakage of 100 scfh e 48 psig, the highest dose resulted from the selection of the 'Worst" line being at a 100 scfh @

48 psig and the "remaining" lines being at 100 scfh @ 48 psig and 80 scfh @ 48 psig rather than the Oremaining" lines being 2 - 90 scfh e 48 psig or 3 - 60 scfh @ 48 psig configurations or another flow combination. This insight provides simplification in the later analysis where MSIV leakage flows are combined to calculate a MSIV Leakage isodose curve for the control room.

The curvefits in Figures Al and A2 resulted in 5t order polynomial expressions with the following coefficients:

E-FORM I

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.50 YV a~xA5+b~xA4+exl%3.d~xA2+eWx+f a

b C

d e

f Worst Line

-1.42363446836328E-10 3.35512798367489E-08 1.9545571 3990609E-08 7.18060834270149E-05 1.64353990933016E-03

-4.87066944643041 E-08 Remaining line

-6.87005376270971 E-1 1 2.17755715056959E-08

-1.33008461944934E-06 1.17061334651 532E-04 7.54012651713977E-04 2.20814405364869E-07 A comparison of fit was then made to ensure that the derived expression adequately represented the data.

As demonstrated below, the curvefit closely reproduced the Inputted data.

"Worst" Line Flow Input Calc.

"Remalning" Line Flow Input Calc.

(scfh 0 48 psig) 0 50 60 70 80 90 100 Dose (rem) 0 0.42933 0.68551 1.03981 1.50889 2.10442 2.83346 Dose (rem)

-4.87E-08 OA29342 0.685459 1.039898 1.508813 2.104454 2.833454 Difference (Rem) 4.87E-08

-1.23E-05 5.11 E-05

-8.77E-05 7.67E-05

-3.41 E-05 6.14E-06 (scfh 0 48 pslg) 0 20 40 60 80 90 100 Dose (rem) 0 0.05453 0.18104 0.40816 0.79531 1.06946 1.40648 Dose (rem) 2.21 E-07 0.054529 0.181044 0.408153 0.79532 1.069452 1.406482 Difference (Rem)

-2.21 E-07 1.42E-06

-3.97E-06 6.62E-06

-9.94E-06 8.08E-06

-1.99E-06 From the curvefits and the RADTRAD results, it was possible to derive a control room MSIV leakage isodose curve. Selecting a control room dose of 4.5 Rem due to MSIV Leakage, the following MSIV leakage combinations were derived.

E-FORM I

NES-G-1 4.02 Effective Date:

04/14100 3O5 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 Une Maximum Flow per LIne (sch @ 48 psig) 100 99 97.5 95 92.5 92 91.97891 91.975 91.3 91 90.5 90 88.75 87.5 86.25 85 84.53962 1

"'Worst" Line Flow -

sch 0 48 pslg (Dose - Rem) 100 (2.83346) 99 (2.75451) 97.5 (2.63860) 95 (2.45214) 92.5 (2.27409) 92 (223949) 91.97891 (2.23804) 91.975 (2.23777) 91.3 (2.19162) 91 (2.17130) 90.5 (2.13771) 90.5 (2.10442) 88.75 (2.02278) 87.5 (1.94319) 86.25 (1.86568) 85 (1.79023) 84.53962 (1.76296) 2

'Remaining" LUne # 1 Flow -

scfh @ 48 pslg (Dose - Rem) 100 (1.40648) 99 (1.36980) 97.5 (1.31604) 95 (1.22977) 92.5 (1.14760) 92 (1.13165) 91.97891 (1.13098) 91.975 (1.13086) 91.3 (1.10959) 91 (1.10023) 90.5 (1.08476) 90.5 (1.06946) 88.75 (1.03186) 87.5 (0.99525) 86.25 (0.95959) 85 (0.92489) 84.53962 (0.91235) 3 "Remaining" Line # 2 Flow -

safh @ 48 psig (Dose - Rem) 48.297 (0.260061) 57.738 (0.375690) 68.289 (0.545358) 80.920 (0.818094) 90.290 (1.07831) 91.912 (1.12886) 91.97891 (1.13098) 91.975 (1.13086) 91.3 (1.10959) 91 (1.10023) 90.5 (1.08476) 90.5 (1.06946) 88.75 (1.03186) 87.5 (0.99525) 86.25 (0.95959) 85 (0.92489) 84.53962 (0.91235) 4 "Remaining" UIne # 3 Flow -

scfh 0 48 pslg (Dose - Rem) 0 0

0 0

0 0

0 0.625 (5.171 17E-04) 26.841 (8.9201 9E.02) 33.078 (1.28233E-01) 41.363 (1.92764E-01) 47.979 (2.56668E-01) 60.359 (4.13497E-01) 69.412 (5.6631 7E-01) 76.592 (7.151 36E-01) 82566 (8.59990E-01) 84.53962 (9.1 2348E-01)

Maximum MSIV Leakage Allowable (scfh 0 48 psig) 248.297 255.738 263.290 270.921 275.290 275.912 275.937 276.550 300.741 306.078 312.863 317.979 326.609 331.912 335.342 337.566 338.158 l[

E-FORM l

NES-G-1 4.02 Effective Date:

04/14100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO. 52 Plotting these results yielded isodose curves for 3 and 4 MSIV Lines leaking and the combination curve (Figures A3 - A5). Using this methodology and the curves derived for Figures Al & A2, other isodose curves for the MSIV Leakage contribution to control room dose follow a LOCA can be derived.

E-FORM i

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE Figure Al Control Room Dose Due to MSIV Leakage (Worst Line) 3.0 w

0)

~20 pCC,1.5 U)

No 1.0 0

a 0

C)0.

0.0 d-0.0 10.0 20.0 30.0 40.0 60.0 70.0 80.0 90.0 MSIV Leakage Rate for Worst Line (scfn @ 48 psig)

I E-FORM lI

NES-G-114.02 Effective Date:

0411410 DESIGN ANALYSIS NO. DREOI-0040 REV: 10

-PAGE NO.,54

-- I Figure A2 Control Room Dose Due to MSIV Leakage (Representative Une) w (X

S an M

.5' aC

.r a

U 0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0 80.0 MSIV Leakage Rate for Representative Line (scfn @ 48 psig) 100.0 I

E-FORM I

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREO1-0040 REV: 0 PAGE NO.55 Figure A3 280.0 275.0 a

0 a:

0

£0 0I-270.0 265.0 Maximum MSIV Leakage per Llnevs. Total MSIV Leakage for 3 Lines Radtrad Control Room AST Doses Due to MSIV Leakage X 4.5 Rem X

1.

.cIi.,,

I

I

• .e.i,. I em ii a

m

,Il'l' 260.0 255.0 250.0 245.0 9,1.0 92.0 93.0 94.0 95.0 96.0 97.0 98.0 99.0 100.0 MSIV Maximum Leakage Rate per Line (scdh 0 48 psig)

I E-FORM

NES-G-1 4.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DREOI-0040 REV: 0 PAGE NO. 56 Figure A4 Maximum MSIV Leakage per Linevs. Total MSIV Leakage for 4 Lines 340.0 330.0 0,a.

c 320.0 0

is U

-S 310.0 2U S

.X 300.0 w

0 E 290.0 a1 I-280.0 270.0 L" 84.0 85.0 86.0 87.0 88.0 89.0 90.0 91.0 92.0 MSIV Maximum Leakage Rate per Line (scah 0 48 psig)

II E-FORM II

NES-G-14.02 Effective Date:

04114100 DESIGN ANALYSIS NO. DRE01-0040 REV: 0 PAGE NO.57 Figure A5 Total MSIV Leakage vs. Maximum Leakage per Line Control Room Dose Constant at 4.5 Rem 0.

la 0

0 9-340 -

330 -

320 -

310-300-290-280 -

270 -

260-250-240 84 86 88 90 92 94 96 Maximum Leakage per Line (scfh @ 48 pslg) 98 100 E-FORM J

NES-G-1 4.02 Effective Date:

04/14/00 REV: 0 PAGE NO.68 IDESIGN ANALYSIS NO. DREO1-0040 LIST OF ATTACHMENTS Attachment A Attachment B TODI ER2002-9994, Rev 1 Including Attachment 1 CD ROM of Computer Output Final Page Page 58 of 58 I

E-FORM

.C...a4h. 'DEOI-Oca~a ivJ 0 F51 3

EXELON TRANSMITTAL OF DESIGN INFORMATION X SAFETY-RELATED Originating Organization TODI No. ER2002-9994 rev. I

_NON-SAFETY-RELATED X Exelon

REGULATORY RELATED

-Other (specify)

Station Dresden Unit(s) 2(3)

Page 1

of 2

System Designation:

(0000)

To S. Fersuson - Stone and Webster

Subject:

Dresden Station Concurrence with the Design Inputs as established for Alternate Source Term (AST) LOCA Analysis.

D. Oaklev y Ma 7-3I-oa Preparer Preparees Signature Date M. Molaei

____7__

/3_ jz Approver Approver's Signature Date Status of Information:

X Approved for Use Unverified Method and Schedule of Verification for Unverified TODIs: NI/A Description of Information:

Transmit Dresden Station concurrence with the revised design inputs for the AST LOCA Analysis. These inputs were derived based upon the combined efforts of Quad Cities Station, Dresden Station, and Corporate Engineering Subject Matter Expert. The attachment contains a finalized list of these design inputs. Information was retrieved from controlled sources as listed in the attachment.

Purpose of Issuance:

Transmit a finalized revised list of design inputs Limitations:

None Source Documents: Various - The referenced source documents have been listed with each value in the attachment.

Distribution: D. Galanis, G. Lahti R.Ruffin, M. Uhbrch.} R L? I PI

C-PA-C Zb 9,Z ol I -

1
). Iraq 0 V t 2 j 2.3 PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SOURCE TERMS Item Leference Value Comments

1. Reactor Core Power Level GENE A22-00103-01 3016 MWt Includes 2% margin for conservatism 01, Rev.0 iaw RG 1.49, Rev 1; i.e., 2957 MWt 1.02 = 3016 MWt Reg. Guide 1.183, Rev 0

2. Design Basis Core Activity (Curies)

GENE-A22 00103 Values in Appendix D of Isotopes utilized in the analysis will be 01, Rev.0 Reference (Ci/MWQ) times 3016 limited to the 60 isotopes that form the MWt. Values used are those with standard librarytinput in Computer Code 1600 EFPD burnup RADTRAD. The referenced computer code is NRC sponsored and is intended for use in AST applications.

TODI ER2002-9994 Rev 1 Attachment 1 Page I of 22

(:Njj
D

(

0 (+f,), ?\\1Cj f% 2 j 7Z PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCQA - ALTERNATIVE SOURCE TES Irem Reference

_'ahie Comments

3. Activity Release Paths ContainmentLeakag&

Per reference, current plant design does ComEd letter to NRC, not allow bypass of the SBGTS.

"Revised Control Room Release from fuel to drywell; Building release Roints:

Radiological leaked to reactor building; released Assessment", May 19, to environ via SBGTS Containment Leakage via SBGTS -

1997 Elevated Chimney MSIV Leakage MSIV Leakage - steam line tunnel Design info Transmittal ESF Leakage via SBGTS - Elevated Doe ID No. CC200I-Release from fuel to drywell; Chimne 9994,4/13/01 leaked to the environ via MSIV's ESFLeakate Release from fuel to suppression pool; released to reactor building due to equipment leakage; released to environ via SBGTS Containment Purge Release, to Relieve Pressure or to Reduce HMdrogen Concentration None TODI ER2002-9994 Rev I Attachment I Page 2 of 22

CA~L ON DQs01-;w~t'j r Aj t-V t 7-3 PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SOURCE TERMS Item Ref0'nce Value Comments

4. Elements in each Radionuclide Group released Reg. Guide 1.183, Rev 0 Noble gases: Xe, Kr Note: RADTRAD default libraries into Containment following a LOCA Halogens 1, Br contain a maximum of 60 isotopes with associated nuclear data libraries Alkali Metals: Cs, Rb Tellurium Grp: Te, Sb, Se Ba, Sr: Ba, Sr Noble Metals: Ru, Rh, Pd, Mo, Tc, Co Cerium Grp: Ce, Pu, Np Lanthanides : La, Zr, Nd, Eu, Nb, Pm, Pr, Sm, Y, Cm, Am

5. Core Inventory Fraction Release into the Reg. Guide 1.183, Rev 0 Noble gases: 0.05 All fission products released from the Drywell Atmosphere of each Radionuclide group Halogens

• 0.05 fuel are instantaneously and during Gap Release Phase homogeneously mixed in the Drywell Alkali Metals: 0.05 atmosphere at the time of release from the core.

LCO The peak bumup of GE14 fuel is Note that these release fractions are DPR-30 3.T limited to 62,000 MWD/MTU.

based on LWR fuel with a peak burnup DCR-29 3.U up to 62,000 MWD/MTU.

TODI ER2002-9994 Rev I Attachment 1 Page 3 of 22

C4'L -h- "z 9,G GI -

0 a 4r.3, t.Aj i
l its.I ?z PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SOURCE TERMS item Refence VaeCmmn

6. Core Inventory Fraction Release into the Reg. Guide 1.183, Rev 0 Noble gases: 0.95 All fission products released from the Drywell Atmosphere of each Radionuclide group Halogens: 025 fuel are instantaneously and during Early In-Vessel Release Phase homogeneously mixed in the drywell Alkali Metals: 0.20 atmosphere at the time of release from Tellurium Grp: 0.05 the core Ba, Sr: 0.02 Note that these release fractions are Noble Metas:

0.0025based on LWR fuel with a peak burnup Noble Metals: 0.0025 up to 62,000 MWD/MTU.

Cerium Grp: 0.0005 Lanthanides: 0.0002 LCO The peak bumup of GE14 fuel is DPR-30 3.T limited to 62,000 MWD/MTU DCR-29 3.U

7. Core Inventory Fraction Release into the Reg. Guide 1.183, Rev 0 Noble gases: 0.00 With the exception of noble gases, all suppression pool of each Radionuclide group Halogens: 0.05 fission products released from the fuel during Gap Release Phase are instantaneously and homogeneously Alkali Metals: 0.05 mixed in the suppression pool at the time of release from the core.

TODI ER2002-9994 Rev I Attachment I Page 4 of 22

Q.s&l A

m-oC\\b jA'Jk~ Z

% (

53 PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SOURCE TERMS item Reence Klerue Comments

8. Core Inventory Fraction Release into the Reg. Guide 1.183, Rev 0 Noble gases: 0.00 With the exception of noble gases, all suppression pool of each Radionuclide group Halogens: 0.25 fission products released from the fuel during Early In-Vessel Release Phase are instantaneously and homogeneously Alkali Metals: 0.20 mixed in the suppression pool at the time Tellurium Grp: 0.05 of release from the core.

Ba, Sr: 0.02 Noble Metals: 0.0025 Cerium Grp: 0.0005 Lanthanides :0.0002

9. Core Inventory Release Timing - Gap Release Reg. Guide 1.183, Rev 0 Onset:

2 min Phase Duration: 0.5 hrs

10. Core Inventory Release Timing - Early In-Reg. Guide 1.183, Rev 0 Onset: 0.5 hrs after onset of Gap Vessel Release Phase Duration: 1.5 hrs I 1. Iodine Form of activity released to drywell Reg. Guide 1.183, Rev 0 4.85% Elemental atmosphere from melted and failed fuel 95% Particulate 0.15% Organic TODI ER2002-9994 Rev 1 Attachment I Page 5of 22

CK--

ark'\\

- ortm 3 k4 0

?
+i 12 PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION item Refrence Value Comments

12. Suppression Pool Scrubbing Credit Reg. Guide 1.183, RO Not Credited Per RG 1.183, suppression pool scrubbing is generally not credited. Due to the delay in release of the fission products, it can no longer be assumed that the fission products will be immediately directed to the suppression pool as part of the initial pressure transient. For Mark I BWRs, it is expected that most of the fuel release will remain in the drywell and leak directly out into the reactor building without suppression pool scrubbing.

Portions of the fuel release may be scrubbed, but a technical defense has to be provided based on mass flow rate into suppression pool vs time, pool temperature vs time, venting depth, etc.

Therefore, the analysis cannot use a DF of 5 as suggested in SRP6.5.5.tl1.1 and used in Calc DRE97-0130, RO. For purposes of this analysis no credit will be taken for suppression pool scrubbing.

TODI ER2002-9994 Rev I Attachment I Page 6of 22

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PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SURCm TERMS 11cm

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13. Elemental iodine deposition/plateout removal coefficients in Containment based on:

Surface area in drywell Drywell Free volume R.G 1.183 OPL-4A, transmitted by TODI DGOO-000830, 7/11/00 & Design Info Transmittal No.

CC2001-9994, 4/13/01.

NUC-1, Rev 2 RADTRAD requires user specified removal lambdas. Per RG 1.1 83, the iodine removal coefficients will be-calculated using SRP 6.5.2, Rev 2 methodology. Torus area / volume is not considered.

Drywell surfaces are assumed to be wetted during the early stages of the event during which credit is taken for elemental iodine removal. Per RG 1.1 83, credit for elemental iodine removal is taken until a DF of 200 is reached.

Per OPL-4A, the listed surface area is that associated with the steel area of the drywell shell surface and the LOCA vent pipes.

Surface area: 32,250 sq ft Drywell Volume: 1.58E5 cu ft I

I TODI ER2002-9994 Rev 1 Attachment 1 Page 7 of 22

PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALT-R-N-AT-IVE SOURCE TEM S-item Valve Comments

14. Particulate aerosols deposition/plateout RG 1.183, RO To be calculated by S&W using Per RG 1.183, the 10% percentile (most removal in Containment based on:

NUREG/CR-6189 equations for the Power's model in conservative) values will be used for the NUREG/CR-6189 and input evaluation.

directly into RADTRAD as natural deposition time dependent lambdas

15. Credit for fission product removal by sprays N/A None

16. Long Term Suppression Pool pH (taking into pH of 7

. Credit will be taken for sodium consideration acid production due to radiolysis To be confirmed by pentaborate in the Standby Liquid and cable degradation).

S&W in a separate Control System. This system will be analysis activated manually via the EOP's.

TODI ER2002-9994 Rev I Attachment I Page 8 of 22

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~

~

~

~

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~ j.~e~~n~e" The following value is obtained from l17a, MSL Leak Rate: Base Case llCast I "Base Case"ls:'

R9703, e.

Calc. DRE97-0130, Rev.0 46 scfl for four MSLs @ 25 Tech. Spec 3.6.1.3 psig (test pressure)

• 79.6 scfh @ design pressure for 4 SR 3.6.1.3.10.

MSLs, i.e. 0.0016 volume fractions per day based on a containment volume that includes drywell and DRE97-0130, Rev.0 79.6 scfh @ 48 psig total from torus)

DRE-97-0078, R3 all four ( 4) MSLs Note that per DRE-97-0078, R3, the conversion factor to address leakage at Analysis will assume 100%

containment design pressure from tested leakage for the duration of the pressure is 1.73.

event from one (I) MSL It is recognized that under EPU conditions the revised value for drywell accident pressure is 43.9 psig. The Pre-EPU value of 48 psig was used as a reference point during the performance of this analysis. The delta in accident pressure should be discussed in the design input of the calculation.

Asumed Case 2 "ProLosed Case" Note that per DRE-97-0078, R3, the TODI ER2002-9994 Rev I Attachment I Page 9 of 22

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Comments 17b. MSL Leak Rate: Proposed Case Exelon to select MSIV leakage parameters based on study described below Study Details Total MSL leakage is a variable subject to the constraint that the MSL Leakage total contribution to CR Dose is limited to approximately 4.5 Rem at the limiting station between Dresden and Quad Cities for a proposed CR inleakage of 600 sefin.

There are two (2) conditions of interest:

Maximizing total MSIV Leakage Worst MSL leakage specified as 100 scfh @ 48 psig for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (then half value for the duration of the accident) with the remaining leakage allocated to the worst configuration of the remaining lines.

conversion factor to address leakage at containment design pressure from tested pressure of 25 psig to design pressure of 48 psig is 1.73.

Per RG 1.183, the MSL leakage may be reduced to a value not less than SO% at T= 24 hrs if supported by plant analyses.

Exelon is aware that plant specific analysis may be needed to support the utilization of this assumption.

Graphs depicting MSL Flow vs CR Dose Contribution for the Worst Line and the Representative Line provided for a proposed CR inleakage of 600 scfm are generated as a result of the 2 study conditions. Based on review of the graphs Exelon will select the allowable MSL leak rate for the Proposed Case.

It is recognized that under EPU conditions the revised value for drywell accident pressure is 43.9 psig. The Pre-EPU value of 48 psig was used as a reference point during the performance of this analysis. The delta in accident pressure should be discussed in the design input of the calculation.

TODI ER2002-9994 Rev I Attachment I Page IO of 22

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-23 PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTEORNATIVE SOUERCE TEM Item Rence Value Comments 1 8a. Leakage Rate from Containment: Blase Case Case 1 "Base Case" All leakage estimates provided in "volume fractions per day" are based on Tech. Spec. B 3.6.1.2 Total Containment leakage - 0.016 drywell volume only per guidance in RG volume fractions per day at design 1.183 pressure of 48 psig:

Note that the volume fractions released DRE97-0130, Rev 0

• Leakage through MSL -

via the MSLs and reactor building used 0.00283 volume fractions per in DRE97-0130, Rev 0 are 0.0016 (see day at 48 psig item 17a for basis of MSL leakrate in volume fractions per day) and 0.0144 Leakage into reactor building -

respectively. Since per RG 1.183, the 0.01317 volume fractions perg AST methodology assumes that the day0(ie..0117 6volum 3 fractis pr activity release occurs only in the day (i.e. 0.016.0.00283) at 48 Drywell volume, (whereas, DRE97-psig 0130, which is based on TID methodology takes credit for dilution in "Base Case" analysis will assume the whole containment), the volume 100% leakage for the duration of fractions are adjusted to reflect the the event.

volume adjustment. The containment volume is 2.78E5 cu ft whereas the drywell volume is 1.58E5 cu ft.

TODI ER2002-9994 Rev I Attachment I Page I I of 22

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-TERNATIVE SOUR TEMS tem Refrence Vole COmmentS Assumed Case 2 oosed Case" See Item 17b for basis of MSL leakage 1 8b. Leakage Rate from Containment: Proposed i

ouefatosprdy Case

~~~~~~~~~~~~~~~~~~~~~~~~~~~in volume fractions per day.

Case Total leakage - 0.03 volume fractions per day at 48 psig.

All leakage estimates provided in "volume fractions per day" are based on leakage is reduced to 50% at T=24 drywell volume per guidance in RG hours 1.183 Per RG 1.1 83, the containment leakage Containment leakage determined as may be reduced to a value not less then the difference between total leakage 50% at T-24 hrs if supported by plant and the maximum MSL leakage analyses. Exelon is aware that plant determined from the 2 study specific analysis may be needed to conditions identified in item 17b support the utilization of this assumption.

19. Primary Containment Free Volume

• Drywell plus Suppression Chamber Free Air

• DRE97-0130, Rev 0

• 2.78E+05 f 3 Volume Drywell only NUC-1, Rev 2 1.581+05 e TODI ER2002-9994 Rev I Attachment I Page 12 of 22

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20. Reactor Building Drawdown Time following a OPL4A (PDLB Current Design Basis: No delay; The design of the reactor building and LOCA (prior to be being exhausted via SBGTS)

Version), 8/1/00 Drawdown time is zero the SBGT System is to maintain the taking into consideration loss of power and worst reactor building at slight negative case single failure. (i.e., time period after LOCA UFSAR 6.2.3.3 pressure under normal and accident before the Reactor building will achieve -0.25 in conditions. This precludes exfiltration wg)

Design information from the building. During previous Transmittal ID#

secondary containment leak rate CC2001-9994, 4/13/01 surveillance, it has been observed that the reactor building pressure is maintained substantially negative (>0.2 in wc vacuum)

21. Standby Gas Treatment System Flow DRE97-0130, Rev 0 4000 cfm n 10%/o Per DRE97-0130, Rev 0, the SGTS is safety related and with this flow can maintain the reactor building at -0.25 inch w.g. pressure;

22. Reactor Building Free Volume 4.5E+06 fe DRE97-0130, Rev.0 TODI ER2002-9994 Rev I Attachment 1 Page 13 of 22

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23. Fraction of Reactor Building Volume Available for Mixing DRE97-0130, Rev.0 0.5 50% is the maximum allowed by RG 1.183.

Cale. DRE97-0130 states that the SBGTS configuration shows that the containment leakage can not "short circuit" to the release point.

Exelon recognizes that this assumption may need some additional defense in the form of an analysis.

24. Fraction I duration of containment leakage that DRE97-0130, Rev.0 Need not be analyzed Per Parameter Item 3, current plant bypasses the reactor building SGTS due to high design does not allow bypass of SGTS winds.

Per DRE97-0130, R0, previous analyses done for Dresden Station have indicated that doses developed using calm weather conditions are higher than doses calculated using high wind conditions and associated bypass leakage.

TODI ER2002-9994 Rev I Attachment 1 Page 14 of 22

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116 j 7Z PARAMETER LIST FOR OFFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SOURCE TERMS iem Reference Value Comments 25a. SBGTS Filter Efficiency: Base Case DRE97-O130, Rev.0 Case 1 "Base Case" HEPA:

Particulate aerosol: 95%

Charcoal Filter:

Elemental iodine: 95%

Organic Iodine: 95%

25b. SBGTS Filter Effliciency: Proposed Case Assumed Case 2 "Pronosed Valuel HEPA:

Particulate aerosol: 99%

Charcoal Fijlr:

Elemental iodine: 50%

Organic iodine: 50%

TODI ER2002-9994 Rev 1 Attachment I Page 15 of 22

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26. MSIV Leakage Deposition and Holdup Credit.

Reg. Guide 1.183:

To be developed by S&W Since holdup is allowed only in system To be developed based on the following input:

that can stand SSE, deposition / plateout will be credited only in piping upstream

• Data on MSLs

• DRE01-0001, Rev

• As per Reference of outboard MSIVs

- Internal surface of shortest MS line from O, DREOI-0002, reactor vessel nozzle to outboard MSIV (i.e.

Rev 0 Since vapor deposition is reduced at the seismic portion) higher temperatures, the temperature in

-Volume of above piping the MSLs will be assumed to be the

- Number of bends (including degree of bends) higher of that predicted for the MSLs vs drywell.

• Post LOCA containment pressure vs time for

• Figure 3-8 EPU

• GE-NE-A22-00103-Pressure in MSL will be assumed to be 08-01, Rev I same as in-containment pressure.

• Post LOCA containment temperature vs time

• Figure I for EPU

• GE letter GE-DQC-Post LOCA containment temperature &

EPU-386/DRF A22-pressure data beyond the times identified 000103-00, Nov in the figures will be conservatively 20,2000 assumed to remain unchanged after the

• MS Pipe temperature vs. time

• To be developed by S&W last recorded time noted in the figures

• SAIC Report by JECline, August 20, Post LOCA temperatures in the MS pipe 1990.

will be developed using SAIC report,

• MS line Flow: max. MSIV leakage in 1 line

• As noted below "MSIV Leakage for iodine Transport Case I Base Case

• As noted below 79.6 scfh @48 psig (Case 1)

Analyses", JECline, August 20, 1990, Case 2 Proposed Case DER97-0130, RO TBD schb @48 psig from study NRC Contract NRC-03-87-029, Task 75 Assumed conditions identified in item 17b (Case 2)

TODI ER2002-9994 Rev 1 Attachment I Page 16 of 22

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27. Suppression Pool liquid Volume used to DRE97-0130, Rev.0 I 10,000 ft3 assess ESF leakage 28a. ESF Leakage Rate: Base Case Case Per Cale. DRE97-0130, Rev.1, based on DRE97-0130, Rev.0 20 gal/ hr twice the typical industry leak rate of 10 gph.

28b. ESF Leakage Rate: Proposed Case Assumed Case 2 Typical Industry Value is I gpm.

Assessment uses 2 x allowable per RG 2 gpm 1.183

29. Fraction of ESF leakage that becomes airborne DRE97-0130, Rev.0 Iodine - 0.1 Calc. DRE97-0130 refers to USFAR that Particulates - retained in the liquid the Pool Condensation Stability Limit is phase 204 'F (< 212 'F.). Per RG 1.183, if temperature of fluid is less than 212 ° F, fraction airborne can be assumed to be 0.1 TODI ER2002-9994 Rev I Attachment I Page 17 of 22

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30. Iodine Form of Activity Released from ESF Reg. Guide 1.183, Rev 0 97% Elemental leakage to the Environment 3% organic 3.Duration of ESF leakage os ti 30 days Assumption

32. Fraction of Reactor Building Volume available for mixing for ESF leakage DRE97-0130, Rev.0 0.5 50% is the maximum allowed by RG 1.183.

Exelon recognizes that this assumption may need some additional defense in the form of an analysis.

33. Percentage of ESF leakage that is filtered DRE97-0130, Rev.0 100%

No leakage is assumed to bypass the filters in Caic. DRE97-0130.

34. Control Room Pressure Boundary Envelope Free Volume DRE97-0130, Rev.0 8o1,000 f Used in Calo. DRE97-0130, Rev.0. The above calculation uses the referenced volume to develop concentrations, but uses a smaller volume (64,000 cu ft) to establish whole body doses. However, currently, no data is provided on CR internal structures (such as wall thickness) that support the acceptability of the reduced finite volume model.

TODI ER2002-9994 Rev 1 Attachment 1 Page 18 of 22

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ft'2. Oj2.3 PARAMETER LIST FOR OFSITE AND CONTROL ROOM DOSE ANALYSIS - DRESDEN POWER STATION LOCA - ALTERNATIVE SOURCE TERHS hem Reference Volue Comments Per Calc. DRE97-0130, Rcv.0, Dresden

35. CR Ventilation System Design DRE97*0130, Rev.0 Pressurization (1/8" w.g.)

CR is pressurized to 1/8" w.g. during normal operation as well as during accidents

36. Control Room Ventilation Intake Design Per Calc. DRE97-0130, Rev.0, Dresden DRE97-0130, Rev.0 Single Intake has a single CR intake which is the same for both normal and emergency mode.

37. Control Room Intake/ Inleakage Atmospheric Calc. DREO1-0007, SBGTS Stack Dispersion Factors Rev.0 0-.

r 41E4sr 3 The SB3GTS Stack release considers an Dispersion Factors.0-0.5 hr 4.17E4 smlevated release with fumigation for the 0.5-2 hr 1.4 1E-8 s/rn3 first 0.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and non-fumigation for the 2-8 hr 5.57;-9 s/rn3 remainder of the accident 8-24 hr 3.50E-9 sW MSIV leakage is assumed to occur from 1-4 day 1.28&9 s m'

the edge of the MSIV rooms. MSIV 4-30 day 3.01 E-10 s/rn3 leakage XIQ values are based on the more limiting for the two Units, i.e., Unit 2 MSIV leakage.

0-2 hr 1 24e3 s/r3 The X/Q for Control Room Intake is 2-8 hr I

.08E-3 s/rn3 representative for Control Room 2-8 hr 1.0813-3 Sims/

Inleakage. Exelon recognizes that the 8.24 hr 5.29E-4 s/rn3 basis for this position may need to be 1-4 day 3.43E-4 s/rn' documented.

4-30 day 2.72E-4 s/m' TODI ER2002-9994 Rev 1 Attachment 1 Page 19 of 22

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38. Control Room Breathing Rate RADTRAD Default 0-30 day - 3.47E-4 m' Is Value

39. Control Room Occupancy Factors RADTRAD Default 0-24 hrs - 1.0 Values 1-4 days - 0.6 4-30 days - 0.4

40. Control Room Emergency Ventilation DRE97 0130, Rev.0 T=40 Minutes by manual operation.

Filtration System Actuation Time following a During the first 40 mins the CR is LOCA assumed to be on normal ventilation

41. Normal unfiltered ventilation air intake into DRE97-0130, Rev.0 2,000 cfm i 10 %

Used in DRE97-0130, Rev.0.

the CR

42. CR emergency ventilation air Intake Rate DRE97-0130, Rev.0 2,000 cfin 10 %

43a. CR emergency ventilation intake filter DRE97-0130, Rev.0 Case 1 Used in Calc. DRE97-0130, Rev.0 efficiency: Base Case Charcoal Elemental iodine: 99%

Organic iodine: 99%

.HEPA Particulates: 99%

TODI ER2002-9994 Rev I Attachment I Page 210 of 22

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Comm"es Assumed Casc 2 43b. CR emergency ventilation intake filter efficiency: Proposed Case Charcoal Elemental iodine: 95%

Organic iodine: 95%

HEPA Particulates: 99%

44a. Unfiltered inleakage into CR during normal DR£97-0130, Rev.0 case I Used in Calc. DRE97-0130, Rev.0 and emergency ventilation mode: Base Case 263 scfmn Includes ingress/egressinleakage of 10 scfin.

44b. Unfiltered inleakage into CR during normal Assumed Case 2 and emergency ventilation mode: Proposed Case 600 scfmi

45. CR emergency ventilation air recirculation DRE97-0130, Rev.0 0 cfin Per Calc. DRE97-0130, Rev.0 Rate through filters

46. Atmospheric Dispersion Factors at EAB DREOI-0008, Rev.0 SBGTS Stack:

0-0.5 hr 6.98-5 s/im' 0.5-2 hr 3.59-6 sfm' MSIV leakage:

0-2 hr 2.02E-4 s/rn' TODI ER2002-9994 Rev I Attachment I Page 21 of 22

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47. Atmospheric Dispersion Factors at LPZ SBGTS Stack:

DRE01-0008, Rev.0

-0.5 hr 8.72E-6 s/r' 0.5-2 hr-2.48E6 s/m' 2-8 hr l.17E-6 s/m' 8-24 hr 8.08E-7 s/m3 14 day 3.58E-7 s/m3 4-30 day 1.12E-7 s/m' MSIV Leakage:

0-2 hr 2.1OE-5 s/m' 2-8 hr 9.08E-6 s/m' 8-24 hr 5.98E-6 s/m3 1-4 day 2.41E-6 s/m' 4-30 day 6.56E-7 s/m'

48. Offsite Breathing Rate RADTRAD Default 0-8 hr -

3.47E-04 m3 /s Values 8-24 hr -

1.75E-04 m' ls 1-30 day - 2.32E-04 m' /s TODI ER2002-9994 Rev 1 Attachment 1 Page 22 of 22