LR-N04-0413, Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis

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Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis
ML042740529
Person / Time
Site: Salem  PSEG icon.png
Issue date: 11/10/2003
From: Drucker M
NUCORE
To:
Office of Nuclear Reactor Regulation
References
LR-N04-0413 S-C-ZZ-MEE-1805, Rev 0
Download: ML042740529 (11)
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- S-C-ZZ-AIEE-1805, RevisionOIRO 0)4' Date: 11/10/2003 TITLE: W\'aste Gas Decay Tank and Volume Control Tank Rupturc Accidents - AST Analysis Periodic Review Required: Yes No X 1.0 PURPOSE This engineering evaluation addresses the radiological consequences of both Waste Gas Decay Tank (WGDT) and Volume Control Tank (VCT) rupture accidents using Alternative Source Term (AST) methodology including TEDE dose criteria.

2.0 WGDT AND V'CT RUPTURE, SCENARIOS The current WGDT and VCT Rupture dose analysis of record (AOR) is a Stone &

Webster Calculation assigned PSE&G VTD Number 322257 Revision 4 (Ref. 7.2). Per the AOR, the noble gas activity inventories in the WGDT and VCT are released to the environment via the plant vent as an instantaneous puff (Ref. 7.2, Section 2.0). No credit is taken for activity hold-up or decontamination. The released activity is atmospherically dispersed to the CR and offsite dose receptors.

2.1 Comparison of N1'GDT and VCT Accident Activity Relcases Section 4.0 presents the WGDT and VCT activity inventories released to the environment as specified in the WGDT and VCT rupture dose AOR. The WGDT activity inventory specified in the AOR is nearly identical to the Gas Decay Tank activity inventory specified in Calculation RSAC-PSE-809 (Ref. 7.3, Table 2), with the sole difference being that Calculation RSAC-PSE-809 also addresses the presence of Xenon-131m in the tank activity inventory. For completeness, this engineering evaluation of a WGDT rupture accident releases to the environment the Xenon-I 31m activity inventory specified in Calculation RSAC-PSE-809.

The following table compares the WGDT and VCT activity inventories released to the environment. This comparison converts the WGDT and VCT activity inventories to an equivalent dose rate assuming that the released activity is dispersed within a one cubic meter cloud. The dose conversion factors used for this conversion are the effective TEDE for air submersion as listed in FGR-12 (Ref. 7.4, Table III.1). Per the following table, the dose rate due to the release of the WGDT activity inventory is greater than the dose rate due to the release of the VCT activity inventory. It is therefore concluded that the control room and offsite dose consequences of a puff release of the WGDT activity inventory bound the dose consequences of a puff release of the VCT activity inventory.

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S-C-ZZ-NIEE-1805, Revision 0IRO 0 *4 Date: 11/10/2003 TITLE: Waste Gas Decay Tank and Volutmec Control Tanlk lptutire Accidents - AST Analysis ISOTOPE WGDT VCT EFFECTIVE TEDE WGDT VCT INVENTORY INVENTORY DOSE CONVERSION FACTOR DOSE RATE DOSE RATE RELEASED TO RELEASED TO FOR AIR SUBMERSION IN A IN A ENVIRONMENT ENVIRONMEN [1 Sv = 100 Rem] 1 CUBIC METER 1 CUBIC METER (Section 4.1.1) (Section 4.1.2) (FGR-12. Table 111.1) [1 Ci = 3.7e10 Bq] CLOUD CLOUD (Ci) (Ci) (Sv-mr/Bq-sec) (Rem-m'/Ci-sec) (Remisec) (Remlsec)

Xe-131 m 2.9E+02 0.OE+00 3.89E-16 1.44E-03 4.2E-01 0.OE+00 Xe-133 3.5E+04 2.4E+04 1.56E-15 5.77E-03 2.OE+02 1.4E+02 Xe-1 33m 2.2E+03 1.5E+03 1.37E-15 5.07E-03 1.1E+01 7.6E+00 Xe-135 8.6E+02 6.8E+02 1.19E-14 4.40E-02 3.8E+01 3.OE+01 Xe-1 35m 0.OE+00 5.OE+01 2.04E-14 7.55E-02 0.OE+00 3.8E+00 Xe-138 O.OE+00 3.4E+00 5.77E-14 2.13E-01 0.0E+00 7.3E-01 Kr-85 1.5E+03 9.6E+02 1.19E-16 4.40E-04 6.6E-01 4.2E-01 Kr-85m 1.2E+02 1.OE+02 7.48E-15 2.77E-02 3.3E+00 2.8E+00 Kr-87 1.8E+01 2.7E+01 4.12E-14 1.52E-01 2.7E+00 4.1E+00 Kr-88 1.5E+02 1.4E+02 1.02E-13 3.77E-01 5.7E+01 5.3E+01 TOTALS: 3.1E+02 2.4E+02 3.0 ANALYSIS METHODOLOGY This engineering evaluation uses a conservative and simple radiological dose consequence analysis to evaluate the WGDT rupture accident. The assumptions, design inputs, and methodology described in this section are modeled in a RADTRAD computer code run, which calculates the WGDT rupture control room and offsite dose consequences.

This evaluation uses Version 3.02 of the RADTRAD computer code to calculate the potential radiological consequences of the WGDT rupture accident. The RADTRAD code is documented in NUREG/CR-6604 (Ref. 7.5). The RADTRAD code is maintained as Software ID Number A-0-ZZ-MCS-0225 (Ref. 7.6).

The noble gas activity inventory in the WGDT is conservatively released to the environment via the plant vent as an instantaneous puff. The puff release is modeled in the RADTRAD computer code run by modeling a small WGDT volume of 10 ft3 and a large release rate of 200,000 ft3 /minute.

Calculation S-C-ZZ-MDC-1912 Revision 0 (Ref. 7.7) is an ARCON96 code analysis that evaluates atmospheric dispersion between the Unit I plant vent and the control room (CR) HVAC air intake. Per the ARCON96 calculation, the X/Q value defining a release from the plant vent to the CR HVAC air intake during the first moments of the WGDT Rupture release (when the entire inventory is released to the environment) is 1.78e-3 sec/m3 .

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S-C-ZZ-MEDE-1805, Recision 9OIR-  ; Date: 11/10o2003 TITLE: W\'aste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis This engineering evaluation conservatively models only the CR normal mode of operation. No credit is taken for a switchover to the CR emergency mode of operation.

No credit is taken for filtration of the contaminated outside air that enters the control room via the HVAC system or via inleakage. No credit is taken for cleanup of the contaminated CR air by the emergency recirculation unit filters.

The remainder of the WGDT Rupture radiological consequence model is consistent with the control room and offsite modeling employed in Steam Generator Tube Rupture (SGTR) AST dose Calculation S-C-ZZ-MDC-1949, Revision OIRO (Ref. 7.8).

Section 4.0 summarizes the design input parameters used in the WGDT Rupture radiological consequence model. Figures I and 2 depict the WGDT Rupture model.

4.0 RADTRAD COMPUTER CODE INPUT DATA A single RADTRAD computer code run calculates the control room and offsite dose consequences of the WGDT rupture accident. The following files are input to the RADTRAD Code:

Plant Scenario File (PSF) = SWGDTOO.psf Nuclide Inventory File (NIF) = sgwdt ng def.txt Release File (RFT) = swgdt rft.txt Dose Conversion File (DCF) = sngsfgl 1&12.txt The following design input parameters are used in the WGDT rupture radiological consequence model. Figures I and 2 depict the WGDT rupture model.

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S-C-ZZ-1NlEE- 1805, Revision 013M Datc: 1 1/1012003 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis Design Input Parameter Value Assigned Reference 4.1 WGDT Source Term 4.1.1 WGDT activity inventory (based on 1% fuel Ref. 7.2, Section 4.1 defects, 3600 MWt for 497 EFPD, and an RCS Volume And Ref. 7.3, Table 2 of 10,890 ft3 )

Isotope Activity Isotope Activity Isotope Activity (Curies) (Curies) (C u ries)

Xe-131m 2.9 E+2 Xe-135 8.6 E+2 Kr-87 1.8 E+1 Xe-133 3.5 E+4 Kr-85 1.5 E+3 Kr-88 1.5 E+2 Xe-133m 2.2 E+3 Kr-85m 1.2 E+2 4.2 VCT Source Term 4.2.1 VCT activity inventory (based on 1% fuel defects, Ref. 7.2, Section 4.2 and 3600 MWt for 497 EFPD)

Isotope Activity Isotope Activity Isotope Activity (Curies) (Curies) (Curies)

Xe-133 2.4 E+4 Xe-135M 5.0 E+1 Kr-85m 1.0 E+2 Xe-133m 1.5 E+3 Xe-138 3.4 E+0 Kr-87 2.7 E+1 Xe-135 6.8 E+2 Kr-85 9.6 E+2 Kr-88 1.4 E+2 4.3 Activity Transport Model (Figure 1) 4.3.1 WGDT volume 10 ft. Assumed for a puff release 4.3.2 WGDT Rupture 200,000 ft'/minute Assumed for a puff release release rate 4.4 Control Room Model Parameters (Figure 2) 4.4.1 CR volume 81,420 ft- Ref. 7.8, Section 5.5.1 4.4.2 CR normal flow rate 11,320 cfm (for two air Ref. 7.8, Section 5.5.2 intakes) 4.4.3 CR occupancy factors Time (Hr) l_% l Ref. 7.8, Section 5.5.9 0-24 100 24-96 60 96-720 40 4.4.4 CR breathing rate 3.5E-04 m3/sec Ref. 7.8, Section 5.5.10 Pa-e 4 of II

S-C-ZZ-NIEE-1805, Revision OIRO 0 - 1 Date: 11/10/2003 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis Design Input Parameter I Value Assigned I Reference 4.4.5 Unit I CR air intake yJQs for Unit 1 Plant Vent release Time X/Q (see/m') Ref. 7.7, Section 8.2 0-2 1.78E-03 2-8 1.31 E-03 8-24 5.22E-04 24-96 3.77E-04 96-720 3.17E-04 4.4.6 CR Dose Conversion Per FGR- Il and FGR-12 Ref. 7.8, Sections 4.3.2 &

Factors 4.3.4 4.5 E:AB and LPZ Model Parameters 4.5.1 EAB atmospheric 1.3E-04 sec/m' Ref. 7.8, Section 5.6.1 dispersion factor (x/Q) 4.5.2 LPZ atmospheric dispersion factors (x./Qs)

Time (Hir) X/Q (see/m') Ref. 7.8, Section 5.6.2 0-2 1.86E-05 2-8 7.76E-06 8-24 5.01E-06 24-96 1.94E-06 96-720 4.96E-07 4.5.3 EAB breathing rate 3.5E-04 m3/sec Ref. 7.8, Section 5.6.3 4.5.4 LPZ brcathing rates Time (H1r) BR (m3/see) Ref. 7.8, Section 5.6.4 0-8 3.5E-04 8-24 1.8E-04 24-720 2.3E-04 4.5.5 EAB and LPZ Dose Per FGR-I 1 and FGR-12 Ref. 7.8, Sections 4.3.2 &

Conversion Factors 4.3.4 Page 5 of I

S-C-ZZ-MIEE-1805, lReisioi 01R0O-.a Date: 1 1/1012003

/0 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis 5.0 RADTRAD COMPUTER CODE RESULTS The WGDT rupture accident control room and offsite doses reported in the RADTRAD output file (SWGDTOO.oO) are shown in the following table:

WGDT Rupture Accident Doses (per RADTRAD output file SWGDTOO.oO)

Dose Recepltor lDose (Rem TDE l Control Room (Event Duration Dose) 2.0713-02 Exclusion Area Boundary (2-hour Dose) 4. 1 OE-02 (from 0 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />)

Lowv Population Zone (Event Duration Dose) 5.86E-03

6.0 CONCLUSION

S This engineering evaluation provides a radiological dose consequence analysis for the scenario of a SNGS WGDT rupture accident. Using conservative and simple methods, this engineering evaluation calculates the WGDT rupture control room and offsite doses reported in Section 5.0. These doses are trivially small compared to the 5 Rem TEDE control room and 25 Rem TEDE offsite dose criteria specified in 10 CFR 50.67 (Ref. 7.9).

This engineering evaluation also provides a scoping analysis that shows that the WGDT rupture control room and offsite dose consequences bound the corresponding VCT rupture dose consequences. Therefore, the VCT rupture control room and offsite dose consequences have sufficient margin and need not be recalculated.

7.0 REFERENCES

1. U.S. NRC Regulatory Guide 1.183, Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors, July 2000
2. PSE&G VTD Number 322257, Revision 4, "Radiological Dose Consequence at the EAB/LPZ and in the Control Room with Modified Control Room Ventilation Design - Waste Decay Tank and Volume Control Tank Rupture Accidents"
3. Calculation RSAC-PSE-809, Revision 0, Gas Decay Tank Activities for Salem Margin Recovery
4. Federal Guidance Report 12, EPA-402-R-93-081, Environmental Protection Agency
5. S.L. Humphreys et. al., "RADTRAD: A Simplified Model for Radionuclide Transport and Removal and Dose Estimation," NUREG/CR-6604, USNRC, April 1998 Page 6 of 11

S-C-ZZ-NMEE- 1805, RevisionQ B Date:

t10 11/10/2003 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis

6. Critical Software Package Identification No. A-0-ZZ-MCS-0225, Rev.0, RADTRAD Computer Code, Version 3.02
7. Calculation S-C-ZZ-MDC-1912, Revision 0, Control Room yjQs Using ARCON96 Code - Equipment Hatch & Plant Vent, and FHB Rollup Door Releases
8. Calculation S-C-ZZ-MDC-1949, Revision OIRO, "EAB, LPZ, & CR Doses -

Steam Generator Tube Rupture (SGTR) Accident - AST"

9. 10 CFR 50.67, "Accident Source Term" Page7of II

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S-C-ZZ-MIEE- 1805, Revision OHZR Date: 11/10/2003 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis 8.0 FIGURES Page 8 of II

S-C-ZZ-MEE-1805, Rcevision4RO Q I Date: 11/10/2003 TITLE: Waste Gas Decay Tank and V'olumc Control Tank Rupture Accidents - AST Analysis Page9of 11

  • It S-C-ZZ-MEE-1805, Revision 0 Date: 11/10/2003 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis 9.0 ATTACHMENTS One Diskette with the following electronic files (1 page):

Engineering Evaluation No: S-C-ZZ-MEE-I 805, Rev. 0 Comment Resolution Form 2 - Gopal J. Patel Certification for Design Verification Form-I RCPD Form-I 10.0 SIGNATURES 11/10/2003 Preparer Mark Drucker / CORE) Date 11/11/2003 Design Verifier (Gopal J. Patel / NUCORE) Date 4)

Dlesign Analysis Supervisor (Paul Lindsay / PSEG) i IT I Date 7 /0'l Page 10 of lI

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S-C-ZZ-NIEE-1805, RevisioirtRV-0 -O Date: 11/10/2003 TITLE: Waste Gas Decay Tank and Volume Control Tank Rupture Accidents - AST Analysis Attachment A I Diskette With Various Electronic Files Page 11 of 11

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