ML16260A101

Draft Fuel Handling Accident Dose Consequences Using AST Methods

ML16260A101
Person / Time
Site:	Farley
Issue date:	09/22/2016
From:	Southern Nuclear Operating Co
To:	Office of Nuclear Reactor Regulation
Williams S A, DORL/LPL2-2, 415-1009
Shared Package
ML16260A083	List: ML16260A097 ML16260A101 ML16260A109 ML16260A116 NL-16-0388, Draft Fuel Handling Accident Dose Consequences Using AST Methods NL-16-0388, Draft LOCA Dose Consequences Using AST Methods NL-16-0388, Draft License Amendment Request Regarding Alternative Source Team NL-16-0388, September 22, 2016, Public Meeting Presentation Slides
References
NL-16-0388
Download: ML16260A101 (5)

Text

FUEL HANDLING ACCIDENT DOSE CONSEQUENCES USING AST METHODS Licensee Document Number: SM-1080538201

-00 1, Version 2 Method/Computer Program Used:

RADTRAD Version 3.

03 Regulatory Guidance: RG-1.183, including Appendix B Model Discussion:

The calculation was performed to address a fuel handling accident (FHA) in the containment and in the Spent Fuel Pool (SFP) area of the Auxiliary Building. For the containment accident, the containment equipment hatch and the personnel airlock are presumed to be open and no credit is taken to close them. The open containment airlock could allow areas around the Control Room (CR) to become contaminated, so the calculation accounts for dose impacts of ingress/egress of the CR through the CR doors. Also, a small amount of CR envelop wall is only 1 foot thick, so the shine from the contaminated area through the wall is added to the CR operator dose. Doses in the CR are accumulated over an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> shift. Releases from the failed fuel are completed in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

For the accident in the SFP area of the Auxiliary Building, the accident releases also are completed in 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The activity is released to the environment through the plant vent stack, and credit is taken for filtration of the iodine isotopes through the Penetration Room Filtration System. Doses from this accident are bounded by the doses from an accident in containment.

Results and Acceptance Limits: (Note that rounding is applied to all values)

Release EAB (rem TEDE) LPZ (rem TEDE) Control Room (rem TEDE) Containment 2.4 0.9 1.0 Spent Fuel Pool 0.5 0.2 0.2 Acceptance Limit 6.3 6.3 5 FUEL HANDLING ACCIDENT DOSE CONSEQUENCES USING AST METHODS Key Assumptions and Inputs:

Source Term Parameters Parameter Value Reactor Power Leve l: 2775 MWt (+2% uncertainty = 2831 MWt)

Reactor Peaking Factor: 1.7 Fuel Movement Time: 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> post shutdown.

Number of Fuel Assemblies: 157 Number of Failed Assemblies: 1 Number of Failed Fuel Rods: 264 Core Cycle

-to-Cycle Augments: Isotope Factor Kr-85 1.15 Xe-133 1.05 Other Noble Gases 1.03 Other Iodines 1.03 Core Source Term:

Isotope Core Activity at 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> post Shutdown (curies)

Kr-85 7.2E+05 Xe-131m 8.1E+05 Xe-133 1.0E+08 Xe-133m 2.0E+06 Xe-135 2.0E+05 I-131 5.4E+07 I-132 4.6E+07 I-133 5.7E+06 I-135 4.1E+03 Fraction of Fission Product Inventory in Gap I-131 0.08 Kr -85 0.10 Other Noble Gases 0.05 Other Halogens 0.05 Overlaying Pool Depth 23 feet Pool Decontamination Factor Elemental:

5 00 Organic: 1 Iodine Chemical Form 0% Aerosol, 99.75% Elemental, 0.25% Organic

FUEL HANDLING ACCIDENT DOSE CONSEQUENCES USING AST METHODS Net Decontamination Factor 200 Net Scrubbed Release Activities:

Group Isotope 100-hr Core Inventory (Ci) Design Margin Gap Fraction Release to Water (Ci/MWt) DF Scrubbed Inventory (Ci/MWt) Noble Gases Kr-85 7.2E+05 1.15 0.10 3.2E-01 1 3.2E-01 Xe-131m 8.1E+05 1.03 0.05 1.6E-01 1 1.6E-01 Xe-133 1.0E+08 1.05 0.05 2.0E+01 1 2.0E+01 Xe-133m 2.0E+06 1.03 0.05 3.9E-01 1 3.9E-01 Xe-135 2.0E+05 1.03 0.05 3.9E-02 1 3.9E-02 Halogens I-131 5.4E+07 1.03 0.08 1.7E+01 200 8.5E-02 I-132 4.6E+07 1.03 0.05 9.1E+00 200 4.5E-02 I-133 5.7E+06 1.03 0.05 1.1E+00 200 5.6E-03 I-135 4.1E+03 1.03 0.05 8.1E-04 200 4.0E-06 Crelease = Core Inventory x Design Margin x F N H x Gap Fraction Nassembl y x 2775 x 1.02 FUEL HANDLING ACCIDENT DOSE CONSEQUENCES USING AST METHODS Containment Release: Parameter Value Containment Volume 2.03E6 Cubic Feet Mixing Volume in Containment 1.0E6 Cubic Feet Release Duration 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> Containment Hatch Flow Rate 55,000 cfm Containment Release Filtration 0% Personnel Airlock Flow Rate 1515 cfm Auxiliary Building Mixing Volume 37,875 cubic feet Personnel Airlock Release Filtration 0% Auxiliary Building Ventilation 1505 cfm to plant vent, 10 cfm to CR for ingress/egress Spent Fuel Pool Area Release: Parameter Value Fuel Handling Volume: 72,150 cubic feet Overlaying Pool Depth: 23 feet Fuel Handling Area Release Rate: 5,000 cfm PRF Filtration: 89.5% for iodine isotopes CR Parameters Parameter Value CR Volume 114,000 ft3 CR Isolation Mode Initiation Automatic at 60 Seconds CR Pressurization Mode Initiation Manually at 21 minutes CR Ventilation System Normal Flow Rate 2340 cfm < 60 seconds CR Ventilation Isolation Mode Flow Rate 600 cfm (1 minute to 21 minutes)

CR Ventilation Pressurization Makeup Rate 375 cfm > 60 seconds CR Ventilation System Recirculation Flow Rate 2700 cfm > 60 seconds CR Ventilation System Charcoal Filter Efficiencies Pressurization Filters 98.5% all iodines Recirculation Filters 94.5% elemental and organic 98.5% particulate CR Pressurization Mode Unfiltered Inleakage 325 cfm CR Ingress/Egress Unfiltered Inleakage 10 cfm throughout (location changes) CR Breathing Rate 3.5E-4 m 3/sec Occupancy Factors 0-8 hours 1.0 FUEL HANDLING ACCIDENT DOSE CONSEQUENCES USING AST METHODS CR Ventilation Summary:

Time Filtered Flow (CFM) Unfiltered Flow (CFM) 0 to 1 minute 0 2340 1 minute to 21 minutes 0 600 21 minutes to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 375 325 Note: For the FHA in Containment, the 10 CFM for ingress and egress to the CR goes from the Auxiliary Building to the CR through the CR door. For the FHA in the SFP area, the 10 cfm for ingress and egress is conservatively added to CR through the ventilation system and is unfiltered. This unfiltered inleakage starts at time 0 and continues through the entire accident (8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />).

Atmospheric Dispersion Factors (sec/m

3)  :

Containment Releases: Time (hr) EAB LPZ CR 0 - 2 7.6E-4 2.80E-4 8.79E-04 2 - 8 - 1.10E-4 6.77E-04 Plant Vent Releases: Time (hr) EAB LPZ CR 0 - 2 7.6E-4 2.80E-4 1.62E-03 2 - 8 - 1.10E-4 1.37E-03