NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-002, Dose Rate Evaluation of Reactor Vessel Water Levels During Refueling for EAL Thresholds

Duane Arnold Energy Center, Calc No. NEE-323-CALC-002, Dose Rate Evaluation of Reactor Vessel Water Levels During Refueling for EAL Thresholds

ML17363A079
Person / Time
Site:	Duane Arnold
Issue date:	12/15/2017
From:	NextEra Energy Duane Arnold
To:	Office of Nuclear Reactor Regulation
Shared Package
ML17363A067	List: ML17363A069 ML17363A071 ML17363A072 ML17363A074 ML17363A075 ML17363A076 ML17363A078 ML17363A079 ML17363A082 ML17363A083 ML17363A085 ML17363A086 ML17363A088 ML17363A098 NG-17-0235, Attachment 1: Duane Arnold Energy Center, License Amendment Request TSCR-166, Redline Markup of NEI 99-01, Revision 6. Part 1 of 2 NG-17-0235, Attachment 1: Duane Arnold Energy Center, License Amendment Request TSCR-166, Redline Markup of NEI 99-01, Revision 6. Part 2 of 2 NG-17-0235, Attachment 2: Duane Arnold Energy Center, License Amendment Request TSCR-166, Clean Copy of the Proposed DAEC EAL Scheme NG-17-0235, Duane Arnold Energy Center - Calc No. NEE-323-CALC-003, Documentation of the RU1 Emergency Action Levels NG-17-0235, Duane Arnold Energy Center EAL Classification Matrix Hot Conditions (Modes 1, 2, 3) NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-001, Primary Containment Radiation EAL Threshold Determination NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-002, Dose Rate Evaluation of Reactor Vessel Water Levels During Refueling for EAL Thresholds NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-004, Revised Liquid Radiological EALs Per NEI 99-01 NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-005, Revised Gaseous Radiological EALs Per NEI 99-01 Rev. 06 NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-005, Revised Gaseous Radiological EALs Per NEI 99-01 Rev. 6 NG-17-0235, Duane Arnold Energy Center, Calc No. NEE-323-CALC-006, Correlation of Drywell Radiation Monitors for 300 Uci/Gm Dose Equivalent Iodine NG-17-0235, Duane Arnold Energy Center, License Amendment Request TSCR-166, Adoption of Emergency Action Level Scheme Pursuant to NEI 99-01, Revision 6, Development of Emergency Action Levels for Non-Passive Reactors. NG-17-0235, EAL Classification Matrix Cold Conditions (Modes 4,5, and Defueled)
References
NG-17-0235 Calc No. NEE-323-CALC-002
Download: ML17363A079 (38)

Text

Development of EAL Threshold values from NEE-323-CALC-002 Due to elevated background radiation levels on these monitors during plant operation (10-12 R/hr), the calculated threshold value was rounded to 5 (minimum serviceable threshold value accounting for scale of monitor) for ease of use by the EAL evaluator, and the " in Mode 5 only" caveat is added to the EAL usage. The resultant EALs are: RA2.2 Reading greater than 5 R/hr on ANY of the following radiation monitors (in Mode 5 only):

• NW Drywell Area Hi Range Rad Monitor, RIM-9184A

• South Drywell Area Hi Range Rad Monitor, RIM-9184B CS1/CG1 Core uncovery is indicated by ANY of the following:

• Drywell Monitor (9184A/B) reading greater than 5.0 R/hr CALC NO. NEE-323-CALC-00 2 'l ENERCON CAL C ULATION COVER 'Ir SHEET REV. 00 Exc eflence-Every pr oject Eve r y day. PAGE NO. 1 of 28 Do se Rate E v a lu a t i on of Reac t o r Ve s sel C l i ent: D ua n e Arnold Energy C en t er Ti t le: Wa ter Le vel s Du rin g Refuel i ng for EAL Th r esholds Project Identifie r: NEE-323 I tem C over Sh e et Item s Yes N o 1 D oes this calcula tion contain an y o p en ass umption s , i ncluding pre limin a ry D [gJ info rmati o n , th a t require c onfi r m ati on? (If YE S, ide ntify the as s umption s.) 2 Do es this c alcul ati o n serve a s a n " A l te rn ate Ca l cu l a t i on"? (I f YE S , i d e ntify t he d esi gn D [gJ verified calcula t ion.) D es i gn V e rified Cal c ulation No. --3 Do es this ca l c ul a tio n superse d e an existing C alcu l at ion? (I f YE S , iden ti fy the des ign D [gJ ve r i fied calculation

.) Supe rse ded Calculation No. --Scope of Revision:

Init i al Issue Revision Impact on Results: In i tial Issue Study C alculation D Final Calculation Safety-Related D Non-Safety-Related (Print Name and Sign) Originator:

Jay Bhatt Date: 12/12/17 Design Verifier 1 (Reviewer if NSR): Caleb T r aino r Date: 12/12/17 Approver:

Aaro n Holloway Date: 12/12/17 Not e 1: For no n-s a f e ty-r e lat ed ca l c ul a tion , d e s i gn v e rifi c atio n c an be substitu t ed by review.

ENERCON CALCULATION CALC NO. NEE-323-CALC-002 I Excellence

-Every project. £ very day. REVISION STATUS SHEET REV. 00 CALCULATION REVISION STATUS REVISION DATE DESCRIPTION 00 12/12/17 Initial Issue PAGE REVISION STATUS PAGE NO. REVISION PAGE NO. REVISION All 00 APPENDIX/ATTACHMENT REVISION STATUS APPENDIX NO. NO.OF REVISION ATTACHMENT NO.OF REVISION PAGES NO. NO. PAGES NO. A 1 00 1 5 00 B 2 00 C 1 00 Page 2 of 28 ENERCON TABLE OF CONTENTS E.xceflenc,:-Every project £very day. Section 1.0 Purpose and Scope 2.0 Summary of Results and Conclusions 3.0 References 4.0 Assumptions 5.0 Design Inputs 6.0 Methodology 7.0 Calculations 8.0 Computer Software 9.0 Impact Assessment List of Appendices Appendix A -Electronic File Listing Appendix B -DAEAL.xlsx Sheets Appendix C -SCALE Input List of Attachments Attachment 1 -Calculation Preparation Checklist Page 3 of 28 CALC NO. NEE-323-CALC-002 REV. 00 Page No. 4 4 5 6 8 13 14 27 28 # of Pages 1 2 1 # of Pages 5

.~ ENE RCON Exce ll enc,-Eve,y projecr. Every day, 1.0 Purpose and Scope Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels1---------

---

j During Refueling for EAL Thresholds REV. 00 The purpose of this calculation is to evaluate dose rates with water at the top of active fuel in the reactor vessel during cold shutdown or refueling operations in order to set Emergency Action Level (EAL) thresholds (RA2, CS1, CG1) per NEI 99-01 [Reference 3.5]. The dose rates are calculated at the locations of the drywell monitors 9184A/B so that dose rate measurements by these devices can be correlated to the water level in the core , upon failure of other water level detection systems. This calculation is nonsafety-related as the results of the calculation do not affect the design basis or safety-related systems structures or components.

These results are best estimates based on as-built conditions and provide information to operators with respect to classifying an emergency, therefore no acceptance criteria is required. 2.0 Summary of Results and Conclusions The dose rates just prior to the core being uncovered (i.e. water at the top of the active fuel) are shown in the table below. Note that the results presented below are calculated dose rates and do not account for background radiation or any installed detector check sources. Model De s cription Head Off Head On 1 This value is off scale low. Table 1 -Dose Rate at Top of Active Fuel Drywell Monitor 9184A Reading r 1.81 1.11 Drywell Monitor 9184B Reading R/hr 1.68 7.41 E-01 1 Page 4 of 28 Drywell Monitor (9184A/B)

Range R/hr 1 to 1E+7 1 to 1 E+7 Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels 1----------------, ENERCON Excellence-Every pr o;ect. Every day. 3.0 References During Refueling for EAL Thresholds REV. 00 3.1 "Standard Composition Library," ORNL/NUREG/CSD-2N1/R6 , Volume 3 , Section M8, March 2000 3.2 CGDG-SCALE-6.1.2, Rev 00, Commercial Grade Dedication SCALE Version 6.1.2 3.3 CGDG-MCNP6-V1

.0, Rev 00, Commercial Grade Dedication MCNP6 Version 1.0 3.4 ANSI/ANS 6.1.1-1977, Neutron and Gamma Flux-To-Dose Conversion Factors 3.5 NEI 99-01, Rev. 6, "Development of Emergency Action Levels for Non-Passive Reactors" 3.6 I.RIM-V115-01, Rev. 10 , " Victoreen Model 876A Containment Radiation Monitor Calibration" 3.7 NUREG 1940 , " RASCAL 4: Descriptions of Models and Methods" 3.8 CAL-ROO-PUP-008, Rev. 03, " Non-LOCA Radiological Consequence Dose with Alternate Source Term" 3.9 RFP 110, Rev. 45, "Refueling Procedure-Reactor Pressure Vessel Disassembly" 3.10 Technical Specifications , Section 1.1 3.11 Technical Specifications , Section 4.2.1 3.12 NUREG 1754, " A New Comparative Analysis of LWR Fuel Designs" 3.13 BECH-M009 , Rev. 14, " Equipment Locations Reactor Building Section-GG" 3.14 BECH-C405 , Rev. 14, "Reactor Building Floor Plan@ El. 757'-6"" 3.15 NG-17-0156, Proprietary Data Transmittal to ENERCON 3.16 BECH-M405, Sh 04, Rev. 24, " Instrument Points and Rack Locations Diagram Plans at Elevs 812'-0" & 833'-6"" 3.17 NG-88-0966, " G.E. Fuel Damage Documentation/Dose Rate Calculations" 3.18 C003-029, Rev. 0, "Drywell Cylindrical Shell & Cone" 3.19VS-01-06, Rev. 4, "Top Head Assembly" 3.20 BECH-C511, Rev. 5, "Reactor Building RPV Ped Dev. Elev. & Sect's" 3.21 BECH-C514, Rev. 1, " Drywell Interior Biological Shield Wall Reinforcing Sections" 3.22 BECH-C-516 , Rev. 6, "Drywell Interior Biological Shield Wall Plans El. 816'-3 %" to El 779'-1 Yi"" 3.23 BECH-M405, Sh 02, Rev. 71 , "Instrument Points & Lines Diagrams Plan at Elev 757'-6"" 3.24APED-B-31-2816-001, Rev. 5, "Outline Reactor Recirculating Pump" Page 5 of 28

.._ ENERCON Excellence-Every p roject. Every day. Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels f-------------------i During Refueling for EAL Thresholds REV. 00 3.25 FSAR Section 4.3.2.1, and Section 9.1 3.26 CAL-M98-058, Rev. 1, " ADS Accumulator Size Verification" 4.0 Assumptions 4.1 The core is homogenized based on the typical 1Ox10 fuel assembly dimensions, taking into account the fuel rods and space between. Any small variations in fuel parameters will have a negligible effect on containment dose rates. The cladding is modeled as Zircaloy 4 in lieu of ZIRLO; this is acceptable due to the similarity of the materials.

4.2 Any non-fuel hardware , including rod end plugs, is ignored in the active fuel region. This is acceptable since the primary self-shielding occurs in the fuel itself, and there may be some unknown streaming effects through the non-fuel hardware.

This homogenization takes into account the presence of water when calculating the isotopic weight fraction and homogenized density. For the case with the reactor vessel head in place , the region between the head and the active fuel region is homogenized based on the actual mass of the upper internals over the entire region. Homogenization of source regions and shields is acceptable due to the insignificant effects on the detector response given the model geometry.

4.3 The composition of the containment structure and components are based on the values in the SCALE standard composition library [Reference

3. 1]. These material properties are commonly used in shielding applications, and are acceptable for modelling the structures and components used to determine the best estimate response at the detector locations.

4.4 The minimum period of decay after reactor shutdown before moving fuel is 60 hours6.944444e-4 days <br />0.0167 hours <br />9.920635e-5 weeks <br />2.283e-5 months <br /> [Reference 3.8, Section 4.3.8]. This calculation assumes a decay time of 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> to allow EAL thresholds to be determined for reactor vessel conditions that exist prior to the commencement of fuel movement which is representative of the applicable operating modes (cold shutdown, refueling).

This decay time is appropriate to produce best estimate results for both the head on and head off configurations. 4.5 The hardware in the upper internals region between the active fuel region, reactor recirculating pumps and reactor vessel head is assumed to be stainless steel type 304. While the actual composition of the hardware may vary slightly, small variations in the material will have a negligible effect on the dose rate response at the detectors.

4.6 It is assumed that the water below the active fuel region is liquid at a constant temperature.

Using a density of 0.9982 g/cm 3 is common in shielding Page 6 of 28 ENERCON Exe<!llence-Every pro1ect. Every day. Dose Rate Evaluation of CALC NO. N EE-323-CALC-002 Reactor Vessel Water Levels 1---------------------1 During Refueling for EAL Thresholds REV. 00 applications.

Any water above this region would be steam with little shielding value. 4.7 The source term is gene r ated shortly after shutdown, therefore , the fuel gamma sou r ce term will predominate and the neutron-gamma and hardware activation can be neglected.

4.8 The high range detectors read out in roentgen per hour (R/h) which is a measurement of exposure rate , while the MCNP output is provided in mrem/h which is a measurement of the equivalent dose rate that represents the biological effects of ionizing radiation.

It is assumed that 1 R is approximately 1000 mrem. This is acceptable as only the gamma source term is considered.

4.9 The roof of the Reactor Building is modeled as 0.5 inches of stainless steel. This will account for any scatte r ing interactions that may contribute to the response at the detector.

The magnitude of the detector response due to scattering off of the roof will be small due to the geometry a nd amount of shielding in the model , and is therefore acceptable.

4.10 Automatic Depressurization System Accumulators 1 R003A/B/C located on the 775'-11 Yi" elevation are not included in the model. The size of the accumulators are 200 gallons [Reference 3.26]. This is relatively small compared to the geometry of the model, and the corresponding scatter interactions will not have a significant impact on the detector response.

Page 7 of 28 u ENERCON Dose Rate Eva l uation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levelst-----------------, Excellence-Every project. Every day. 5.0 Des i gn Inputs During Re f ueling for EAL Thresholds 5.1 Fuel Assembly Parameters REV. 00 The fo ll owing fuel assembly parameters are used to homogenize the core in the MCNP model. They are based on typica l fuel assembly values for 1Ox10 fue l. Table 2 -Design I nput Fuel Assembly Parameters Parameters Fuel type # of Assemblies in Core # Fuel rods per assembly Pitch Density (% of theoretical)

Fuel pellet OD Fuel rod OD Clad thickness Active Jen th 5.2 Model D i mensions Value lOxlO 368 92 0.51 95 0.336 0.395 0.026 144 Unit [in] [in] [in] [in] m Reference 3.25 3.11 3.12 3.12 3.12 3.12 3.12 3.12 3.12 The following elevations and dimensions are based on the assoc i ated dra w ings or other reference.

Some parameters are estimated using drawing scales w h en exact dimensions are not provided.

Table 3 -Design Input Dimensions Dimension ft in cm Reference Pedestal inner radius 8 243.84 3.20 Pedestal outer radius 12 365.76 3.20 Reactor vessel inner diameter 185.375 470.85 3.15 Reactro vessel thickness 5 12.70 3.15 Drywell spherical portion radius 31.5 960.12 3.17 Figure 2 Concrete around drywell spherical 36 9 1120.14 3.14 portion(x and y directions radius) Drywell cylindrical portion radius 17 518.16 3.16 Drywell Iiner thickness 0.75 1.91 3.18 Concrete around drywell cylindri-22 9 693.42 3.16 cal portion (x and y directions)

Reactor Building (x and y direc-140 4267.20 3.14 tions) Reactor Building Roof Thickness 0.5 1.27 Assumption 4.9 Height of active fuel 144 365.76 3.12 Vessel Height 704.5 1789.43 3.15 Page 8 of 28 Dose Ra t e Evaluat io n of CALC NO. N EE-323-CALC-002 Reactor Vesse l Water Levels ENERCON Excellence

-Every pro1ect. Every day. During Re f ueling for EAL RE V. 00 Thresholds Dimension ft in cm Reference Reactor vessel head thickness 3.9375 10.00 3.19 Distance from vessel O to bottom of 200.94 510.39 3.15 , 3.12 active fuel Bio shield inner radius 9 6.25 290.20 3.21 Bio shield outer radius 11 8.25 356.24 3.21 Reactor recirculating pump height 17 2 523.24 3.24 Reactor recirculating pump radius 2 9 83.82 3.24 Detector RE-9184A distance from 121.92 3 .23 [Scaled] origin (x plane) Detector RE-9184A distance from 13.33 406.29 3 .23 [Scaled] origin (y plane) Detector RE-9184B distance from 6 182.88 3 .2 3 [Scaled] origin (x plane) Detector RE-9184B distance from 365.76 3.23 [Scaled] origin (y plane) Reactor Recirculating Pump IP-12 365.76 3.23 [Scaled] 201A distance from origin (x plane) Reactor Recirculating Pump IP-12 365.76 3 .23 [Scaled] 201A distance from origin (y p l ane) Reactor Recirculating Pump IP--12 -365.76 3.23 [Scaled] 201B distance from origin (x p l ane) Reactor Recirculating Pump IP--12 -365.76 3 .23 [Scaled] 201B distance from ori in lane Table 4 -Design Input Elevations 2 Dimension:

ft. in cm Reference Drywe ll Equator 766 0.5 0.00 3.13 Vesse l 0 772 5.5 195.58 3.15 Bottom of pedestal elevation 742 9 -709.93 3.13 Top of cylindrical portion of drywell 855 2711.45 3.13 concrete Top of Reactor Build i ng 897 6 4006.85 3.13 Detector elevation 760 -184.15 3.17 Top of p edesta l/ bottom of bio shield 770 10.5 147.32 3.20 Top of bio shie l d 816 3.25 1530.99 3.22 Rea c tor recircu l atin 748 8.5 -528.32 3.13 2 All e l e v at io ns listed i n centimeters are relati v e t o the equat o r o f the drywe ll e l evation o f 766' 0.5 [Rence 3.1 3]. Page 9 of 28 ENERCON Excellence-Every p roject. Every <J oy. Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levelst---------

---_____, During Refue l ing for EAL Thresholds REV. 00 5.3 Core Isotopic Inventory Core isotopic activities in Ci/MWt are taken from Reference 3.7 Table 1-1. A table of the input values is shown in Table 5 , below. The activities in Ci are determined by multiplying by the rated thermal power of 1912 Mwt taken from Reference 3.10. Table 5 -Core Source Term Isotope Ci/MWt Ci Isotope Ci/MWt Ci Ba-139 4.74E+04 9.06E+07 Rh-105 2.81E+04 5.37E+07 Ba-140 4.76 E+04 9.1 0 E+07 Ru-103 4.34E+04 8.30E+07 Ce-141 4.39E+04 8.39E+07 Ru-105 3.06E+04 5.85E+07 Ce-143 4.00E+04 7.65E+07 Ru-106 1.55E+04 2.96E+07 Ce-144 3.54E+04 6.77E+07 Sb-127 2.39E+03 4.57E+06 Cm-242 1.12E+03 2.14 E+06 Sb-129 8.68E+03 l.66E+07 Cs-134 4.70E+03 8.99E+06 Sr-89 2.41E+04 4.61E+07 Cs-136 1.49E+03 2.85E+06 Sr-90 2.39E+03 4.57E+06 Cs-137 3.25E+03 6.21E+06 Sr-91 3.01E+04 5.76E+07 1-131 2.6 7E+04 5.11E+07 Sr-92 3.24E+04 6.19E+07 1-132 3.88E+04 7.42 E+07 Tc-99m 4.37E+04 8.36E+07 1-133 5.42E+04 1.04E+08 Te-127 2.36E+03 4.51E+06 1-134 5.98E+04 1.14E+08 Te-127m 3.97E+02 7.59E+05 1-135 5.18E+04 9.90E+07 Te-129 8.26E+03 1.58E+07 Kr-83m 3.05E+03 5.83E+06 Te-129m l.68E+03 3.21E+06 Kr-85 2.78E+02 5.32E+05 Te-131m 5.41E+03 1.03E+07 Kr-85m 6.l 7E+03 l.18E+07 Te-132 3.81E+04 7.28E+07 Kr-87 1.23E+04 2.35 E+07 Xe-131m 3.65E+02 6.98E+05 Kr-88 1.70E+04 3.25E+07 Xe-133 5.43E+04 1.04E+08 La-140 4.91E+04 9.39E+07 Xe-133m 1.72E+03 3.29E+06 La-141 4.33E+04 8.28E+07 Xe-135 l.42E+04 2.72E+07 La-142 4.21E+04 8.05E+07 Xe-135m 1.15E+04 2.20E+07 Mo-99 5.30E+04 1.01E+08 Xe-138 4.56E+04 8.72E+07 Nb-95 4.50E+04 8.60E+07 Y-90 2.45E+03 4.68E+06 Nd-147 1.75E+04 3.35E+07 Y-91 3.17E+04 6.06E+07 Np-239 5.69E+05 1.09E+09 Y-92 3.26E+04 6.23E+07 Pr-143 3.96E+04 7.57E+07 Y-93 2.52E+04 4.82E+07 Pu-241 4.26E+03 8.15E+06 Zr-95 4.44E+04 8.49E+07 Rb-86 5.29E+Ol l.01E+05 Zr-97 4.23E+04 8.09E+07 Page 10 of 28 Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levelsf----

---

1 LI ENERCON Excellencr-Every project. Every day, During Refueling for EAL Thresholds 5.4 Material Compositions REV. 00 The following compositions used in the MCNP model are taken or developed from the SCALE standard composition library (Reference 3.1] and are shown in Table 6. Table 6 -Scale Standard Compositions used in MCNP Model Material Isotope Weight Fraction Zry-4 Zr 0.9823 (6.56 g/cm 3) Sn 0.0145 Cr 0.0010 Fe 0.0021 Hf 0.0001 U02 U-235 0.0348 (10.412 g/cm 3) U-238 0.8466 0 0.1186 Air C 0.0001 (1.21E-03 g/cm 3) N 0.7651 0 0.2348 Water H 0.1111 (0.9982 g/cm 3) 0 0.8889 SS-304 Fe 0.6838 (7.94 g/cm 3) Cr 0.1900 Ni 0.0950 Mn 0.0200 Si 0.0100 C 0.0008 p 0.0004 Concrete 0 0.5320 (2.30 g/cm 3) Si 0.3370 [KENO Regular Ca 0.0440 Concrete Standard A l 0.0340 Mix] Na 0.0290 Fe 0.0140 H 0.0100 Carbon Steel C 0.0100 (7.82 g/cm 3) Fe 0.9900 Page 11 of 28 ENERCON Excellence-Every pr oject. E v ery day.. 5.5 Upper Internals Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels>------------------<

During Refueling for EAL Thresholds REV. 00 The following weights are used in the MCNP model for the region between the active fuel and the reactor vessel head [Reference 3.9, Appendix 8.9]:

• The weight of stainless steel for the moisture separator is 83,000 lbs.

• The weight of stainless steel for the steam dryer is 50,000 lbs. 5.6 The drywell (9184 A/8) and torus (9185 A/8) radiation monitor ranges (1 to 10 7 R/hr) are taken from Reference 3.6. 5.7 ANSI/ANS-1977 Flux to Dose Factors Flux to dose conversion factors are taken from ANSI/ANS-6.1.1-1977

[Reference 3.4] and are shown in Table 7. Table 7 -ANSI/ANS-6

.1. 1-1977 Flux to Dose Factors MeV mrem/hr/(y/cm 2/s) MeV mrem/hr/(y/cm 2/s) 0.01 3.96E-03 0.8 l.68E-03 0.03 5.82E-04 1 1.98E-03 -~--0.05 2.90E-04 2.2 3.42E-03 -0.07 2.58E-04 2.6 3.82E-03 Page 12 of 28 ENERCON Excellence-Every project. £very day. 6.0 Methodology Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levelsf----

---

1 During Refueling for EAL Thresholds REV. 00 The reactor source terms are decayed to 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> with ORIGEN-S of the SCALE 6.1 code package, Reference 3.2. The results are used to bin design input isotope specific activities into energy dependent photon bins. These energy specific photon emission bins are used as input for the energy distribution described by the MCNP source definitions.

The MCNP6, Reference 3.3, Monte Carlo transport code is used to determine the dose rates via the flux to dose conversion factors in Table 7, while accounting for shielding and particle transport.

The detailed engineering drawings are converted into MCNP surface and cell cards in the dimensions shown in Table 3 and Table 4. The radiation monitors of interest are modeled as point detectors to determine the expected dose rate for those detectors.

The dose rates are calculated for two reactor refueling conditions

1. With Head -the reactor is modeled with a 3.9375 inch carbon steel plate as indicated in Table 3, which is additional attenuation between the source and detector.

The mass of the moisture separator and steam dryer is homogenized between the active fuel region and the vessel head. 2. Without head -the reactor is modeled with air between the active fuel zone and containment.

3. A sensitivity case is run with a mirror surface at the top of the drywell to ensure the modeling of the drywell cap would not significantly affect the response at the tector locations due to scattering.

Variance reduction is accomplished with a geometric importance map that is imposed on the homogenized core. In addition, cell based importance weighting and source biasing (see Section 7.5) are utilized to improve the variance reduction of the simple geometric scheme. A superimposed weight window mesh is utilized where necessary to improve variance. The weight windows are iteratively generated using the MCNP weight windows generator card. All final dose rates presented in this calculation include weight windows variance reduction.

Page 13 of 28

• ENERCON Excellence-Every pro1ecr. Every doy. 7.0 Ca l culation 7.1 Source Terms Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels,___

___________

---< During Ref u e l ing for EAL Thresholds REV. 00 The ORIGEN-S input deck, DAECEAL.inp, is provided in Appendix C. Th i s input produces a simp l e case where the isotopic composition from Table 5 is decayed. T h e isotope is specified in the 73$$ card using the special identifier descr i bed i n Section F7.6.2 of the ORIGEN-S manual , and the activity in curies is specified in the 74** card. The time steps for the decay are given on the 60** card in hours. Although multiple time steps are calculated, the source term with 50 hours5.787037e-4 days <br />0.0139 hours <br />8.267196e-5 weeks <br />1.9025e-5 months <br /> decay time is used in this calculation to model the core short l y after shutdown.

The output of the decay is given in terms of photons/s/Energy-Group , which is automatically normalized in the MCNP input. The results of this calculation are summarized below in Table 8. These values are used in the MCNP input source definition.

Table 8 -Binned Total Core Source Term Energy Group Energy Boundaries (Me V) Photons/sec 1 0.01-0.05 2.028E+19 2 0.05-0.1 6.572E+18 3 0.1-0.2 l.557E+19 4 0.2-0.3 9.672E+18 5 0.3-0.4 3.582E+18 6 0.4-0.6 7.837E+ 18 7 0.6-0.8 l.373E+ 19 8 0.8-1 2.132E+18 9 1-1.33 4.942E+l 7 10 1.33-1.66 3.579E+18 11 1.66-2 6.576E+16 12 2-2.5 7.518 E+16 13 2.5-3 l.110E+17 14 3-4 8.689E+14 15 4-5 l.553E+10 16 5-6.5 2.568E+08 17 6.5-8 3.792E+07 18 8-10 8.041E+06 19 10-11 4.352E+05 tota l s 8.3 7 E+19 Page 14 of 28 ENERCON Excellence-Every project Every day. Dose Rate Evaluation of CALC NO. N EE-323-CALC-002 Reactor Vessel Water Levels1-------

---

i During Refueling for EAL Thresholds REV. 00 7.2 MCNP Model Core Homogenization The source term is given for the entire core, therefore, the self-shielding from the assemblies is an important part of the dose rate response.

For simplicity, the core is modeled as a three dimensional cylinder with a uniformly distributed spatial particle distribution.

The calculations for determining the mass of fuel, cladding and water for the core and the resulting density are shown below. The inputs are based on the dimensions in Table 2. Assembly Width= (Array Size -1) x pitch+ Rod OD = (10 -1)(0.51in)

+ 0.395in = 4.985 in Active Fuel Region Area= (Assembly Width)2 x Number of Assemblies in Core = ( 4.985in)2 x 368 = 9144.883 in 2 Active Fuel Equivalent Radius = )Active Fuel Region Area; rr = j9144.883 in 2 /rr = 53.953 in Rod Volumeu 0 2 = rr(Pellet Radius)2 x Active Length= rr(0.168 in)2 (144 in) = 12.768 in 3 g cm 3 Rod Massuo = p x V = (10.412-)

(12.7682 in 3) (2.54-.-)

= 2178.54 g 2 CT m Number of Fuel Rods Assembly Massu 0 2 = Rod Mass x A bl = (2178.54 g)(92) ssem y = 200.43 kg (OD 2 ID 2) Clad Volume= rr 4-4 x Active Length [(0.395 in)2 (0.343 in)2] ) 3 = (rr) 4 -4 (144 in = 4.34 in g cm 3 Rod MaSSzry-4 = p x V = ( 6.56 cc) ( 4.34 in 3) ( 2.54 in) = 466.5 g Page 15 of 28 ENERCON Exc e llenc,-Eve,y p roject. E v e,y d ay. Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels,__

___________

____, During Refueling for EAL Thresholds REV. 00 Number of Fuel Rods Assembly MaSSzry-4 = Rod Mass x bl = (466.5g)(92)

= 42.92 kg Assem y Assembly H 2 0 Volume = [(Assembly Width)2 -n(Rod Radius)2 x Number of Fuel Rods] x Active Length = [(4.985 in)2 -(rr)(0.1975 in)2(92)](144 in)= 1955 in 3 ( g)(1955)( cm)3 Assembly MassH O = p x V = 0.9982-. 3 2.54-.-= 31.98 kg 2 cc m m Assembly Volume= Active Length x (Assembly Width)2 = (144 in)(4.985 in)2 = 3578.4 in 3 . Total Mass 1000g/kg(200.43

+ 42.92 + 31.98) kg Density= = 3 = 4.70 g/cc Volume 3578.4 in 3 ( 2.54 ~r;:) The corresponding isotopic composition for the homogenized active fuel region is calculated based on the compositions in Table 6. An example calculation for the mass fraction of U-235 is included below. Assembly Massuo Mass Fraction U235 = T l M 2 x weight fraction U235 ota ass 200.43 kg ----------

X 0.0348 = 0.0253 (200.43 + 42.92 + 31.98) kg The remaining calculations for the homogenization are done in the worksheet Compositions of the EXCEL workbook DAEAL.xlsx and are shown in Appendix B. The isotopic compositions are calculated with the water level above the top of the fuel. Note that the EXCEL workbook uses additional significant figures. Page 16 of 28

\A ENERCON Excellence

-Every p rojecr. Every d ay. ZA IDNu m b er 9 223 5 9223 8 8016 40000 50000 24 000 26 000 7 2 000 1001 Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels 1---------------<

During Refueling for EAL Thresholds REV. 00 Table 9 -Homogenizatio n of Active Fuel Region A tom M ass Frac t ion Ac ti ve F u el Regio n Homoge ni ze d U-235 0.025 3 U-23 8 0.61 63 0 0.1896 Zr 0.15 31 Sn 0.00 23 Cr 0.00 02 Fe 0.0003 H f 0.000 0 H 0.012 9 7.3 MCNP Model Upper Internals Homogenization For the case with the r eactor vessel head in place, the steam dryer and moisture separator region are modeled as a discrete cylinder with a uniformly distributed homogenized material to account for the mass of stainless steel between the active fuel height and reactor vessel head. The homogenization accounts for the mass of metal from Section 5.5 (assumed stainless steel type 304 per Assumption 4.5) distributed evenly across the volume between the active fuel height (2=1071.73 cm) and the head (2=1985.01 cm). Mass Upper Int ern als= (83000 lb+ 50000 lb) ( 453.59 ~) = 6.033 x 10 7 g The mass is divided by the volume of the region between the active fuel height and the reactor vessel head to determine the density. D e nsit y Upp e r I n t e rnals = Mass Upp er Internal s+ V = 6.033 x 10 7 g + (913.28cm x (rr(2 3 5.43cm)2) = 0.379~ cc 7.4 MCNP Model Geometry The following MCNP model geometry is based on the containment dimensions summarized in Table 3 and Table 4. The model only focuses on the primary systems and components that provide shielding or reflection from the core to the radiation monitors.

These components include the reactor vessel, recirculation pumps, pedestal, biological shield and drywell. VISED plots of the model geometry are provided in Figures 1-3. The MCNP surface cards with the model dimensions (cm) are shown in Figure 4, and the cell cards are shown in Figure 5 for the cases with no reactor vessel head. A VISED plot of the model with the reactor vessel head is shown in Figure 6. Areas that are not of interest Page 17 of 28 ENERCON f.xcellenct-Every pro;ect. Every day. Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels,__

___________ ___, During Refueling for EAL Thresholds REV. 00 are given an importance of zero (white areas) so MCNP will not track particles in locations that will not contribute to the detector response. Figure 1 X-Z VISED Plot of Reactor Vessel (No Head) _. +-12.70 cm 1789.43 cm + .. 470.85cm Homogenized Core ---1--.....;, Water Page 18 of 28 Air Reactor Vessel Biological Shield ENERCON Exceflence-E.very project. E11ery day, Dose Rate Evaluation of CALC NO. N EE-323-CALC-002 Reactor Vessel Water Levelsf---

---

1 During Refueling for EAL Thresholds REV. 00 Figure 2 Vised Plot of Drywe/1 and Reactor Building 3 Radiation

---

1-.........

-Monito r Pump Reactor Building Drywell Pedestal Radiation Mon i tor Pump 3 Radiation monitors are not on the same plane shown above. They are included for visualization purposes only. The VISED Plot was rotated around the Z axis until the Recirculating Pumps were visible. Page 19 of 28 Dose Rate Evaluation of Excellence-Every pro;ect. Ew:ry day, CALC NO. N EE-323-CALC-002 Reactor Vessel Water Levels _____________ ---1 During Refueling for EAL REV. Thresholds 00 LI ENERCON Figure 3 X-Y Vised Plot of Detecto r s and Reactor Recirculating Pumps at Elevation 760'-0" 4 Radiation 4 Detectors are included for visualization purposes only. Page 20 of 28 Dose Rate Evaluation of CALC NO. N EE-323-CALC-002 Reactor Vessel Water Levels f------------------1 .. ENERCON Excellence-Every pro1ec1. Every day. During Refueling for EAL Thresholds REV. 00 Figure 4 MCNP Model Surface Cards 5 c surfaces 1 rec O O 705.97 0 0 365.76 137.045 2 rec O O 208.28 0 0 1776.73 235.43 3 rec O O 195.58 0 0 1789.43 248.13 4 rpp -1120.14 1120.14 -1120.14 1120.14 -1120.14 821.86 5 so 960.12 6 so 958.21 7 pz -709.9 3 8 rec O O -709.93 0 0 857.25 243.84 9 rec O O -709.93 O O 857.25 365.76 81 rec O O 147.32 0 0 1383.67 290.20 91 rec O O 147.32 0 0 1383.67 356.24 82 rec 365.76 365.76 -528.32 O O 523.24 83.82 92 rec -365.76 -365.76 -528.32 O O 523.24 83.82 10 pz 195.58 11 pz 82 1.86 12 rec O O 821.86 0 0 1889.59 5 1 8.16 13 rec O O 821.86 0 0 1889.59 516.25 14 rpp -693.42 693.42 -6 93.42 693.42 821.86 2711.45 15 pz 1071. 73 16 pz 1985.01 17 rpp -4267.2 4267.2 -4267.2 4267.2 2711.45 4006.85 18 rpp -4 267.2 4267.2 -4267.2 4267.2 4006.85 4008.12 19 pz 147.32 20 pz 1530.99 28 rec O O 1985.01 0 0 10.00 248.13 101 pz 742.546 102 pz 779.1 22 103 pz 8 1 5.698 104 pz 852.274 105 pz 888.85 106 pz 925.246 107 pz 962.002 108 pz 998.578 109 pz 1035.154 110 pz 1071.73 $ Active Fuel Region $ Reactor Pressure Vessel Inner Surface $ Reactor Pressure Vessel Outer Surface $ Concrete Spher port drywell outer $ Spher portion of drywell outer surface $ Spher portion of drywell liner surface $ Bottom of Pedestal Elevation

$ Pedestal Inner Surface $ Pedestal Outer Surface $ Bio Shield Inner Surface $ Bio Shield Outer Surface $ Recirc Pump IP-201A $ Recirc Pump IP-201B $ Vessel 0 $ Transition Spherical to Cylindrical

$ cylin port drywell co n crete surface $ cylin port drywell liner surface $ Concrete cylin port drywell outer $ Water Elevation Surface $ Top of RPV (head level) $ Reactor building above drywell $ Reactor building roof $ Top of Ped Elevation/Bottom Bio Shield $ Top of Ped Elevation/Bottom Bi o Shield $ Reactor Head 5 The surface card for the MCNP model without the reactor vessel head does not have surface 28. Page 2 1 of 28 ENERCON Exce ll ence-Ev ery pr o j ec t. Every d a y. C cells 101 1 -4.49 101 10 2 1 -4.49 -1 101 -10 2 103 1 -4.49 -1 102 -103 104 1 -4.49 -1 103 -104 105 1 -4.49 -1 104 -105 106 1 -4.49 -1 105 -106 107 1 -4.49 -1 106 -107 108 1 -4.49 -1 107 -108 109 1 -4.49 -1 108 -109 110 1 -4.49 -1 109 -110 2 2 -0.9982 1 15 3 3 -1.2 1E-03 15 -2 4 4 -7.94 2 16 7 5 -2.3 5 -4 8 5 -2.3 -14 12 9 5 -2.3 -9 8 7 -19 9 1 5 -2.3 -91 81 19 -20 10 5 -2.3 7 11 3 -1.21E-03

-8 12 3 -1.21E-03

-6 7 -11 9 #18 #19 #91 1 3 3 -1.2 1E-0 3 -1 3 3 #91 14 3 -1.2 1E-03 -17 15 4 -7.94 2 -18 16 4 -7.94 6 11 17 4 -7.94 1 3 -12 18 4 -7.94 -82 19 4 -7.94 -92 9 99 0 1 #2 #3 #4 #7 #8 #9 #15 #16 #17 Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levelsi----

---

1 During Refueling for EAL Thresholds REV. 00 Figure 5 MCNP Model Cell Cards (No Head) imp:p=256 $ Active Fue l Regi o n imp: p=128 $ Active Fuel Region imp: p=64 $ Active Fuel Regi o n imp: p=32 $ Active Fuel Region imp: p=l6 $ Active Fuel Region imp: p=8 $ Active Fuel Region imp: p=4 $ Active Fuel Region imp: p=3 $ Active Fuel Regi o n i mp: p=2 $ Active Fuel Region imp: p=l $ Active Fuel Region imp:p=256 $ Water Region imp:p=256 $ Air Regio n inside vesse l imp:p=256 $ RPV She11 imp:p=256

$ Concrete Surrounding RPV spherical imp:p=2 56 $ Con c rete Surrounding RPV cylindri c al imp:p=2 56 $ Pedestal imp:p=256

$ Bio Shield imp:p=2 56 $ C o ncrete at b o ttom of pedestal imp:p=2 56 $ Inside Pedestal Air 3 imp:p=256 $ Inside Spherical portion Air i mp:p=256 $ In side Cylindrical portion Air imp:p=256

$ Reactor B u ilding above drywell Air imp:p=256

$ Reactor B u ild Roof Stainless Steel imp:p=256 $ Containment Liner Spher i cal portion imp: p=256 $ Containment Liner Cylin portion imp:p=256

$ Recirc Pump IP-201A imp:p=256

$ Recirc Pump IP-201B #10 #11 #12 #13 #14 #18 #19 #91 imp:p=O $ Problem Boundary Page 22 of 28 Dose Rate Evaluation of CALC NO. _. ENERCON Reactor Vessel Water Levels

• During Refueling for EAL Excellence

-Every p roject. E*e,y day. REV. Thresholds Figu re 6 X-Z V SEO Plot of Reactor Vessel (With Head) N EE-323-CALC-002 00 Reactor Vessel H ead Cell for the homogenization of the Upper Internals stainless steel 0.379 g/cm 3 7 .5 MCNP Source Definition Homogenized Core The core source term is modeled as uniformly distributed throughout the homogenized core, and has an energy spectra based on the decayed core inventory (Section 7.1 ). Only the gamma source term is taken into account for this evaluation.

The source term is generated shortly after shutdown, therefore , the fuel gamma source term will predominate , and the neutron-gamma and hardware activation source terms can be neglected (Assumption 4.7). The source is defined on the MCNP sdef card using Page 23 of 28 Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels _____________

-; ENERCON Exce ll ence-E very p ro1 ecr. E*ery da y. During Refueling for EAL Thresholds REV. 00 distributions to define the particle location and energy. The radius of the core is defined with the rad parameter, which automatically creates a uniform distribution based on a cylindrical geometry.

The ext and axs parameters define the direction and distance of the cylinder axis. These parameters combined define the core where the particles can be born. The e r g parameter defines the energy spectrum of source particles , and is based on the results of the ORIGEN-S calculation discussed previously.

This distribution is a histogram of energies represented by activities.

These are automatically normalized by MCNP to c r eate a probability distribution.

The total activity is preserved in the tally multiplier.

The MCNP source definition cards are shown below in Figure 7. The sb card is a source biasing card , which in this case biases the particle generation to the lower end of the core. This is a variance reduction technique to improve the statistical certainty in the results. Figure 7 MCNP Source Definition Cards sdef rad=dl e x t=d 2 a xs=O O 1 erg=dB sil 137.045 si2 h O 742.546 779.122 815.698 852.274 888.85 925.246 962.002 998.578 10 35.154 1071.73 sp2 0 1 1 1 1 1 1 1 1 1 1 sb2 0 1 1 0.1 0.1 0.1 0.01 0.01 0.01 0.00 1 0.001 c Fuel Gamma Spectra ~Source Definition Card -Radius= dl -Extent= d2 -Axis= +Z -Energy= dB ~Core Radius Distribution

~Core Axial Distribution

~Actual Uniform Distribution

~Biased to Bot Distribution siB h l.OOOe-002 5.000e-00 2 l.OOOe-001 2.000e-001 3.000e-001 4.000e-001 ~Source Energy Groups 6.000e-001 8.000e-001 1.000e+OOO 1.330e+OOO 1.660e+OOO 2.000e+OOO 2.500e+OOO 3.000e+OOO 4.000e+OOO 5.000e+OOO 6.500e+OOO 8.000e+OOO 1.000e+OOl 1.lOOe+OOl sp8 0.00E+OO 2.028E+19 6.572E+18 1.557E+19 9.672E+18 3.582E+18 7.837E+18 ~Source Emission on Energy Basis 1.373E+19 2.132E+18 4.942E+17 3.579E+18 6.576E+16 7.518E+16 l.110E+17 8.689E+14 l.553E+10 2.568 E+0 8 3.792E+07 8.041E+06 4.352E+05 Page 24 of 28 Dose Rate Evaluation of CALC NO. N EE-323-CALC-002 Reactor Vessel Water Levels f-----------------1

• ENERCON Exce lle nu-E v t!ry p r o j ect. Every d ay. During Refueling for EAL Thresholds 7.6 MCNP Tally Specification REV. 00 The tallies used in this evaluation are point detectors placed at approximate locations of radiation monitors RE-9184A, and RE-91848. Point detectors are chosen because they use quasi-deterministic dose calculations that will provide better results than surface or cell based tallies that r equire the particles to enter those regions. The inputs to this card are the coordinates of the dose points followed by an exclusion zone to reduce variance, as well as a multiplier card, which represents the total core activity in photons/sec. The tally cards are shown in Figure 8. Figure 8 MCNP Tally Cards f5c RE-9184A , and 9184B f5: p -121.92 406.29 -1 84.15 20 182.88 -365.76 -184.15 20 fm5 8.370E+l9

~T ally Comment Card ~Tally 5 (point dete c tor) x y z exclusion Tally Multiplier (Total Activity)

In addition , the flux is multiplied by ANSI/ANS flux-dose conversion factors [Reference 3.4]. This is specified in MCNP using the de/df cards. These are shown in Figure 9. Figure 9 ANSIIANS-6. 1.1-1977 Gamma Flu x to Dose Conversion Factors C -------------------------------------

---

C ANSI/ANS-6

.1.1-1977 c Gamma Fl ux to Dose Conversion Factors c (mre m/hr)/(photons/cm2-s) C ------------------------------------------------------------------

deO .0 1 .03 .05 .07 .10 .15 .20 .2 5 .30 .35 .40 .45 .5 0 .55 .60 .65 .70 .80 1. 1.4 1.8 2.2 2.6 2.8 3.25 3.75 4.25 4.75 5. 5.25 5.75 6.25 6.75 7.5 9. 11. dfO 3.9 6 E-03 5.82E-04 2.90 E-04 2.58E-04 2.83E-04 5.0lE-04 6.31E-04 7.5 9E-04 8.78E-04 9.85E-04 l.1 7E-03 1. 27E-03 l.36E-03 l.4 4E-03 l.52E-03 l.9 8E-03 2.5 1E-03 2.99E-03 3.42E-03 3.82E-03 4.41E-03 4.83E-03 5.23E-03 5.60E-03 5.SOE-03 6.37E-03 6.74E-0 3 7. llE-03 7.66E-03 8.77E-03 Page 25 of 28 3.79 E-04 l.08E-0 3 l.68E-03 4.0lE-03 6.0lE-0 3 l.03E-02 ~Energy Bins for Flu x to Dose Conversion

~Energy Dependent F lu x Multipliers ENERCON Exce ll ence-Every p r o j ecr. f*e,y d ay. Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels,___

___________ -----< During Refueling for EAL Thresholds REV. 00 7.7 MCNP Material Cards The MCNP material cards are provided in Figure 9. These are based on the compositions described in Table 6 or calculated in Section 7.2. ml m2 m3 m4 m5 m6 92235 -0.0253 92238 -0.6163 8016 -0 .1896 40000 -0.1531 50000 -0.0023 24000 -0.0002 26000 -0.0003 1001 -0.0129 1001 2 8016 1 6012 -0.000126 70 1 4 -0.76508 8016 -0.234793 6000 -0.0008 14000 -0.01 15031 -0.00045 24000 -0.19 25055 -0.02 26000 -0.68375 28000 -0.095 26000 -0.014 1 00 1 -0.0 1 1 3027 -0.034 20000 -0.044 80 1 6 -0.532 14000 -0.337 11023 -0. 029 6012 -0.01 26056 -0.99 Figure 10 MCNP Material Cards $ Homogenized Active Fuel Region $ Water $ Air $ ss 304 $ Reg-Concrete $ Carbon Steel Page 26 of 28 Dose Rate E v aluatio n of CALC NO. NEE-323-C A L C-0 02 Reactor Vessel Water Le v els>--___________ _____, ENERCON Excellence-Every proiect. E*ery day. 7.8 R esults During Refueling for E A L Thresholds REV. 00 The dose rates are provided in Tab l e 10 for the water l eve l at the top o f the fue l assemblies.

The dose rate is slightly above the detectable response of 1 R/h (1 E+03 mrem/h) for the no head configuration, and be l ow the detectable respo n se for t h e configurat i on with the reactor vessel head in place for one of the detectors.

T h e sensit ivi ty case shows that there is no significant impact due to reflection from the drywell cap. Table 10 -Dose Rate Response (mremlh) Co nfi g ur at ion D ose R a t e 1 fs d 6 Do se R a te 2 fs d T a ll y Fil e RE-9 184 A RE-9184B No H ea d 1.81 E+03 10.81% 1.68 E+03 7.3 1% dOndm With Hea d l.l 1 E+03 10.1 6% 7.41 E+0 2 8.24% dOh g m With Head (S e n-l.07 E+03 15.2 7% 7.67 E+0 2 1 5.51% dOrdm sitivi Ca s e 8.0 Computer Software This calculation uses ORIGEN-S of the SCALE Version 6.1.2 code package [Reference 3.2] and MCNP Version 6.1.0 [Reference 3.3] in accordance with CSP 3.09. 6 Fracti o n standard d e v iation. Page 27 of 28 ENERCON Excellence-Every pro1ecr. Every day. 9.0 Impact Assessment Dose Rate Evaluation of CALC NO. NEE-323-CALC-002 Reactor Vessel Water Levels ,____ ___________

---. During Refueling for EAL Thresholds REV. 00 This calculation is based on " realistic" assumptions fo r the purpose of declaring EALs , rather than typical conservative

" bounding" type design basis analyses.

The calculation results are intended to provide order of magnitude dose rates to assist Operations and Emergency Response personnel in determination of core uncovery in accordance with NEI 99-01 Rev. 6. Page 28 of 28 J I ENERCON Excellence-Every project. Every day. Origen output: 07/26/2017 04: 19 PM MCNP o u t p ut: Directory of \No head\ 08/16/2017 09: 13 AM Directory of \With Head\ 08/16/2017 10: 01 AM Directory of \sensitivity\

08/16/2017 03: 54 AM CALC N EE-323-CALC-002 Appendi x A NO. E l e ctronic File Li sting REV. 00 82 , 114 DAECEAL.OUT 327 , 680 dOnao 1 , 269 , 760 dOhgo 286 , 720 dOrdo Page 1 of 1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 1 8 19 20 21 22 23 24 25 26 27 28 29 30 31 ENERCON Excellence-Every project Everyday; A B C D Weight Material Isotope Fraction Zry-4 Zr 0.98 23 (6.5 6 'lf cm.3) Sn 0.0 1 4 5 Cr 0.001 Fe 0.002 1 Hf 0.000 1 U0 2 U-23 5 0.0 3 4 8 U-23 8 0.8 4 66 0 0.118 6 Air C 0.000 1 (1.21 E--0 3 N 0.7 651 g/cm.3) 0 0.234 8 Water H 0.1111 (0.998 2 'lf cm.3) 0 0.8889 SS-304 Fe 0.6838 (7.9 4 g/cm.3) Cr 0.19 Ni 0.0 95 Mn 0.02 S i 0.01 C 0.000 8 p 0.0004 Concrete 0 0.53 2 (2.3 0 g/cm.3) S i 0.33 7 Ca 0.044 Al 0.034 N a 0.02 9 Fe 0.0 1 4 H 0.0 1 Carbon Steel C 0.0 1 (7.82 g/cm 3) Fe 0.99 CA LC N EE-323:-C A LC-002 Appendix B NO. DAE AL.xlsx Sheets RE V. 00 E F G H K L Mas Reference Materials (KG) ZAIDNumber Mass Fraction Active fuel Atom Region Homogenized

[1] U0 2 2 00.4 92235 U-235 0.0253 Zry-4 4 2.9 2 92238 U-238 0.6 1 63 Water 31.98 80 1 6 0 0.1 896 4 0000 Zr 0.1531 --+ 50000 S n 0.0023 .. -+ [1] t 24000 Cr 0.0002 26000 F e 0.0003 + + nooo H f 0.000 0 +-+ [1] --+ ----~ *-~ 1 00 1 H O.OU 9 1.000 0 + + *-; + [1] +-+ + + [1] -+ + --~ _,_ ~----l-* + .... +-+ t + + t [1] I .. t [1] Page 1 of 2 1 2 3 4 5 6 7 8 9 1 0 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 3 1 A ------. I :ti B Material Zry-4 (6.5 6 g/cm.3) U 0 2 Air (U IB-03 g/cm 3) Water (0.998 2 gt cm.3) SS-304 (7.9 4 g/cm 3) Concrete (2.30 gl cm 3) Carbon Steel (7.8 2 g/crr i.3) ENERCON Ex c ellence-E v try p roject. £v ery day. C D E Isotope Weight Reference Fraction Zr 0.98 2 3 [l] S n 0.0 1 45 C r 0.00 1 Fe 0.0021 Hf 0.000 1 U-23 5 0.034 8 [l] U-23 8 0.8 466 0 0.11 8 6 C 0.0001 [1 1 N 0.7 65 1 0 0.234 8 H 0.11 11 [l l 0 0.8889 Fe 0.6 S 3 8 [1] C r 0.19 N i 0.0 9 5 Mn 0.02 S i 0.0 1 C 0.000 8 p 0.0004 0 0.53 2 Ul Si 0.337 Ca 0.044 Al 0.034 N a 0.02 9 Fe 0.0 1 4 H 0.0 1 C o.oi [l] Fe 0.99 CALC N EE-323-CALC-002 Appendix B NO. DAEAL.xlsx Sheets RE V. 00 F G H K L ZAID Material Mass (KG) Number Atom Ma ss Fraction Act i ve Fue l Region Homogenized U0 1 200.42 92235 U-235 =(H 3/S UM(H 3:H 5))*08 Zry-4 42.9 2 92238 U-238 =(H 3/S UM(H 3:H 5))"D 9 Water 3 1.98 . 80 1 6 0 =((H 3/(S UM(H 3:H 5)))"'D10)+((H 5/(S UM(H3:H 5))))*0 15 4 0000 Zr =($H$4/S UM($H$3:.$H$5))"'D3 50 000 S n =($H$4/S UM($H$3:$H$5))"'04 2 4 00 0 Cr =($H$4/S UM($H$3:$H$5))"'D5 26000 F e =($H$4/S UM($H$3:$H$5))"'06 72 000 H f =($H$4/S UM($H$3:$H$5))"'D 7 1 0 01 H =(H 5/S UM(H 3:H 5))"'D l4 =S UM(L3:Ul) -*--*-+--. Page 2 o f 2

.. ENERCON Appendix C SCALE Input CALC NO. Excellence-Every projecl. Every day. REV. =o rigens 0$$ all 71 e t BWR Source T erm DAEC EAL Analysis 3$$ 21 1 1 a4 27 a16 4 a33 19 et 35$$ 0 t 54$$ as o all 2 e 56$$ 0 6 a6 1 alO O a13 63 3 3 0 2 0 e 57** 0 a3 1-16 e 95$$ 0 t DAECEAL Ci Source Terms 60** 0 24 40 50 60 70 61** 5rl-8 1+6 1+4 65$$ 'GRAM-ATOMS GRAMS CURIES WATTS-ALL WATTS-GAMMA 3Z 0 1 0 1 0 0 1 0 0 3Z 6Z 3Z 1 1 1 1 0 1 1 1 1 3Z 6Z 3Z 1 1 1 1 1 1 1 1 1 3Z 6Z 81$$ 2 0 26 1 e 82$$ f2 83** l.10E+07 1. OOE+07 8.00E+06 6.50E+06 5.00E+06 4.00E+06 3.00E+06 2.50E+06 2.00E+06 l.66E+06 l.33E+06 1. OOE+06 8.00E+05 6.00E+05 4.00E+05 3.00E+05 2.00E+05 1.00E+05 5.00E+04 l.OOE+04 e 84** 2.00E+07 6.43E+06 3.00E+06 l.85E+06 1.40E+06 9.00E+05 4.00E+05 1. OOE+05 1.70E+04 3.0 0E+03 5.50E+02 1.00E+02 3.00E+Ol 1.00E+Ol 3.05E+OO 1.77E+OO 1.30E+OO 1.13E+OO 1.00E+OO 8.00E-01 4.00E-01 3.25E-01 2.25E-01 1.0 0E-01 5.00E-02 3.00E-0 2 1.00E-02 1.00E-0 5 e 73$$ 56 1390 561400 581410 581430 581440 962420 551340 551360 551370 531310 531320 531330 531340 531350 360831 360850 360851 360870 360880 571400 571410 571420 420990 410950 601470 932390 591430 942410 370860 451050 441030 441050 441060 511270 511290 380890 380900 380910 380920 430991 521270 521271 521290 521291 521311 521320 541311 541330 541331 541350 541351 541380 390900 390910 390920 390930 400950 400970 74** 9.06E+07 9.10E+07 8.39E+07 7.65E+07 6.77E+07 2.14E+06 8.99E+06 2.85E+06 6.21E+06 5.11E+07 7.42E+07 l.04E+08 1.14E+08 9.90E+07 5.83E+0 6 5.32E+05 l.18E+07 2.35E+07 3.25E+07 9.39E+07 8.28E+07 8.05E+07 1. OlE+OS 8.60E+07 3.35E+07 1.09E+09 7.57E+07 8.15E+06 l.01E+05 5.37E+07 8.30E+07 5.85E+07 2. 96E+07 4.57E+07 1.66E+07 4.61E+07 4.57E+06 5.76E+07 6.19E+07 8.36E+07 4.51E+06 7.59E+05 1.58E+07 3.21E+06 l.0 3E+07 7.28E+07 6.98E+05 1. 04E+08 3.29E+06 2. 72E+07 2.20E+07 8. 72E+07 4.68E+07 6.06E+07 6.23E+07 4.82E+07 8.49E+07 8.09E+07 75$$ 3 3 3 3 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 2 3 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 t 56$$ fO t end Page 1 of 1 3 N EE-323-CALC-002 00 CALC NEE-323-CALC-002 Attachment 1 NO. II. ENERCON CALCULATIO N P REPARAT I ON

• CHECKLIST Exceflenc~-Every pro j ecr. £very day. REV. 0 CHECKLIST ITEMS 1 YES NO N/A GENERAL REQUIREME N TS 1. If the c a lcul a tion is being p e rformed to a cl i ent proc e dure , is the procedure being D D rgJ used the latest revision?

The C a l c ulation is performed in ac c o r dance with ENERCON procedures. 2. Are the prope r forms being used and are they the l atest revision?

rgJ D D Th e Calcu l ation is performed in accordance with ENERCON procedures. 3. Have the appropriate client review forms/ch e cklists been completed?

D D rgJ OAR will be perform e d after calculation submittal

4. Are all p a g e s properly id e ntifi e d with a calculation number , calculation revision and rgJ D D page num be r consistent w i th the requirem e nts of the client's procedu r e? 5. Is all info r m a tion legible and reproducible?

rgJ D D 6. Is the calcul a tion presen te d in a logical and orderly manner? rgJ D D 7. Is there an existing calculation that should be revised or voided? D rgJ D There is no existing ca l c ul ati o n that should be revised o r v oided. 8. Is it possible to a l ter an existing ca l culation instead of preparing a new ca l culation for D rgJ D this situation?

No ex i sting calculation would be applicable.

9. If an exist i ng calculation is being used for design inputs , are the key design inputs , assumptions and enginee r ing judgments used in that calculation valid and do they D D rgJ apply to the calculation revision being performed. No existing calculat i on is used for design inputs 10. Is the format of the ca l culation cons i stent with app l icable procedures and rgJ D D expectations?

11. Were design input/output documents properly updated to reference this ca l cu l ation? D D rgJ There are no design output documents. 12. Can the calculation logic , methodology and presentat i on be properly understood rgJ D D without referring back to the originator for clarification?

OBJECT IV E A N D SCOPE 13. Does the calcu l ation provide a clear concise statement of the prob l em and objecti v e rgJ D D of t h e calculation?

14. Does the calculati o n provide a clear statement of qua l ity classification?

rgJ D D 15. I s the reason for perf o rming and the end use of t he calculation u n derstood?

rgJ D D 1 6. Does the calculation provide the basis for informat i on found in the plant's license D rgJ D basis? This does n o t provide basis for license basis 17. I f s o , is this documented in the ca l c ul ation? D D rgJ Page 1 of 5 CALC N EE-323-CA L C-0 02 Attac h ment 1 NO. ENERCON CALCULATION PREPARATION

• CHECKLIST Exce//ence-E~ry project. Every doy. REV. 0 CHECKLIST ITEMS 1 YES NO N/A See above 18. Does the calculat i on provide the bas i s for information found in the plant's design D D 1:8:J basis documentation?

This does not provide basis for design bas i s 19. If so, is this documented in the ca l culation?

D D 1:8:J See above 20. Does the calculation otherwise support information found in the p l ant's design basis D 1:8:J D doc u mentation?

This does not provide support for information found in design basis documentation

21. If so , is this documented in the calculation?

D D 1:8:J See above 22. Has the appropriate design or license basis documentation been revised , or has the D D 1:8:J change notice or change request documents being prepared for submittal?

See above DESIGN INPUTS 23. Are design inputs clearly identified?

1:8:J D D 24. Are design inputs retrievable or have they been added as attachments?

1:8:J D D 25. If Attachments are used as design inputs or assumptions are the Attachments 1:8:J D D traceable and verifiable?

26. Are des i gn inputs clearly distinguished from assumptions?

1:8:J D D 27. Does the calculation rely on Attachments for design inputs or assumptions?

If yes , 1:8:J D D are the attachments properly referenced in the calculation?

The Design I nformation Transmittal is included as an Attachment is proper l y referenced in the calculat i on 28. Are i nput sources (including indus t ry codes and standards) appropriately selecte d 1:8:J D D and are they consistent with the qua l ity classification and objective of the ca l cu l ati o n? 29. Are input sources (i ncluding industry codes and standards) consistent with the plant's 1:8:J D D desig n and license b asis? 30. If app l icable , do des i gn inputs adequately address actual plant conditions?

1:8:J D D 31. Are input values reasonable and correctly app l ied? 1:8:J D D 32. Are d esign input s ourc es approved?

1:8:J D D The Desig n I nformation Tran s mittal contains information from a superseded calculation. 33. Does the calcu l ation reference the latest revision of the design inp u t source? 1:8:J D D The calcu l at i on uses information from a superseded calculation. This information is provided in a Design I nformation Transmitta

l. 34. Were all app l icab l e p l ant operating m o des considered?

1:8:J D D ASSUMPTIONS Pa g e 2 of 5 CALC NEE-323-CALC-002 Attachment 1 NO. .. ENERCON CALCULATIO N PREPARATION Excellence-Every pro/ecr. Every doy. CHECKLIST REV. 0 CHECK LI ST ITEMS 1 YES NO N/A 35. Are assumptions reasonable/appropriate to the objective? D D 36. Is adequate justification/basis for all assumptions provided? D D 37. Are any engineering judgments used? D D Engineering judgement not used as design input. 38. Are engineering judgments clearly identified as such? D D Engineering Judgement is not used as a design input. 39. If engineering judgments are utilized as design inputs , are they reasonable and can they be quantified or substantiated by reference to site or industry standards , D D engineering principles , physical laws or other appropriate criteria?

Engineering Judgement is not used as a design input. METHODOLOGY

40. Is the methodology used in the calculation described or implied in the plant's D D licensing basis? The scope of calculation is outside of plant l icensing basis 41. If the methodology used differs from that described in the plant's l i censing basis, has D D the a ppropriate l icense document change notice been initiated?

see above. 42. Is the methodology used consistent with the stated objective? D D 43. Is the methodology used appropriate when cons i dering the quality classification of D D the ca l culation and intended use of t h e resu l ts? BODY O F C AL C U LAT ION 44. Are equations used in the calculation consistent with recognized engineering practice D D a n d the plant's design and license b asis? 45. I s t h ere reasonab l e justification pro vid ed for the use of equations n ot in common D D use? There are n o uncommon equations used in the calculation. 46. Are the mathematical operations performed properly and documented in a logical D D fash i on? 47. Is the math performed correctly? D D 48. Ha v e adjustment fact o rs, uncertainties and empirical correlati o ns used in the ana l ysis D D been co rrectly app l ie d? 49. Has p ro per cons i deration been gi v en t o resu l ts that may be o v er l y s ensiti v e to very D D sm a ll c h anges in in put? S O FT WAR E/COMPU TER COD ES 50. Are computer codes or software languages used in the preparation of the D D ca l culation?

MCNP a nd Sca l e are used Page 3 of 5 CALC NEE-323-CALC-002 Attachment 1 NO. E NERCON CALCULATION PREPARATION 1 CHECKLIST Exce l lence-Evtry projecr. Every day. REV. 0 CHECKLIST ITEMS 1 YES NO N/A 51. Have the requirements of CSP 3.09 for use of compute r codes or software 18] D D languages , including verification of accuracy and applicability been met? 52. Are the codes properly identified along with source vendor , organization , and revision 18] D D level? 53. Is the computer code applicable for the analysis being performed?

18] D D 54. If applicable , does the computer model adequat e ly consider actual plant conditions?

18] D D 55. Are the inputs to the computer code clearly identified and consistent with the inputs 18] D D and assumptions documented in the calculation?

56. Is the computer output clearly identified?

18] D D 57. Does the computer output clearly identify the appropriate units? 18] D D 58. Are the computer outputs reasonable when compared to the inputs and what was 18] D D expected?

59. Was the computer output reviewed for ERROR or WARNING messages that could 18] D D invalidate the results? RESULTS AND CONCLUSIONS

60. Is adequate acceptance criteria specified?

D D 18] There is no acceptance criteria as discussed in calc. 61. Are the stated acceptance criteria consistent with the purpose of the calculation , and D D 18] intended use? See above 62. Are the stated acceptance criteria consistent with the plant's design basis, applicable D D 18] licensing commitments and industry codes , and standards?

See above 63. Do the calculation results and conclusions meet the stated acceptance criteria?

D D 18] See above. 64. Are the results represented in the proper units with an appropriate tolerance , if 18] D D applicable?

65. Are the calculation results and conclusions reasonable when considered against the 18] D D stated inputs and objectives?

66. Is sufficient conservatism applied to the outputs and conclusions?

18] D D Page 4 of 5 CALC NEE-323-CALC-002 Attachment 1 NO. ENERCON CALCULATION PREPARATION

't CHECKLIST Excellen c e-Every pro j ect. Every do y. REV. 0 CHECKLIST ITEMS 1 YES NO NIA 67. Do th e calculat i on result s and conclusions affect any other ca l cu l ations? D D No other ca l cu l ations are affected by this calculation. 68. If so , have the affected calculations been revised? D D No other calcu l ations are affected by this ca l culation. 69. Does the calculation contain any conceptual , unconfirmed or open assumptions D D requiring later confirmation?

There are no op e n assumptions requiring confirmation l ater. 70. If so , are they proper l y i dentified?

D D There are no open assumptions requiring confirmation l ater. DESIGN REVIEW 71. Have alternate c a l cu l ation methods been us e d to ver i fy calculat i on results? D D No a Design Review was performed. Note: 1. Where requi r ed , pro v ide cla ri fication/justification for answe r s to the questions in the space pro v ided below each question. An explanation is required for any questions answered as " No' or " N/A". Originator:

Jay Bhatt Print Name and Sign Date Page 5 of 5