ML101300237
| ML101300237 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 05/07/2010 |
| From: | Sokolsky D PG&E Corp |
| To: | John Hickman NRC/FSME/DWMEP/DURLD/RDB |
| References | |
| TAC J00368 NX-356, Rev 00 | |
| Download: ML101300237 (75) | |
Text
{{#Wiki_filter:Hickman, John From: Sokolsky, David [DDS2@PGE.COM] Sent: Friday, May 07, 2010 2:21 PM To: Hickman, John
Subject:
HBPP CALC NX-356 Attachments: 20100507103717.pdf John - Per your request David Sokolsky Supervisor of Licensing Humboldt Bay Power Plant (707)444-0801 office (707)601-6703 cell 1
Sheet 1 of ZL HUMBOLDT BAY POWER PLANT CALCULATION COVER SHEET Unit/ISFSI: 3 Calculation No. NX--36-5% 2Sp Rev. 66) FD Preliminary Z Final Plant Problem Report: 1252513 Type or Purpose of Calculation: Radiological Consequences for Breach of Defueled Spent Fuel Pool, June 2009 I Structure, System, or Component: I Unit 3 Spent Fuel Pool I Department/Group: RP No. of .Total [7'1] = Cover and Rec of Revs [ J + body [; J + attach. [l ] Sheets: Name / Signature Discipline / Date Dept Prepared by: ISCs (se. +&e Cog~c-~r ' (31o9 Checked by: D.141 c1 -*:f" Approved by: , A___ ,, II e__,_ __,,,__ Concurrence for Checker: [ N/A Signature Date RP CALCULATIONS Desianated RP Approver: , /f% re Print Name RPManager: (-'
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RADIATION SAFETY & CONTROL SERVICES, INC. Technical Support Document TSD # 09-020 Humboldt Bay Power Plant Unit 3, Radiological Consequences for Breach'of Defueled Spent Fuel Pool Revision 00 Originator: Harvey Farr Date: May 28, 2009 Reviewer: Date: June 3. 2009 Eric L.'Tfarois, CHP Approval:. r Fro twaccla, CHF 9V Date: June 3, 2009
TSD # 09-020 Revision 00 Page 2 of 73 Humboldt Bay Power Plant Unit 3, Radiological Consequences for Breach of Defueled Spent Fuel Pool 1.0 Introduction This document evaluates the consequences of a heavy load drop in the spent fuel pool after the fuel has been removed. The consequences of a heavy load drop were previously evaluated for the SAFSTOR Safety Evaluation Report (Ref. 7.17, 7.18) and for the Independent Spent Fuel Storage Installation Safety Evaluation Report.(Ref. 7.19) These evaluations concluded that the only potential consequence from a heavy load drop was contamination of subsurface groundwater and subsequent release of radionuclides to Humboldt Bay. Operating procedures to prevent the movement of Heavy Loads over the Spent Fuel Pool were implemented to reduce the probability of a heavy load drop in the Spent Fuel Pool. The spent fuel has since been removed and placed in dry cask storage. This evaluation examines the radiological impact of a heavy load drop on the Spent Fuel Pool, in the defueled condition, to support determination if restrictions on the transport of heavy loads over the Spent Fuel Pool are still required. This document calculates the current dispersible radionuclide inventory of the spent fuel pool which could be released in a heavy load drop and uses RESRAD-OFFSITE with site specific hydrogeological data to evaluate the radiological consequences of a heavy load drop in the Spent Fuel Pool. 2.0 Table of Contents 1.0 Introd uctio n ............................................................................................................................... 2 2 .0 Table of Contents ...................................................................................................................... 2 3 .0 Backg ro und ............................................................................................................................... 4 3.1 Regulatory Requirements for Decommissioning Safety Evaluations ................................... 4 3.2 P revious Evaluations ............................................................................................................. I... 7 3.3 RESRAD-OFFSITE ........................................................................................................... 8 4.0 Evaluation and Calculations .................................................................................................. 9 4.1 S pent Fuel Pool Structure ...................................................................................................... 9 4.2 Spent Fuel Pool Volume and Source Term ......................................................................... 14 4.3 Heavy Load Drop Scenario On-Site Consequences ........................................................... 18 4.4 Stratigraphy and Aquifers Underlying Unit 3 ....................................................................... 18 4.5 Water Table Depths and Aquifer Gradients ......................................................................... 24 4 .6 Hum boldt B ay ............................................... ......................................................................... 28 4.7 Postulated Release to Groundwater ................................................................................... 29 4.8 RESRAD-OFFSITE Model of Release ................................................................................ 31
TSD # 09-020 Revision 00 Page 3 of 73 4.9 Fish Pathway Model ................................................................................................................ 35 4.10 Saturated Zone Distribution Coefficients for Americium, Plutonium, and Curium ................ 40 4.10.1 Am ericium ............................................................................................................................... 40 4.10.2 Curium ................................................................................................................................... 43 4.10.3 Plutonium ................................................................................................................................ 45 4.11 Calculated Pathway Annual Doses .................................................................................... 46 4.12 Groundwater Concentrations Released to the Bay .............................................................. 48 4.13 Drinking W ater Pathway .................................................................................................... 49 4.14 Potential Impact on Decom missioning .......... . ......... . ... ..................................... 51 5.0 Conclusion ............................................................................................................................... 52 6.0 Attachm ents ............................................................................................................................ 53 6.1 Attachment A - Map of ISFSI and Unit 3 Site Area Showing Geological Borings and Monitoring W ells ...................................................................................................................................... 53 6.2 Attachment B - Buhne Point Geological Strata and Aquifers ........................... 53 6.3 Attachment C - Upper Hookton Groundwater Contours at MLLW ...................................... 53 6.4 Attachment D - RESRAD-OFFSITE Input parameters ....................................................... 53 7.0 References ............................................................................................................................. 53
TSD # 09-020 Revision 00 Page 4 of 73
3.0 Background
3.1 Regulatory Requirements for Decommissioning Safety Evaluations On July 29, 1996, a final rule amending the regulations on decommissioning procedures was published in the Federal Register (61 FR 39278). Regulatory Guide 1.184 describes methods and procedures for power reactor licensees for the decommissioning process.(Ref. 7.3) The 1996 rule extended the use of 10 CFR 50.59, "Changes, Tests, and Experiments," to allow licensees to make changes to facilities undergoing decommissioning using the process described in 10 CFR 50.59.(Ref. 7.3) The Post-Shutdown Decommissioning Activities Report (PSDAR) evaluates the environmental impacts associated with the site-specific decommissioning activities. If environmental impacts are identified that have not been considered in existing environmental assessments, the "Final Generic Environmental Impact Statement (GElS) on Decommissioning of Nuclear Facilities" (NUREG-0586, Ref. 7.7), and the GELS, "Generic Environmental Impact Statement in Support of Rulemaking on Radiological Criteria for License Termination of NRC Licensed Nuclear Facilities" (NUREG-1496, Ref. 7.9), the licensee must address the environmental impacts regarding the activities and must submit a supplement to the environmental report relating to the additional impacts.(Ref. 7.3, 7.4) Regulatory Guide 1.185, "Standard Format and Content for Post-shutdown Decommissioning Activities Report" (Ref. 7.4), provides guidance on the contents of the PSDAR. The PSDAR should include a discussion of the reasons for concluding that the environmental impacts associated with site-specific decommissioning activities will be bounded by previously issued environmental impact statements. The potential environmental impacts associated with decommissioning should be compared with similar impacts given in the Final Environmental Statement (FES) for the plant (as supplemented), in the GElS on decommissioning (NUREG-0586) (Ref. 7.7), site-specific environmental assessments, and the GElS on radiological criteria for license termination (NUREG-1496) (Ref. 7.9). Examples of potential impacts that should be examined to ensure they are within the envelope of impacts predicted in the GEISs on decommissioning or radiological criteria for license termination, FES, or site-specific analysis include occupational dose; environmental releases to air, water, and soil and the resulting population doses; .(Ref. 7.4) Changes in decommissioning activities should be evaluated as to their potential environmental impact. Ifthe expected impact is greater than that predicted in the GEIS or the site-specific FES, or is outside the bounds of these documents, the licensee must notify the NRC in writing and provide a supplement to the Environmental Report for the facility that evaluates the impact of the change.(Ref. 7.4) The Final Safety Analysis Report (FSAR), or other comparable document, provides a licensing basis document for the evaluation of licensee activities under 10 CFR 50.59. This licensing basis is updated to cover decommissioning activities. According to 10 CFR 50.71(e)(4), subsequent revisions updating the licensing basis must be filed with the NRC at least every 24 months by nuclear power facilities that have submitted certifications for permanently ceasing operations and for permanent removal of fuel.(Ref. 7.3) As a minimum, the FSAR should be maintained at a level of detail that provides status of all the operating licensing-basis systems, structures and components (SSCs) until the systems are no longer mechanically or electrically active, no longer radioactively contaminated, have no fluid content or other materials that
TSD # 09-020 Revision 00 Page 5 of 73 require special handling considerations, or have been physically removed during the dismantlement process.(Ref. 7.3) Decommissioning Facilities are-typically bounded by the Generic Environmental Impact Statement (NUREG-0586).(Ref. 7.8) Volume 1, Supplement 1 of NUREG 0586 states, "This document can be considereda stand-alone document for power reactorfacilities such that readersshould not need to refer back to the 1988 GEIS.(Ref. 7.8) Section 4.3.9 Radiological Accidents reiterates the applicable regulations pertaining to evaluation of accidents, "Regulationsgoveming accidents that must be addressedby nuclearpower facilities, both operating and shutdown, are found in 10 CFR Part50 and 10 CFR Part 100."(Ref. 7.8) Section 4.3.9 of the GElS refers to the various types of accidents that may be of significance during decommissioning "fuel removal, organizationalchanges, stabilization,chemical decontamination,large component removal, decontaminationand dismantlement, system dismantlement, entombment, and transportationare activities that may lead to radiological accidents.Many activities that occur during decommissioning are similar to activities, such as decontaminationand equipment removal that commonly take place during maintenance outages at operatingplants. However, during decommissioning such activities may be more extensive than similaractivities during the period of reactoroperations.Consequently, potential accidents associatedwith these activities may have a higherprobabilityduring decommissioning than when the plant is operating.Accidents that occurduring these activities may result in injury and local contamination;they are not likely to result in contamination offsite. Section 4.3.9 of the GElS focuses on spent fuel accidents as the generically bounding. accident for decommissioning facilities. The GElS states, "Once the reactorfuel has been moved to the spent fuel pool, the only DBAs containedin the plant'sFSAR that are applicable are those associatedwith the spent fuel pool. These accidents are generally relatedto fuel handling or dropping heavy objects into the spent fuel pool. As long as the integrity of the spent fuel pool and its supportingsystems is maintained,the potentialimpacts of accidentsare bounded by the impacts of those for the spent fuel pool DBAs. After permanentshutdown of the reactor,the only severe accident of concern is one where the fuel in the spent fuel pool becomes uncovered and results in a zircaloy fire. "(Ref. 7.8) The GElS refers to NUREG 1738 Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants which evaluated the probability and consequences of the fuel related accidents. This study concluded that, "The consequences of a zirconium fire event are likely to be severe. "The GElS states that "The consequences for these events are evaluated for the hypothetical maximally exposed individual." (Ref. 7.8) "The impacts of accidents that could result in offsite doses that exceed EPA's protective action guides (PAGs) (EPA 1991) are considered to be destabilizing. The only accidents that are likely to have destabilizing impacts are those that involve pool drainagethat leads to a zirconium fire." (Ref. 7.8) Appendix I of NUREG 0586 provides the details of the accidents evaluated and the consequences.
TSD # 09-020 Revision 00 ( Page 6 of 73 Offsite Whole-Accident Description Nuclear Plant Body Dose, rem Fuel-Related Accidents Cask drop into spent fuel pool Haddam Neck 0.418 Loss of spent fuel pool inventory (loss of heat sink or by inadvertent siphoning) Maine Yankee 0.23 Shipping cask or heavy load drop into fuel element storage well La Crosse 0.186 Loss of prestressed concrete reactor vessel shielding water (after fuel has been Fort St. Vrain 0.035 removed) 100% fuel failure Indian Point, Unit I 0.027 Simultaneous failure of fuel assemblies Dresden, Unit 1 0.016 Spent fuel handling accident Humboldt Bay, Unit 3 0.013 Fuel-handling accident Rancho Seco 0.01 Heavy load drop Fort St. Vrain 0.007 Fuel assembly drop Haddam Neck 0.0026 Radioactive Material -Related Accidents (Non-Fuel) Spent resin handling accident (exothermic reaction during dewatering) 1Haddam Neck 0.96 Explosion inside vapor container Yankee Rowe .0.44 Radioactive liquid waste system leaks and failure Maine Yankee 0.23 Materials-handling event Yankee Rowe 0.16 Fire Fort St. Vramin 0.12 Fire in intermodal container of waste Yankee Rowe 0.1 Fire in D-rings Three Mile Island, Unit 2 0.049 Decontamination events Yankee Rowe 0.039 Liquid radioactive waste released to lake through cracks in building (earthquake- Fermi, Unit 1 0.02364 ( induced) Release of resins from makeup ond purification dernineralizer Three Mile Island, Unit 2 0.02 Figure I Table 1-4 of NUREG-0586 Accidents and Offsite Dose Consequences Based upon this review, "The staff has reviewed activities associatedwith decommissioning and determined that many decommissioning activities not involving spent fuel that are likely to result in radiologicalaccidents are similarto activities conducted during the period of reactor operations. The radiologicalreleases from potentialaccidents associatedwith these activities may be detectable. However, work proceduresare designed to minimize both the likelihood of an accident and the consequences of an accident, should one occur,and emergency plans andprocedureswill remain in place to protect health and safety while the possibility of significantradiologicalaccidents exists." (Ref. 7.8) The radioactive material related accidents (Non-Fuel) pertain to this review of a heavy load dropinto a defueled spent fuel pool. Liquid releases considered in the GElS had off-site dose consequences up to 20 mrem. NEI 96-07 states the following with regard to evaluating the dose consequences of an accident for 50.59 evaluations, The evaluation should determine the dose that would likely result from accidents associatedwith the proposedactivity. If a proposed activity would result in more than a minimal increasein dose from the existing calculated dose for any accident, then the activity would requirepriorNRC approval Where a change in consequences is so small or the uncertaintiesin determining whether a change in consequences has occurred are such that it cannot be reasonablyconcluded that the consequences have actually changed (i.e., there is no cleartrend towards increasing the consequences), the change need not be consideredan increasein consequences." (Ref. 7.11) Therefore dose consequences slightly above those in the GElS are not necessarily considered to be unbounded by the GELS.
TSD # 09-020 Revision 00 Page 7 of 73 NEI 96-07 states, "Therefore, for a given accident, calculated or bounding dose values for that accidentwould be identified in the UFSAR. These dose values should be within the GDC 19 or 10 CFR 100 limits, as applicable, as modified by SRP guidelines (e.g., small fraction of 10 CFR 100), as applicable.An increasein consequences from a proposed activity is defined to be no more than minimal if the increase (1) is less than or equal to 10 percent of the difference between the currentcalculated dose value and the regulatory guideline value (10 CFR 100 or GDC 19, as applicable), and (2) the increaseddose does not exceed the current SRP guideline value for the particulardesign basis event. The current calculateddose values are those documented in the most up-to-date analyses of record. This approach establishes the current SRP guideline values as a basis for minimal increases for all facilities, not just those that were specifically licensed againstthose guidelines."(Ref. 7.11) "Forsome licensees the current calculateddose consequences may already be in excess of the SRP guidelines for some events. In such cases minimal is defined as less than or equal to 0. 1 rem." (Ref. 7.11) A final consideration in the performance of Safety Evaluations for decommissioning facilities is 10 CFR 50.82(a)(6) which states that the licensee must not perform any decommissioning activity that (1) forecloses release of the site for possible unrestricted use, (2) results in any significant environmental impact not previously reviewed, or (3) results in there no longer being reasonable assurance that adequate funds will be available for decommissioning. The NRC staff will, during 50.59 inspections, evaluate the licensee's procedures for ensuring that these three restrictions are part of the screening criteria for changes made to the facility.(Ref. 7.3) 3.2 Previous Evaluations The consequences of a heavy load drop on the Spent Fuel Pool have been previously evaluated for the SAFSTOR Safety Evaluation Report (Ref. 7.17, 7.18) and for the Independent Spent Fuel Storage Installation Safety Evaluation Report.(Ref. 7.19) These evaluations were performed with the fuel pool containing spent fuel elements and were bounded by the FSAR and PSDAR. The Spent Fuel Elements have since been removed from the pool and placed in Dry Cask Storage. The previous evaluations concluded that the only potential consequence from a heavy load drop was contamination of subsurface groundwater and subsequent release of radionuclides to Humboldt Bay and local potable water wells. The potable water wells in use at the time of these evaluations were on-site wells that have since been discontinued. The calculations assumed the heavy load drop would breach the bottom of the pool creating a pathway for release to groundwater. The previous calculations assumed the quantity of the "release was the initial volume of the pool water that would drain until it equilibrated with the water table. They evaluated the release concentrations and source terms for four radionuclides Co-60, Cs-134, Cs-137, and Sr-90 based upon Technical Specification limits for Spent Fuel Pool activity. Fate and transport calculations for the dispersal of these contaminants were performed by calculation rather than by using modeling software in the previous evaluations. In addition, bioaccumulation and dose consequences for the aquatic foods pathway were performed using Regulatory Guide 1.109 (Ref. 7.1) methodology. No credit was taken for tidal flushing of the bay. Sludge samples from the Spent Fuel Pool indicate a wider array of radionuclides present including transuranics. RESRAD software approved by the NRC for modeling fate and transport of radionuclides for License Termination criteria has been updated to allow modeling
TSD # 09-020 Revision 00 Page 8 of 73 of the offsite transport and dose consequences for radionuclides. This software allows modeling of radionuclide release and transport to an off-site surface water body for the wider array of nuclide present in the Spent Fuel Pool. 3.3 RESRAD-OFFSITE The industry has gained considerable experience modeling the fate and transport of radionuclides in the environment while implementing the decommissioning rule. The rule (IOCFR20 Subpart B) requires licensees to determine concentration guidelines that ensure radiation doses of future occupants on the site will not exceed 25 mrem in any one year. The Nuclear Regulatory Commission (NRC), Environmental Protection Agency (EPA), Department of Energy (DOE) and Department of Defense (DOD) have endorsed and used the Residual Radioactivity (RESRAD) codes developed at Argonne National Laboratories for fate, transport and dose modeling for decommissioning and remediation. The RESRAD codes have been tested, validated and benchmarked against other environmental modeling codes. Until recently, these codes evaluated the fate, transport and dose consequences for receptors located onsite, within the contaminated zone. RESRAD-OFFSITE is an extension of the RESRAD (onsite) computer code that was developed to estimate the radiological consequences to a receptor located onsite or outside the area of primary contamination. The code is sponsored by DOE's Office of Health, Safety and Security, and the Office of Environmental Management, with support from the U.S. Nuclear Regulatory Commission. The User's manual is an NRC NUREG.(Ref. 7.21)
" RESRAD-OFFSITE calculates radiological dose and excess lifetime cancer risk with K the predicted radionuclide concentrations in the environment, and derives soil cleanup guidelines corresponding to a specified dose limit.
- Nine exposure pathways are considered in RESRAD-OFFSITE: direct exposure from contamination in soil, inhalation of particulates and radon, ingestion of plant foods, ingestion of meat, ingestion of milk, ingestion of aquatic foods, ingestion of water, and incidental ingestion of soil.
- The conceptual model is presented in Figure 2. The code enables a user to evaluate a scenario where an individual might spend some time in buildings that are located either onsite or offsite. That individual could consume plant- and animal-based foods that are grown onsite or derived from offsite agricultural fields that are contaminated by material from the primary contamination. The water the individual drinks and uses can be drawn from a well or a surface water body located onsite or offsite.
" For a surface water body, it can also be the source where the individual obtained aquatic food for consumption.
K
TSD # 09-020 Revision 00 Page 9 of 73 Boundary of Primary Contamination Onsite
,I ,
- I*
I U!t Figure 2 - Graphic Representation of RESRAD-OFFSITE Conceptual Model This code allows a more complete evaluation of the fate transport and dose consequences for the entire radioactive source term of the spent fuel pool. 4.0 Evaluation and Calculations 4.1 Spent Fuel Pool Structure A model of the Reactor Caisson which includes the Fuel Building is shown in Figure 3. Section 24 of the Unit 3 Plant Data volume (Ref. 7.1) describes the Reactor Caisson, and Fuel Building as follows. "The station building and turbine pedestal are supportedon a 3-6" thick continuous concrete mat foundation resting on a grid of 30 ton timberpiles penetrating to the sand strata at elevation - 24 feet, similarto Units I and 2. The pilings are used to minimize differential settlement relative to the reactorcaisson,the caisson being expected to exhibit very little, if any, settlement... The reactorcaisson consists of a reinforcedconcrete structure 59-6"in diameter, 78-0" inside depth, housing the reactorvessel and auxiliary equipment, the drywell vessel, suppressiontank, spent fuel pit and new fuels storage vault.... "The caisson above elevation -14 foot and up to grade at elevation 12 foot is rectangular(49'-0" wide x 75'-0" long) and serves as the structuralfoundation for the refueling buildingand stack projection."
TSD # 09-020 Revision 00 Page 10 of 73 ( K' Figure 3 - Southwest Subsurface View of Reactor Caisson The refueling building is supportedon the reactorcaisson and six 100 ton H-piles driven to the same strata that supports the caisson. The base of the caisson is sealed with tremie concrete at elevation -66' underneath the dvywell and suppressiontank, and at elevation -14' and -24'in the fuel pit. A 6" pervious gravel blanket on the tremie and below the 6" floor slab collects any seepage and prevents pressure buildup."(Ref. 7.1) Five feet of tremie concrete also underlie Spent Fuel Pit and Cask Pit floors as seen in Drawing 55433. As seen in Figure 5, this drawing shows the tremie concrete, 6 inch thick floors and 6 inches of gravel between the floor and the tremie concrete fuel pit and cask pit. Other notable features described in the plant data volume are as follows, "The refueling building is 43 feet wide x 103 feet long x 35 feet high, constructed of reinforced concrete walls with a composite roof of precastprestressedconcrete double tee sections and concrete topping. The 12 inch minimum thickness walls and roof provide containment and shielding of any fuel handling accident.A negative pressureof 1/4 inch water is maintainedon the refueling building so that any leakage is inward ratherthan to the environs."(Ref. 7.1) The Unit 3, Final Hazards Summary Report (Ref. 7.17) states, The Fuel Building is "Designed for a permissibleleakage rate not to exceed 100% of its volume perday at 1/4 inch water pressuredifferential. The structuralelements of the Refueling Building have been designed to resist loadings due to earthquake,wind and live load."
TSD # 09-020 Revision 00 Page 11 of 73 Figure 4 - Top View of Fuel Pit and Cask Pit from Drawing 55466 The Fuel Pit is constructed as part of the Reactor Caisson. As seen in Figure 4, the Fuel Pit is 20 feet wide by 26 feet long. The Cask Pit is 10 feet wide by 12.5 feet long. Figure 4 also shows the Fuel Building Floor to be at grade which is elevation + 12 feet. As seen in Figure 5, the fuel pit is from Elevation 12 feet to Elevation -14 feet, thus the Fuel Pit is 26 feet deep from the floor level. The Cask Pit floor is at -24 foot elevation, or 10 feet deep below the Fuel Pit floor. The drawings also show design features from the construction of this portion of the caisson. The sheet piling installed to enclose the Fuel Pit excavation area is shown in Figure 5. The sheet piling was installed and soil was excavated from within it. Five feet of tremie concrete was then poured under the water in the excavation to seal the bottom of the excavated pit against the sheet piling. The accumulated water was pumped out and 6 inches of gravel were placed on the tremie concrete base, the gravel was covered with tar paper, and 6 inch thick concrete floors were poured over it as shown in Figure 5 and Figure 6. This gravel void space can be pumped and sampled. As described in the Unit 3 Decommissioning, Safety Evaluation Report (Ref. 7.18), early in the operation of Unit 3, Spent Fuel Pool leakage was detected, and a stainless steel liner was installed to alleviate the problem. Approximately 50 liters (12 gallons) of water has historically been pumped from the liner void space every 5,to 7 days with leakage from the pool accounting for about 5 percent of this volume. Sampling of the gravel (French drain) under the Fuel Pit/Cask Pit floor, is conducted on a periodic basis. Cs-I 37 and Cs-134 radionuclide concentrations in the blotter samples are approximately 1 percent of the concentrations found
TSD # 09-020 Revision 00 Page 12 of 73 in the liner void space. The radionuclide concentrations are below the liqu id effluent limits specified in 10 CFR 20.
#4/0C I II [J54~(2~o4j Ii U h"~'. ~e 4ee-, .~9'-Q" Figure 5 - Structure and Elevation of Fuel Pit and Cask Pit from Drawing 55433
TSD # 09-020 Revision 00 Page 13 of 73 Figure 6 - Fuel Pit and Cask Pit
TSD # 09-020 Revision 00 Page 14 of 73 4.2 Spent Fuel Pool Volume and Source Term The Spent Fuel Pool was walked down on Wednesday, April 29e, 2009. The level of the Spent Fuel was observed to have a water level that was 2 feet below the 12' floor elevation (e.g., 10' Elev.). Using this water level', the water volume in the pool is calculated as shown in Table 1. Table 1 - Calculated Water Volumes of Fuel Pit and Cask Pit Cubic Length Width Height Feet Gallons Liters Fuel Pool 26 20 24 12,480 93,363 3.53E+05 Cask Pit 12.5 10 1 10 1 1,250 9,351 3.54E+04 Total 13,730 102,714 3.89E+05 2 There is a potential for a layer of high specific activity sludge to be accumulated on the floors of the Fuel Pit and Cask Pit. In order to ensure that all the fuel was recovered prior to sealing the final fuel dry cask storage assembly, the pool was vacuumed removing the bulk of the sludge. The laboratory analysis results for a Spent Fuel Pool Sludge sample obtained in February 2000 and decayed to 05/01/2009 are shown in Table 2. Table 2 - Spent Fuel Pool Sludge Laboratory Source Term Part 61 Decay 2/17/2000 Half Life Constant Decayed 'K Nuclide pCi/gm (Years) y.j pCI/gm H-3 8.88E-04 1.23E+01 5.64E-02 5.29E-04 C-14 1.14E-02 5.73E+03 1.21E-04 1.13E-02 Fe-55 1.84E+01 2.70E+00 2.57E-01 1.73E+00 Co-60 2.77E+01 5.27E+00 1.31E-01 8.26E+00 Ni-59 1.11E-01 7.50E+04 9.24E-06 1.11E-01 Ni-63 1.82E+01 1.00E+02 6.92E-03 1.71E+01 Sr-90 5.37E-01 2.86E+01 2.42E-02 4.30E-01 Tc-99 1.38E-04 2.13E+05 3.25E-06 1.38E-04 1-129 < 1.19E-04 1.57E+07 4.41 E-08 1.19E-04 Cs-134 < 5.27E-02 2.06E+00 3.36E-01 2.39E-03 Cs-137 2.38E+00 3.02E+01 2.30E-02 1.93E+00 U233/234 2.41 E-04 1.58E+05 4.39E-06 2.41 E-04 U235/236 6.62E-05 2.34E+07 2.96E-08 6.62E-05 U-238 9.62E-05 4.47E+09 1.55E-10 9.62E-05 Eu-154 1.02E-01 8.80E+00 7.88E-02 4.96E-02 Pu-238 1.27E-01 8.78E+01 7.90E-03 1.18E-01 Pu-239/240 1.36E-01 2.41 E+04 2.87E-05 1.36E-01 Pu-241 3.31 E+00 1.44E+01 4.81 E-02 2.13E+00 Am-241 1.17E+00 4.32E+02 1.60E-03 1.19E+00 The height at which the water level is maintained in the pool is not critical since 86% of the source term is in the sludge at the bottom of the pool. 2 The dimensions of the contaminated zone in the RESRAD-OFFSITE model were chosen to replicate this volume.
TSD # 09-020 Revision 00 Page 15 of 73 Part 61 Decay 2/17/2000 Half Life Constant Decayed Nuclide pCi/gm (Years) y1 pCi/gm Cm-2431244 1.94E-01 2.85E+01 2.43E-02 1.55E-01 Key Nuclide Ratios Cs-1 37/Sr-90 4.43E+00 4.49E+00 Cs-137/Co-60 8.60E-02 2.33E-01 Co-60/Am-241 2.38E+01 6.96E+00 Cs-137/Am-241 2.04E+00 1.62E+00 Gross Beta/Gross Alpha 2.09E+01 7.98E+00 Table 3 - Spent Fuel Pool Sludge Laboratory Analysis Result The decayed activity was calculated using the standard radioactive decay equation for all radionuclides except Am-241. Am-241 is the daughter of Pu-241 which has a shorter half-life resulting in in-growth of Am-241 as Pu-241 decays. The equation used to calculate the decayed Am-241 activity is shown in Equation 1. AAm-241 =AOAm eA' + AM A ( -e:' )(e 2"') Where: AAm-241 = The decay corrected Am-241 activity AoM = The original Am-241 activity Aop, = The original Pu-241 activity Am = The Am-241 decay constant yr' A= The Pu-241 decay constant t yr"1 t = the decay time in years The surface area of the bottom of the Fuel Pit and Cask Pit is 26 feet by 20 feet. Assuming a sludge depth of 1/8 inches yields 153,383 cm3 of sludge on the floor. Assuming a density of 1.6 grams/ cm 3 , this volume equals 245,413 grams of sludge. Using the decay corrected specific activities in Table 3, the estimated sludge source term is calculated as shown in Table
- 4. A small bucket of sludge is also stored in the bottom of the pool. It contains 907 cubic inches (e.g., 14,863 cm3) of sludge. This is less than 10% of the conservative volume estimated in this calculation and is therefore bounded by the assumed 1/8 inch thick sludge layer.
The decay corrected sludge source term, scaling factors and scaling nuclides are provided in Table 4. Table 4 - Estimated Spent Fuel Pool Sludge Source Term and Scaling Factors Scaling Scaling Nuclide pCil/gram IPCi Ci pCilg % Mix Factor Nuclide Am-241 1.19E+00 2.92E+05 2.92E-01 1.19E+06 3.56% 1.79E+04 Am-241 C-14 1.13E-02 2.78E+03 2.78E-03 1.13E+04 0.03% 1,37E-03 Co-60 Cm-243/244 1.55E-01 3.80E+04 3.80E-02 1.55E+05 0.46% 2.34E+03 Am-241 Co-60 8.26E+00 2.03E+06 2.03E+00 8.26E+06 24.78% 1.OOE+00 Co-60
TSD # 09-020 Revision 00 Page 16 of 73 Scaling Scaling Nuclide pCi/gram jCi Ci pCi/g % Mix Factor Nuclide Cs-134 2.39E-03 5.87E+02 5.87E-04 2.39E+03 0.01% 2,16E-02 Cs-137 Cs-I 37 1.93E+00 4.73E+05 4.73E-01 1.93E+06 5.78% 1.74E+01 Cs-I 37 Eu-154 4.96E-02 1.22E+04 1.22E-02 4.96E+04 0.15% 6.OOE-03 Cs-137 Fe-55 1.73E+00 4.24E+05 4.24E-01 1.73E+06 5.18% 2.09E-01 Co-60 H-3 5.29E-04 1.30E+02 1.30E-04 5.29E+02 0.00% 1-129 1.19E-04 2.92E+01 2.92E-05 1.19E+02 0.00% 1.07E-03 Cs-137 Ni-59 1.11E-01 2.72E+04 2.72E-02 1.11E+05 0.33% 1.34E-02 Co-60 Ni-63 1.71E+01 4.20E+06 4.20E+00 1.71E+07 51.28% 2.07E+00 Co-60 Pu-238 1.18E-01 2.91 E+04 2.91 E-02 1.18E+05 0.35% 1.79E+03 Am-241 Pu-239/240 1.36E-01 3.33E+04 3.33E-02 1.36E+05 0.41% 2.05E+03 Am-241 Pu-241 2.13E+00 5.22E+05 5.22E-01 2.13E+06 6.37% 3.21 E+04 Am-241 Sr-90 4.30E-01 1.06E+05 1.06E-01 4.30E+05 1.29% 3.88E+00 Cs-137 Tc-99 1.38E-04 3.38E+01 3.38E-05 1.38E+02 0.00% 1.24E-03 Cs-137 U233/234 2.41E-04 5.91E+01 5.91E-05 2.41E+02 0.00% 3.64E+00 Am-241 U235/236 6.62E-05 1.62E+01 1.62E-05 6.62E+01 0.00% 1.OOE+00 Am-241 U-238 9.62E-05 2.36E+01 2.36E-05 9.62E+01 0.00% 1.45E+00 Am-241 Total 8.19E+06 8.19E+00 O1.0E+00 The current (March -2009) concentrations of radionuclides in the Spent Fuel Pool are provided in Table 5. These are the results of routine sampling performed on the Spent Fuel Pool by Radiation Protection. i, Table 5 - Spent Fuel Pool Water Concentrations Nuclido RCIIml Cs-137 6.04E-07 Co-60 5.21E-07 Am-241 8.69E-08 Np-239 1.90E-08 H-3 3.OOE-05 The Table 5 water concentrations and Table 4 scaling factors were used to provide an estimated current water inventory. The scaled water inventory is provided in Table 6. Table 6 - Scaled Spent Fuel Pool Water Source Term Sludge Scaling Scaling Nuclide Nuclide Factor iclImI- Cl H-3 NIA NIA 3.00E-05 1.17E-02 C-14 Co-60 1.37E-03 7.16E-10 2.78E-07 Fe-55 Co-60 2.09E-01 1.09E-07 4.24E-05 Co-60 Co-60 1.00E+00 5.21E-07 2.03E-04 NI-59 Co-60 1.34E-02 6.99E-09 2.72E-06 Ni-63 Co-60 2.07E+00 1.08E-06 4.19E-04 Sr-90 Cs-137 3.88E+00 2,34E-06 9.11E-04 Tc-99 Cs-137 1.24E-03 7.50E-10 2.92E-07 1-129 Cs-137 1.07E-03 .6.47E-10 2.52E-07 Cs-134 Cs-137 2.16E-02 1.30E-08 5.06E-06 Cs-137 Cs-137 1.74E+01 6.04E-07 2.35E-04 U233/234 Am-241 3.64E+00 3.16E-07 1.23E-04
TSD # 09-020 Revision 00 Page 17 of 73 Sludge Scaling Scaling Nuclide Nuclide Factor uCilml ci U235/236 Am-241 1.00E+00 8.69E-08 3.38E-05 U-238 Am-241 1.45E+00 1.26E-07 4.91E-05 Eu-154 Cs-137 6.OOE-03 3.62E-09 1.41E-06 Pu-238 Am-241 1.79E+03 1.55E-04 6.04E-02 Pu-239/240 Am-241 2.05E+03 1.78E-04 6.93E-02 Pu-241 Am-241 3.21E+04 2.79E-03 1.08E+00 Am-241 Am-241 1.79E+04 8.69E-08 3.38E-05 Cm-243/244 Am-241 2.34E+03 2.03E-04 7.90E-02 Np-239 N/A NIA 1.90E-08 7.37E-06 Total 3.33E-03 1.30E+00 The combined sludge and water source terms are provided in Table 7. The total volume of the water in the spent fuel pool in Table I is used to estimate the overall concentration of the water in the Spent Fuel Pool in the last column of Table 7. The sludge comprises 86% of the overall source term in the Spent Fuel Pool. Table 7 - Combined SFP Sludge and Water Source Terms and Overall Concentration Overall 3 Nuclide Water Ci Sludge Ci Total Cl pCi/ml H-3 1.166E-02 1.297E-04 1.179E-02 3.033E-05 C-14 2.783E-07 2.785E-03 2.785E-03 7.163E-06 Fe-55 4.241E-05 4.244E-01 4.245E-01 1.092E-03 Co-60 2.027E-04 2.028E+00 2.028E+00 5.217E-03 Ni-59 2.717E-06 2.719E-02 2.719E-02 6.994E-05 Ni-63 4.195E-04 4.198E+00 4.198E+00 1.080E-02 Sr-90 9.107E-04 1.055E-01 1.064E-01 2.738E-04 Tc-99 2.916E-07 3.379E-05 3.408E-05 8.767E-08 1-129 2.516E-07 2.916E-05 2.941E-05 7.564E-08 Cs-134 5.064E-06 5.869E-04 5.919E-04 1.522E-06 Cs-1 37 2.346E-04 4.734E-01 4.736E-01 1.218E-03 U233/234 1.229E-04 5.909E-05 1.820E-04 4.680E-07 U235/236 3.378E-05 1.624E-05 5.002E-05 1.287E-07 U-238 4.909E-05 2.361E-05 7.270E-05 1.870E-07 Eu-154 1.409E-06 1.218E-02 1.218E-02 3.132E-05 Pu-238 6.041E-02 2.905E-02 8.946E-02 2.301 E-04 Pu-239/240 6.928E-02 3.332E-02 1.026E-01 2.639E-04 Pu-241 1.085E+00 5.217E-01 1.606E+00 4.132E-03 Am-241 3.378E-05 2.915E-01 2.915E-01 7.498E-04 Cm-243/244 7.899E-02 3.799E-02 1.170E-01 3.009E-04 Np-239 7.368E-06 7.368E-06 1.895E-08 Total 1.307E+00 8.186E+00 9.493E+00 2.442E-02 3 The Overall Activities concentrations were converted to pCilgram and used as the Contaminated Zone concentrations in the RESRAD-OFFSITE model.
TSD # 09-020 Revision 00 Page 18 of 73 4.3 Heavy Load Drop Scenario On-Site Consequences The likely consequences of a heavy load drop in the Spent Fuel Pool are that the sludge would become suspended in the water due to the turbulence created by the drop, some of the water would be splashed to the floor. The liner, cask pit floor or fuel pit floor, and tremie concrete would be damaged creating a pathway for draining and release of spent fuel pool water to the environment.below the caisson. This would cause the water in the Spent Fuel Pool to drain until it equilibrated with groundwater levels in the water table. As will be seen in later section, this will leave sufficient water in the pool to shield direct radiation from any items stored in the lower sections of the Fuel Pit or Cask Pit. Thus direct radiation levels would not hinder the response to the event or pose an on-site threat that is outside those encountered during the course of decommissioning. Due to the design of the Fuel Building and decommissioning on-site response capabilities the on-site consequences would be minimal. Work such as a heavy load movement in and around the Spent Fuel Pool would require Health Physics coverage. Spill kits and decontamination supplies would enable splashed water to be contained and collected. The contaminated structures and floors would be decontaminated and the building design and ventilation would contain any resulting'airborne radioactivity as the splash area and fuel pool wall dried. Similarly, the exposed walls of the fuel pit could be washed down and periodically wetted to minimize airborne radioactivity. Upon release to-the subsurface environment below the caisson, subsequent release and fate and transport of the radionuclides is controlled by the hydrogeological features of the site and ( the marine environment of Humboldt Bay. 4.4 Stratigraphy and Aquifers Underlying Unit 3 Recently, the groundwater in the ISFSI Site Area was investigated over a several year period by Pacific Gas and Electric (PG&E). The geology and hydrology determined from this investigation are described in Independent Spent Fuel Storage Installation (ISFSI), Final Safety Analysis Report Update (ISFSI FSAR).(Ref. 7.19) The (FSAR) states, "Two areas were investigatedin detail, one nearthe Unit 3 Power Plantand one nearthe former wastewater pond site that is east of Unit 3. The various borings used to establish the stratigraphy, including those that held piezometers and monitoring wells, are shown in Figure2.5-3" (provided in Attachment 1). "Table 2.5-1 of the FSAR summarizes the basic information about the 67 borings and monitoring wells used to measure the piezometric levels taken on May 6, 1999 ...... Based on the information from these borings and analysis of the stratigraphyand aquifer characteristics,several aquifers and zones of perched groundwaterin the ISFSI site area are evident. The currentinterpretationof the groundwateraquifers and zones varies significantly from earlierinterpretationsbecause the strata within the Hookton Formationare better understood.Also, in the earlierinterpretationsthe Holocene bay deposits were lumped with the Hookton, but are now separatedand shown to unconformably overlie the upper Hookton Formation.In addition, the tectonic tilting and faulting of the Hookton Formation in part controls water movement and piezometric levels." Thus a review of the detailed results of the studies is warranted to ensure calculations and modeling are based upon the current understanding of hydrological conditions. Drawing 55428 provides detailed information about the geologic strata surrounding the Unit 3 Reactor Caisson. The stratigraphy information has been excerpted from the drawing is provided in Figure 7. The elevations and dimensions shown on the drawing were interpolated
TSD # 09-020 Revision 00 Page 19 of 73 from the image and drawing details. The Humboldt Bay facility is located on Buhne Point which on Humboldt Bay. Figure 2.5-5 of the ISFSI FSAR (Ref. 7.19) shows the geologic cross section of Buhne Point based upon the above review of the hydrogeologic data. This figure is provided as Attachment B in this document. Figure 8 was prepared from Attachment to show the details of the geologic stratigraphy and aquifers underlying Unit 3. The elevations of the bottoms of the Fuel Pit and Cask Pit have been marked on the figure to illustrate the subsurface depths and features into which the contents of the Spent Fuel Pool would be released upon breach.
TSD # 09-020 Revision 00 Page 20 of 73 ( 1 11 F-L-(-) X-C)" Table Water Water Table TIde High*1 +7'6" 1] h1b.Md
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W6 C MeanTide 6'0" SaId '.g, ss-
/Low Tide 4 -, -SP Poorly graded sand a or gravelly sands, 0 o w. 4', 5"- m little or no fines.
0SC"4 * , A/ ) SM = Silty sands, sandlsli t mixtures
.0- 2" CL = Inorganic clays of lo w to medium a j" plasticity, garvelly clays, sandy clays, ioamn
' -clays 0
'~ez
,~0~.(~, ~ OL - Organic slits and or ganic silt clays of low plasticity 7'
or. 0 0 0 OtD
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11 .if (Iaj S(L~hof( G,'*v1) Fruwn7Ddte rmoa Coar.,a -Sand ~~ Figure 7 - Detailed Strata for Reactor Caisson from Drawing 55428
TSD # 09-020 Revision 00 Page 21 of 73 croes Swimb A-A West East X
~-un'tL 03.
1M -
?7,nD of po-.!'od qwordsvtor In Fuel Pit Flo6-_-l*f(A3- it) tihoUppezr V'cokt~n WIIt and clay bods Cask Pit Floor SIlY, SAND, SAND AND SILl
- 24kt (-7.3 nxtS -m?
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.qj M-0 WN A),.TH GRAVEL. TN.AeftlldlI F ch~y amd
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- l I I I I I I I I 39 ,490 4110 4Z0 430 440 450 400 470
-- -.- -. -- Lithologic contoct. dashed where approximate, queried where Inferred Note:
Location of cross section Is shown on Figure 2,6-3, Figure modiflid from Figuro 2.6.4-5. Figure 8 - Unit 3 Geologic Cross Section from FSAR Figure 2.5-5 (Attachment B) Figure 7 and Figure 8 clearly show that the bottoms of the Fuel Pit and Cask Pit are within the Upper Hookton brackish water aquifer deposits. Thus the postulated breach would result in release of radioactive source term to these deposits. Figure 7 shows that the Upper Hookton brackish water aquifer is overlain by semi-permeable alluvial sand and clay deposits that are approximately 19' 4" or 5.884 meters thick. Due to the clay and semi-permeable nature of the overlying layer, transport will occur mainly via the Upper Hookton Aquifer deposits that underlie this cover material. The ISFSI FSAR (Ref. 7.19) describes the Upper Hookton deposit as follows, "The upper Hookton Formation in the ISFSI site area can be divided into two informal lithologic units 4 This value is used as the thickness of the Contaminated Zone in the RESRAD-OFFSITE Physical and Hydrological - Contaminated Zone and Cover input form.
TSD # 09-020 Revision 00 Page 22 of 73 'upperHookton silt and clay beds' and the 'upperHookton sand beds. The upperunit is 60 to 80 ft thick and consists of laterallydiscontinuousbeds of clay and silt, and sand and gravel that change laterallywith interfingering,cut-and-fill, and gradationalfacies changes. The clay beds that are ancient bay sediments have more lateralpersistence than interbeddedsandy and silty layers..... The upper Hookton sand beds are 25 to 40 ft thick and consist of sand and gravel layers with lesser silt and clay beds. The upperHookton sand beds overlie a discontinuousclay bed (the 'secondbay clay) that underlies the Unit 3 power plant area and the waste disposalponds where it is 8 to 13 ft thick and is present in much of the site area." The FSAR describes the aquifer as follows," 'UpperHookton aquifer'- The upperHookton aquifer is the brackish water aquiferin the Upper Hookton sand beds above the 2nd bay clay and below the overlying silt and clay beds of the Upper Hookton Formation. ", Perched groundwater sits atop the It Bay Clay which overlies the Upper Hookton sand deposits into which the release will occur. "Basedon the definite piezometric head separation between the zone of perchedgroundwaterand the upper Hookton aquiferand the 1st bay clay that separatesthem, hydraulic communication between the two aquifers is poor; hence, minimal flow are believed to occur between these two zones. The perched groundwaterin the Upper Hookton Formation appearsto dischargeinto the nearby marshes and into the intake and dischargecanals. Little dischargeis expected to reach the underlying Upper Hookton aquiferbecause the 1st bay clay that is at the base of the deposit restricts vertical flows. Moreover, in the Unit 3 area the piezometric surface of the underlying upper Hookton aquifer is higher than the base of the 1st bay clay providing upwardpiezometric pressure into the perched groundwaterzone."6 (Ref. 7.19) Thus modeling of site surface contamination should emulate the Saturated Zone of the perched groundwater and discharge into nearby marshes and canals. Modeling of subsurface releases below the first clay layer should emulate the conditions in the Upper Hookton aquifer sand deposits that overly the second clay layer. 6 The Lower Hookton deposit includes a clay bed that acts as an aquitard and inhibits migration from the Upper Hookton brackish water aquifer. The ISFSI FSAR (Ref. 7.19) describes the Lower Hookton deposits as follows, "Lower Hookton Formation- The lower Hookton Formation consists of laterallypersistent beds of alternatingsand,silty sand,gravel, gravely sand, silty clay, and clay. The upper 26 ft to 150 ft consists of sand and gravel that overlies the Unit F clay. The Unit F clay, which is about 50 ft thick, is a distinctive marker bed (Section 2.6.4) with relatively low permeability that functions as a regionalaquitard.Beneath the Unit F clay are alternatinglayers of clean, well-sorted sand and clay that extend from 200 to about 1,100 ft deep." The lower Hookton aquiferlies below the 50 ft thick, regionalaquitardknown as the Unit F clay. Beneath this impermeable layer, the aquifer is defined as the freshwaterbearing zone of clean, sorted sands that are deeper than about 200 ft below the ISFSI. Although the sand layers extend deeper, they are utilized in wells above 450 ft depth, which defines the boundary of interest for the groundwaterflow directionsand gradientsat the ISFSI. This confined aquiferis artesianin places." From the above description, the course sand and gravel beds of the Upper Hookton brackish water aquifer are isolated from the fresh water of the Lower Hookton aquifer by 50 foot thick Unit F clay bed. This aquitard prevents cross contamination by the Upper Hookton brackish waters and will also prevent migration of radionuclides into the fresh water aquifer of the lower (
TSD # 09-020 Revision 00 Page 23 of 73 Hookton. 5 Figure 9 provides further stratigraphic information relevant to evaluating the fate and transport of the released radionuclides. HOOKTON AQUIFERS IN HOOKTON FORMATION FORMATION Stratigraphy This Report Earlier Interpretations A Silty sand and Zone of perched silt beds with groundwater in Unconfined first sand lenses Upper Hookton water bearing zone of Silt and clay clay and silt Bower (1988) [in TES' beds beds 1988) 1 st bay clay B 1st Sands and Upper Hookton C aquifer gravels aquifer Semi-unconfined of Bower second water bearing .(1988) zone of Bower (1988) (brackish [in TES, 1988] Upper water) [in sand zone of Dames TES, and Moore (reported 1988] D in WCC) Clay bed Aquitard Clay layer of Bower 2 nd bay clay discontinuous (1988) [in TES,1988] across site Sands and Aquifer between gravels Unit F clay and 2Idbay clay Unit F clay Unit F clay Regional aquitard I aquitard Sands and Lower Hookton 2na aquifer of Bower gravels aquifer 1998 (fresh water) I_ [in TES, 1988] Figure 9 - Description of Hookton Geologic Formations and Aquifers from Figure 2.5-4 of FSAR. The ISFSI FSAR (Ref. 7.19) provides the following details about the Upper Hookton aquifer.
"UpperHookton Aquifer- Above the Unit F clay aquitardand below the upper Hookton silt and clay beds (comprisingpermeable beds in both the lower and upper Hookton Formation) is the shallow, brackish-wateraquifer which is over 100 ft thick. It is semiconfined by the uppersilt and clay bed aquitard 6 . The unit is comprised of sand and gravel lenses, including some clean sand strata.A clay bed of varying thickness and extent is about 20 ft below the top of the aquifer. This clay bed is shown as the second bay clay in the geologic sections and has been referred to as a site-wide aquitard(clay layerof Bower, 1988; in TES, 1998, Reference 6). An 5 The RESRAD-OFFSITE model assumes there is no viable contamination of a potable water source and no ingestion dose from drinking water.
6 Because RESRAD-OFFSITE models release to the groundwater from a Contaminated Zone that is in the Unsaturated Zone above the water table, and the deposits into which the radioactivity release occurs are semi-confined by the overlying deposits, the RESRAD Model places the Saturated Zone water table at the bottom of the 19'4" thick upper silt and clay bed.
TSD # 09-020 Revision 00 Page 24 of 73 analysis,however, shows that it is discontinuous;in Figure 2.5-8, the clay bed bifurcates: the upperpartpinches out and the lower part appearsto pinched out to the west of the western most boring; in Figure 2.5-7 the upperbifurcation of the clay bedpinches out. The lower part of the bifurcation is below the borings; however, it is not present in the deeperborings (D&M 59-1A and D&M73-3) on the up-dip projection of the clay bed. The 2nd bay clay is present beneath the ISFSI site as illustratedin Figures 2.5-5 and 2.5-6." (Ref. 7.19)7 The pinching out or bifurcation is a feature underlying the ISFSI on the Buhne Point Hill east of Unit 3. "As evident on the cross sections, the upper Hookton aquifer is confined by the upper Hookton silt and clay beds in the Unit 3 and wastewaterponds area,but is unconfined beneath the higher part of Buhne Point Hill, making it a semi-confined aquifer."(Ref. 7.19) In summary, the hydrogeology that underlies Unit 3 indicates that upon breach, the fuel pool water will be injected into the sand deposits of the Upper Hookton aquifer. The aquifer is confined between an upper clay layer and a lower clay layer. The upper clay layer limits transmissivity to the perched groundwater above it. The upper deposits are approximately 19' 4" thick. A second clay layer below the sands in which the release would occur will confine flow and reflect dispersion as is modeled by RESRAD-OFFSITE.(Ref. 7.21) The Unit F clay aquitard separates the Upper Hookton Brackish water aquifer from the lower Hookton fresh water aquifer and will prevent migration of radionuclides into the freshwater aquifer. Thus there is no viable potential for contamination of a potable water supply from the postulated breach and release. 4.5 Water Table Depths and Aquifer Gradients ( The ISFSI FSAR (Ref. 7.19) provides the following details about the water table of the perched groundwater overlying the first clay bed for the fuel pool area and the groundwater gradients of Buhne Point. "The characterof the Upper Hookton aquifer is known from severalpiezometers and monitoring wells in the wastewaterpond areaand in the Unit 3 area (Table 2.5-1 provided as Figure 10). The monitoring wells were input formed at two intervals: the C-level monitoring wells were input formed in the upperportion of the aquifer and the D-level monitoring wells were input formed at a deeperlevel in the aquiferbut above the second bay clay "aquitard." Several other wells also record the piezometric surface of the upper Hookton aquifer on Buhne Point Hill." (Ref. 7.19)
"The piezometric surface in May 1999 from the Upper Hookton aquiferis shown in the cross sections (Figures2.5-5 to 2.5-8) and as contours in Figure 2.5-9."(Ref. 7.19) The portion of this map near Unit 3 is provided as Attachment C. The map shows the Upper Hookton groundwater contours and the well locations. "Analysis of the figures shows that the piezometric levels for both the C and D zones are essentially identical,indicatinggood vertical communication in the aquiferabove the second bay clay bed. The piezometric surface beneath Buhne Point Hill is nearly horizontal, and slopes gradually to the north toward Humboldt Bay. North of the Discharge Canal fault piezometric surface slopes northwest.
The difference in the amount and direction of slope of the piezometric surface on eitherside of the fault indicates that the fault is an aquitard,with higher water levels on the north side than the south." (Ref. 7.19) The MLLW pieziometric surfaces near Unit 3 and approaching the bay are shown in Attachment C. The RESRAD-OFFSITE model assumes the Saturated Zone is an unconfined aquifer with a reflective mirror or aquitard that is twice the depth of the modeled water table (e.g., 19' 4"). The calculations reasonably approximate the Upper Hookton aquifer characteristics.
TSD # 09-020 Revision 00 Page 25 of 73 PIEZOMETERS USED IN 1999 GROUNDWATER MEASUREMENTS IN THE HUMBOLDT BAY ISFSi SITE AREA Piezomnetric Boring Top Bottom Elevation Depth/ Screen Screen Geologic/ 516/99 Boring Elevation Elevation Elevation Hydrologic Unit (9am-12pm) Number Year (feet) (feet) (feet) in screened zone (feet) MW-1 1984 49.51 -28.19 -32.59 upper Hookton aquifer 4.74 (BEC 84-1) -37.6 MW-2A 1984 50.0/ -28.14 -37.54 upper Hookton aquifer 4.29 (BEC 84-2A) -39.2 MW-4 1984 50.61 -41.00 -50.20 upper Hookton aquifer 4.43 (BEC 84-4) -38.5 MW-5 1984 45-01 -40.50 -44.80 upper Hookton aquifer 4.24 (BEC 84-5) -33.3 MW-6 1984 50.0/ -32.57 -36.87 upper Hookton aquifer 4.21 (BEC 84-6) -38.6 MW-7 1984 45.0/ -16.23 -20.53 upper Hookton aquifer 4.10 (BEC 84-7) -20.9 MW-8 1984 12.51 17.3 11.8 perched ground-viater 17.92 (BEC 84-8) 11.1 zone (A) in upper Hookton silts and I___ _ Iclays MW-9 1984 45.0/ 58 -32.78 upper Hookton aquifer 4.76 (BEC 84-9) -33.4 1 1 Figure 10- Monitoring Well Designations In Unit 3 Area from Table 2.5-1 of FSAR As seen in Figure 11, the tides have a strong influence on the perched groundwater overlying the first clay bed of the Upper Hookton piezometric surfaces. This is illustrated in wells at the wastewater pond site and near Unit 3. The piezometric elevations for these wells are provided in the last column of Figure 10. Figure 10 also provides a cross index to the well designations used in Attachment C. "The piezometric surface lags the tidal changes by a few hours and has up to about a 3 ft elevation change during a tidal cycle. This indicates that water in Humboldt Bay and in this aquifer at the ISFS/ site areais connected in the outcrops below the bay."(Ref. 7.19)
TSD # 09-020 Revision 00 Page 26 of 73 (. BECHTEL W.,IS (1, 2, 6. 7, 9 & TIDE) - .tHASE I
.41 66 U2 0
['-IE N ) .. . ... . ... .. ...*.... ..- - - Fl'ilMl! (i)AY 3 19, 0000 H-RS - DAY 322, 0230 ]IRS,"i ..f) Figure 11 - FSAR Figure 2.5-10 Relationship Between The Tide Levels In Humboldt Bay and Piezometric Levels from Wells MW-1, MW-2, MW-6, MW-7, and MW-9 (Bechtel) Near.Unit 3 Humboldt Bay 1SFSI Site Area. Thus the zone of perched ground water is tidally influenced. It is also influenced by the seasonal rainfall and surface water runoff and recharge characteristics. The ISFSI FSAR (Ref. 7.19) describes the perched groundwater as follows, "Rechargeinto the zone of perched groundwaterin the upper Hookton silt and clay beds beneath Buhne PointHill at the ISFSI site is primarilyfrom direct precipitationand percolationinto the interfingeringlayers of silt, clay and lesser sand lenses that characterizethe deposits. Local perched water tables occur in these beds, but the southeasttilting of these layers tends to direct groundwaterflow toward the intake and discharge canals. Near Unit 3, the perched water table is at about 8. 5 ft elevation. This wateris somewhat brackish (salinity about 2600 to 2800 micromhos/cm) reflecting a mixing with some bay waterfrom the nearby marshes and the intake and dischargecanals, or from upwardmigrationof water into these beds from the underlying upper Hookton aquifer. The rechargepotentialon. Buhne PointHill is low because the silty sand, silt and clay deposits directly below groundare relatively impermeable."(Ref. 7.19) Tidal fluctuations also affect the Upper Hookton aquifer in the sand deposits below the jst clay layer. "Tidal fluctuations in Humboldt Bay have significant short-term (hours)effects on the groundwaterflow directions and rates within the UpperHookton aquifer at Buhne PointHill. Duringrising tides, bay water flows into the formation near Buhne Point Hill in a generally southerly direction; duringfalling tides, the flow is out of the formation into the bay, generally in
TSD # 09-020 Revision 00 Page 27 of 73 a northerly direction. However, the upper Hookton aquiferis believed to have a net discharge of groundwaterinto Humboldt Bay and possibly offshore into the Pacific Ocean. Net horizontal flow velocities within the Upper Hookton aquifer range from 2 x 10-7 to I x 105 cm/s." (Ref. 7.19) This statement makes it clear that the Upper Hookton aquifer in the sand deposits discharges to the bay or to the Pacific and not to the local marshes as described for the perched groundwater. The flow velocities of 2 x 10.7 to 1 x 10-5 cm/s corresponds to a horizontal hydraulic conductivities of 0.0631 m/year to 3.15 m/year. As seen in Table 8, previous calculations used a Lateral Dispersion value of 1.524E-01 meters. The ISFSI FSAR later states, "Basedon down-hole flow meter measurements in the Upper Hookton aquiferin the Unit 3 area for wells MW- I through MW- Il and calculatedpermeability using the tidal method, a flow velocity range of 3,100 to 10,400 ft'yr (3x10o to 3xi0 2 cm/sec) was calculated. This range is higherthan that calculated for the aquifer beneath the wastewaterponds area (describedabove) and on the high side of those values calculatedfor References 6 and 10 (2,000 ft/yr or 1.9 x 10-3 cm/s). The differences most likely reflect different local stratigraphiccharacteristicsin the aquifer." (Ref. 7.19) Previous calculations (Ref. 7.17, 7.18) used the 10,400 ftlyr value as the hydraulic conductivity forthe Fuel Pool Breach release. This corresponds to a hydraulic conductivity of 3,170 meters/year. 8 The ISFSI FSAR (Ref. 7.19) states, "A tidal fluctuation analysis method was appliedto water level data collected from wells completed in the UpperHookton aquiferto provide estimates of the transmissivity,hydraulic conductivity, and storativity of that zone. The tidal method was not appropriatefor the perchedgroundwaterzone because tidally induced fluctuations in this zone were negligible."(Ref. 7.19) "Little vertical flow occurs within the upperHookton aquifer. Vertical gradientsrange from 10 to 20 ft/mile (0.002 to 0.004 ft/ft) 9 . During the 1988 study period, horizontalgroundwatergradientswithin the upper Hookton aquiferin the vicinity of the former wastewaterponds rangedfrom 0.001 to 0.002 ft/ft, while the vertical gradientsranged from 0.002 to 0.004 ftWft. The range of horizontalpermeabilityvalues for this aquifer, estimated by the tidal method, was 7 x 10. 5 to 2 x 10"3 cm/s, with most values being close to I x 10-3 cm/s. The range of verticalpermeability was estimatedas I x 104 to 4 x 104 cm/s Net horizontalflow velocities within the upper Hookton aquiferrange from 2 x 10-7 to I x 10-5 cm/s, while estimated vertical flow velocities ranged from 2 x 10.6 to 4 x 10'6 cm/s." (Ref. 7.19)
"Basedon a saturatedthickness of approximately25 ft for the upper Hookton aquifer,the range of transmissivity values is 0.04 cm2/s to 1.21 cm 2/s. Estimated storativityvalues were all in the 104 range."
In summary, upon breach, the fuel pool water level will equilibrate to the water table depth. This is assumed in previous calculations and in this calculation to be the perched water table depth. In addition, the perched water table and the Upper Hookton aquifer are influenced tidally. This will result in filling and draining of the breached Spent Fuel Pool with each tidal cycle. The perched water above the first clay layer discharges to the local canals and marshes. The Upper Hookton aquifer in the sand material below the Ist clay layer discharges to Humboldt Bay or the Pacific. 8 This value was used as the Hydraulic Conductivity for the Saturated Zone in the Groundwater Transport-Saturated Zone input form. Further explanation is provided below Table 8 in Section 4.9. 9 A hydraulic gradient of 0.003 is used for the well and surface water body in the Groundwater Transport-Saturated Zone input form
TSD # 09-020 Revision 00 Page 28 of 73 4.6 Humboldt Bay Humboldt Bay is a tidal bay receiving and discharging ocean water through its inlet. Humboldt Bay is divided into an Entrance Bay extending from Buhne Point to the mouth of the Elk River; a South Bay, south of Buhne Point; and a North Bay, north of the mouth of the Elk River and including Arcata Bay. Very little fresh water discharges into Humboldt Bay.(Ref. 7.19, 7.26) Humboldt Bay is a large, shallow body of water with deep channels. It is separated from the ocean by two long, narrow spits. The middle portion of the bay is joined to the ocean by a narrow channel passing between the north and south spits. The bay is approximately 23 km (14 miles) long, its width ranges from 0.8 km (0.5 miles) near its middle to over 3 km (2 miles) at the south end and 6 km (4 miles) at the north end, with an average depth of 12 ft mean lower low water (MLLW).(Ref. 7.19, 7.26) It is 28 km2 (11 mi 2) at the mean lower low tide (MLLW).(Ref. 7.26)
* , ,, -, : ***- : / 11'" 20xomWEe5.* .
.... . I I. 1 . ." .. 'r ..... "..
"t... "
r -O A Figure 12 - Topography of Humboldt Bay Area The tides of Humboldt Bay are of moderate height. The mean and diurnal tide ranges are 4.3 ft and 6.2 ft (1.3 and 1.9 m) at the entrance, 4.8 ft and 6.6 ft at Hookton Slough, and 5.0 ft and 7.0 ft at Arcata Wharf. Because the bay is so shallow, its tidal prism is large in comparison to its low-tide volume. The average volume of the tidal exchange from a higher high to a lower low tide amounts to approximately 61,000 acre-ft, (7.5E+7 M3) or 44 percent of the mean higher high tide volume.(Ref. 7.26) The mean higher high tide volume is thus 138,636.4 acre-ft or 1.70E+8 M3 . Since this water is replaced by the subsequent tide, water quality conditions in the ocean have a considerable influence on water quality and ecological characteristics of the bay.(Ref. 7.19) The tidal dilution calculation for the discharge canal used a conservative near field volume of 3.33E+510 cubic meters.(Ref. 7.29) It is anticipated that the groundwater '0A near field volume of 3.33E+5 cubic meters was used for the calculation as opposed to the much higher volume for the bay.
TSD # 09-020 Revision 00 Page 29 of 73 discharge into the bay will be more diffuse and extend over a larger area than the more limited near'field area at the mouth of the discharge canal. The Bay is 420 feet (128 meters) from the Spent Fuel Pool (Ref 7.17, 7.18) The decommissioning environmental report (Ref. 7.26) states, "To determine the flushing action of the tides, area capacity curves were made of the bay for each tide level. An examination of these curves showed that, on an average, twice during a 24 hour period"1 , replacement water would be:
- Entire Bay41%
- South Bay 52%
- North Bay 44%
- Entrance Bay 23%
4.7 Postulated Release to Groundwater In this scenario a heavy load traversing the fuel pool, is dropped into the cask pit, creating a breach in the cask pit floor and tremie concrete (see Figure 5and Figure 6). The turbulence caused by the force of the drop would suspend most of the sludge in the water. Water would initially drain to the level of the water table. Itwould then continue to drain eventually to the level of the initial low tide water table level. The previous bounding calculations used a mean low level water table at 9 foot elevation in the winter rainy season and at 6 foot in the dry summer season.(Ref.(Ref. 7.17, 7.18). Evaluation of Monitoring Well 1 data in Figure 11, shows the water table below Unit 3 is fluctuating between the 4.5 foot and 7.5 foot elevation in response to the tidal cycle. Thus assuming the breach occurred in the summer season and that the water level in the pool is at the 10 foot elevation, approximately 5.5 feet of water would drain from the pool to equilibrate with the bottom of the tide water table at elevation of 4.5 feet. This initial water loss would disperse and co-mingle with the groundwater below the fuel building. The pool would then refill on the high tide cycle to the 7.5 foot elevation, diluting the radionuclide concentrations in the pool with the incoming water. Draining, refilling, dilution and release of the pool would continue on each tidal cycle until the pool concentrations equilibrate with the groundwater concentrations. The calculated concentration from a well at downgradient edge of the contaminated zone after the initial breach is 0.0486 times the initial pool concentration. If it is assumed that the pool water concentration is diluted to 0.486 times the concentration in the groundwater below the pool and that the pool refills to 7.5 feet with groundwater, the dilution and resulting concentration can be calculated for each tidal cycle. The predicted concentration change over time in the fuel pool is shown in Figure 13. '1 Previous calculations did not consider dilution due to tidal flushing. RESRAD-OFFSITE incorporates annual flushing into the model, the entrance bay daily volume exchange of 23% was applied to the near field volume of 3.33E+5 cubic meters in the model.
TSD # 09-020 Revision 00 Page 30 of 73 ( Fuel Pool Concentration 6,000 - A0 -* =*, Co-60 5,000 7\ Sr-90 400-Cs-137 3,000 2,000 200
"ýW A.~
0 :O 20 30 40 Days Post Breach Figure 13 - Pool Concentrations Days Post Breach Under this scenario the entire overall source term would enter the course sand of the aquifer over a 20 to 40 day period. The minimum volume of Upper Hookton aquifer sand that could be contaminated by the water released can be calculated based upon the void space in the soil. The course sand of the aquifer has an effective porosity of 0.25 as shown in Table 8. Effective porosity is defined as "The effective porosity,Pe, also called the kinematic porosity, of a porous medium is defined as the ratio of the part of the pore volume where the water can circulate to the total volume of a representativesample of the medium."(Ref. 7.20) Thus the minimum volume of the contaminated area of the aquifer is the volume of the water in the pool divided by the effective porosity of the sand. This assumes the sand is dry. This volume is 1.56E+6 liters (e.g., 1.56E+3 mi3). This is equivalent to a block of contamination 11.6 meters or 30.06 feet in length, width and height. As seen in Figure 8 and in the discussion below it, the Upper Hookton deposits are sandwiched between two alluvial clay deposits and are only 24 to 40 feet thick.
TSD # 09-020 Revision 00 Page 31 of 73 Thus a 30 foot block of contaminated material would effectively strata of the Upper Hookton aquifer. Drawing 55428 shows the stratigraphy for the soil adjacent to the reactor caisson. This drawing was edited and is provided in Figure 7. This figure shows that the aquifer is covered by clay and soil deposits. The top of the course sand in the Upper Hookton is at elevation 19 feet 4 inches below grade (Elev.12 ft). Thus the release from a fuel pool breach would result in contamination being localized 19 feet below grade in the Upper Hookton aquifer. 4.8 RESRAD-OFFSITE Model of Release As described in Section 3.2, nine exposure pathways may be considered in RESRADOFFSITE:
- direct exposure from contamination in soil,
- inhalation of particulates and radon, 0 ingestion of plant foods, 0 ingestion of meat,
- ingestion of milk,
- ingestion of aquatic foods,
- ingestion of water, a and incidental ingestion of soil.
Since a fuel pool breach would result in subsurface introduction of contamination 19 feet below grade, direct radiation exposure, soil ingestion, and inhalation are not viable pathways. In addition, contamination of plant foods, meat and milk from such a release are unlikely due to the clay like nature of the upper strata and poor communication between the perched groundwater and the aquifer as described in Section 4.4 and Section 4.5. As noted previously, the brackish water is not a viable freshwater aquifer for irrigation or a source of potable water. In addition, as noted earlier in Section 4.4 there is little vertical flow within the Upper Hookton aquifer. Therefore contamination injected 5.88 meters (e.g., 19' 4").below grade would not be expected to disperse vertically and become available for uptake in the meat, milk, fruits and vegetable pathways. Vertical gradients range from 10 to 20 ft/mile (0.002 to 0.004 ft/ft). The injection occurs at 19 feet, and the bay is 420 feet down gradient. Therefore, as was the case in previous evaluations, the only viable12pathway is from ingestion of aquatic foods such as fish, crustacea, and mollusks from the bay. RESRAD software models migration of radionuclides using various soil "Zones". As seen in Figure 14 from the RESRAD Version 6 User's Manual (Ref. 7.22), the RESRAD model assumes radionuclides are driven into the aquifer by leaching from a contaminated zone, passing through an unsaturated zone and then into the "Saturated Zone" or aquifer. In order to emulate the fuel pool breach no cover material is assumed over "Contaminated Zone." A 19' 4" (5.88 meter) thick contaminated zone, and very thin, 0.01 meter, unsaturated zone are used. This models the "contaminated zone" as sitting directly on top of the Upper Hookton aquifer. The Contaminated Zone extends from the 12 foot elevation (e.g., grade level) to the -7 foot elevation where the lourse sand deposits of the aquifer are found. The average annual rainfall values for Humboldt County is 38.7 inches (0.983 meters) per year 100 year average Eureka.(Ref. 7.19) Zero runoff is specified for the contaminated zone and all erosion related 12 All pathways in RESRAD-OFFSITE were turned off except for the aquatic foods pathway. The groundwater pathway was turned on for calculation of groundwater concentrations via the well at various locations.
TSD # 09-020 Revision 00 Page 32 of 73 parameters are set to zero. 13 This maximizes the rainfall entering the soil and driving contaminants to the aquifer. This approach simulates the injection of the radionuclides directly into the aquifer from the contaminated zone in much the same manner as would be expected from a fuel pool breach. The "Contaminated Zone" and "Unsaturated Zone" parameters are chosen to model the rapid release or "breakthrough" of source term into the aquifer or "Saturated Zone" in a manner that emulates the release of radionuclide from the fuel pool due to tidal filling and draining as shown in Figure 13. Precipitation Radlonuclide Paths
*-,-t nd~frFlOW
- -~
saturated Zone (Aquifer) I. ~ I - Figure 14 - RESRAD Surface Water Pathway 13 See Attachment D for all parameter settings used in the RESRAD-OFFSITE model and the basis for them.
TSD # 09-020 Revision 00 Page 33 of 73 Flux in Primary Contaminatio
'00 Partially Saturated Flux out Flux out Saturated zone
- / Pulse in Concentration in Well Water Figure 15- RESRAD-OFFSITE Conceptualization of Groundwater Transport By setting the contaminated zone and unsaturated zone distribution coefficients (Kd's) very low at 0.001 and the b parameter at 0.01, the model assumes minimal retention of the radionuclides in the contaminated zone and unsaturated zone soils. Very low field capacity values of 1.OOE-5 are specified for the contaminated and unsaturated zones. The field capacity is the volumetric moisture content of soil at which (free) gravity drainage ceases. This is the amount of moisture that will be retainedin a column of soil againstthe force of gravity.
The field capacity is one of several hydrogeologicalparametersused to calculate water transportthrough the unsaturatedpart of the soil. Acceptable input ranges are from I E-5 to 1.(Ref. 7.21) Use of this low value maximizes input to the Saturated Zone aquifer below. The hydraulic conductivity of contaminated zone and unsaturated zone are set at 1.OOE+09 meters/year. This is the measure of the soil's ability to transmit water when subjected to a hydraulicgradient. The hydraulic conductivity depends on the soil grain size, the structure of the soil matrix, the type of soil fluid, and the relative amount of soil fluid (saturation)present in the soil matrix. The default value is 10. The manual states that the accepted range is 1 E-3 to IE+10.(Ref. 7.21) The Unsaturated Zone hydraulic conductivity is set at 1.OE+6. Using these parameters yields a rate of injection into the aquifer that closely approximates the fuel pool breach. As seen in Table 1, the calculated combined volume of the Fuel Pits and Cask Pit is 13,730 cubic feet or 3.88E+8 ml. A contaminated zone that is 29.0 feet (8.84 meters) in length, 24.53 (7.48 meters) 14 wide, and 19.3 feet (5.88 meters) deep yields a volume of 13,730 cubic feet (3.888E+08 ml). By setting the density of the contaminated zone to I g/ml 4, the calculated overall fuel pool concentrations in Table 7 can be input as the soil concentration in pCi/g for the contaminated zone. As seen in Figure 16, this yields a loss of source term from the contaminated zone that closely approximates the reduction in fuel pool concentrations shown in Figure 13. 14 These values are used for the Contaminated Zone in the RESRAD-OFFSITE Physical and Hydrological-Contaminated Zone and Cover input form.
TSD # 09-020 Revision 00 Page 34 of 73 . REARAD Contaminated Zone Concentrations with b Parameter at 0.01 and Contaminated Zone and Unsaturated Zone Kd's at 0.001 6000 5000
--- Co-60
--- Cs-137 4000 S 3000 W
2000 (. 1000 0 10 20 30 40 Days Post Breach Figure 16 - RESRAD Offslte Predicted Contaminated Zone Concentrations Days Post Breach This model is very conservative assuming the entire overall source term of the fuel pool is eventually released to groundwater. The model assumes that 100% of the source term is soluble in the water. It should be noted that the vast majority of the source term in Table 7 is contained in the sludge. The sludge consists of debris such as dust and oxides formed from corrosion such as crud as well as the uranium oxides from failed fuels. Fuel crud consists mainly of iron oxide and a small fraction of other metal oxides (e.g. Me: Ni, Cr, Mn, Co, Cu and Zn), depending on the corrosion rates of different materials and the water chemistry used. For BWR fuel crud, the main phases are hematite and nickel ferrite spinels.(Ref. 7.13). Fuel crud from disposed BWR fuel rods usually has a flaccid reddish or black appearance. The primary source of crud is the corrosion products of stainless steel in the feed water system. In early BWRs, corrosion of copper alloy preheaters used in the feedwater system led to the introduction of copper and nickel into the primary system at nearly the same rate as that of iron. The phase compositions of crud, as determined by X-ray powder diffractometry, are (.
TSD # 09-020 Revision 00 Page 35 of 73 mainly red hematite (a-Fe 20 3) and black spinels of type MxFe 3 _xO4 (x=0 - 1; M=Ni, Zn, Cr, Mn, Co and Cu). The color appearing on the fuel rod surface may reflect, to some degree, the phase composition of fuel crud.(Ref. 7.13) Thus the high Fe-55, Co-60 and Ni-59, N-63 are nickel, are in the oxidized hematite and spinels from fuel crud. In general, the particle size of crud is in the range of 0.1 to 2 pm .(Ref. 7.13) Hematite and spinel species are relatively insoluble and resistant to weathering.(Ref. 7.16) The high transuranic concentrations are from failed fuel where cladding was breached releasing the irradiated fuel material. Studies of transuranics in N Reactor Spent Fuel Pool sludge at Hanfordfound that "thatplutonium and particularlyamericium are trace constituents in the uranium matrix and that both are readily incorporatedinto U0 2, the primary uranium metal corrosionproduct." The N reactor used a uranium metal fuel, but once exposed to water it quickly corrodes to uranium oxide.(Ref. 7.15) Separation of the americium orplutonium from their strong associationin the parent uranium matrix would require dissolution of the uranium matrix with the associatedplutonium and americium. Uranium dioxide and other uranium phases found in the sludge are only soluble in water under acid conditions (pH below 1) or under conditions that are both oxidizing (e.g., aerated)and containinghigh carbonate concentrations....... Being negligibly soluble, the Pu02 and Am0 2 will tend to remain with the poorly soluble uranium phases, even as subsequent U0 2 oxidation to the slightly more soluble U(VI) compounds occurs. On these bases, the plutonium and americium are expected to stay with the solid phase uranium and their concentrationsrelative to uranium remain unchanged from that of the starting fuel. In particular,the americium is expected to be distributed within the corroded fuel matrix and exhibit the same solubility characteristicsas the bulk uranium and plutonium and not show the solubility of pure americium phases in both the as-settledsludge and in the Sludge Treatment Project (STP) processpost-corroded sludge.(Ref. 7.14) The model is therefore very conservative because it assumes rapid flushing and thus high concentrations of radionuclides into the aquifer. In reality crud and uranium oxides in the sludge have low solubility or they would have been dissolved in the fuel pool. They would be filtered the sand and accumulate in the soil adjacent to the breach. This is therefore a very conservative model that assumes high mobility within the course sands of the aquifer. This approach will bound and address any concerns regarding enhanced transport through colloids or chelation. 4.9 Fish Pathway Model Upon release to the Upper Hookton aquifer, radionuclides are transported to Humboldt Bay or the Pacific Ocean. The fish pathway in RESRAD-OFFSITE calculates equilibrium surface water concentrations using the water transport model. Bioaccumulation factors in pCi/kg per pCi/L water are then used to calculate the radionuclide concentrations in edible aquatic foods such as fish, crustaceans, and mollusks. The bioaccumulation factors used are found in TABLE 2-6 of the RESRAD-OFFSITE User's Manual (Ref. 7.21). The radionuclide concentration in the aquatic foods is then converted to an annual intake of activity by multiplying the concentration times the average annual consumption of that food type for the individual. The Regulatory Guide 1.109 (Ref. 7.1) Table E-5 annual consumption rates for an adult were used for the fish pathway rather than the RESRAD default values. An annual
TSD # 09-020 Revision 00 Page 36 of 73 consumption of 21 kg/year1 5 for fish and 5 kg/year' 5 of other aquatic foods such as crustaceans and mollusks was used in the model. These are more conservative than the RESRAD default values. Dose conversion factors (DCFs) are used to convert ingested radionuclide activity to dose. The default RESRAD-OFFSITE dose conversion factors from Federal Guidance Report 11 (FGR 11) were used for these calculations.16 The bay is modeled as surface water due north of the fuel pool. A point worth noting is that the RESRAD-OFFSITE "Site Layout" input form and "Groundwater Transport" input form use different distances to the Surface Water body. As seen in Figure 17, the "Site Layout" input form considers the distance to surface water body to be from the upgradient edge of the Contaminated Zone. As noted in Section 4.6, groundwater empties into the Bay 420 feet (128.6 meters)1 7 from the Spent Fuel Pool (Ref 7.17, 7.18). The "Groundwater Transport" input form, however, requires the distance to the Surface Water body from the downgradient edge of the Contaminated Zone. As noted in Section 4.8 and Footnote 14, a Y axis width of the Contaminated Zone is 7.48 meters. So the distance to the Surface Water for the "Groundwater Transport" input form is 128.6 - 7.48 = 120.5 meters 17 Y axis L. Laiger.Y ..o.......di
.. e..y. coordinate ..t..o..f.s.
of offsitej...a.r..e.a.... area ____ Smaller. coordinate of offsite area___( Y dimension of .. primary contamination, (0,0) X axis O- X dimension of primary contamination Smaller X coordinate of offsite area Larqer X coordinate of offsite area Figure 17 - RESRAD-OFFSITE Site Layout Coordinates The fish pathway uses a conservative near field volume of 3.33E+5cubic meters'8 as the surface water volume.(Ref. 7.29) and assumes a 23% daily replacement volume for the Entrance Bay Area as noted in Section 4.6. This equates to an annual flow quantity of 2.8E+7 cubic meters/year (e.g., 0.23 x 3.33E+5 cubic meters x 365 days/year). The mean residence time of the surface water is the ratio of the surface water body volume to the annual flow Annual fish consumption of 21 kg/year and aquatic foods consumption 5 kglyear were used in the RESAD OFF-SITE Model 16 The Dose Conversion Factor Library to be used is specified RESRAD-OFFSITE-Change Title input form. 17 Distance to the surface water in Site Layout input form is 128 meters, distance from down gradient edge of contaminated zone in Groundwater Transport input form is 120.5 meters. 1 Used as surface water volume of surface water body on Groundwater Transport-Surface Water Body input form.
TSD # 09-020 Revision 00 Page 37 of 73 quantity. This provides a mean residence time of 0.084 year' 9 . Thus the model does not take credit for dispersal throughout the entire bay over the course of a year. This would be based upon a 44% daily replacement volume. All radionuclides in the Contaminated Zones and Unsaturated Zones were assigned distribution coefficients ( Kds) of 0.001 and b parameter values of 0.001 in order to emulate the rapid release of source term to the Upper Hookton aquifer. The SAFSTOR Safety Evaluation Report (Ref. 7.18) used the hydrogeological parameters shown in Table 8 for estimating groundwater concentrations at various distances from the fuel pool and rates of travel as the plume migrates toward the bay. Table 8 - Hydrologic Parameters used by Current SER Parameter Value Units Value Units Mean Tide Level 3.3 ft 1.006 meters Groundwater Elevation 6 to 9 ft 1.8 to 2.7 meters Hydraulic Conductivity K 10,400 ft/yr 3.170E+03 m/yr Effective Porosity 0.25 0.25 Total Porosity 0.4 0.4 Longitudinal Dispersion 1 ft 3.048E-01 meters Lateral Dispersion 0.5 ft 1.524E-01 meters Distribution Coefficient Cs 20 ml/g 20 ml/g Distribution Coefficient Sr 0.4 ml/g 0.4 ml/g Distribution Coefficient Co 1 ml/g I ml/g As seen in Figure 18 and Figure 19 the hydraulic conductivity used in the SARSTOR fuel pool breach calculation are consistent with the values anticipated for sand in the RESRAD Data Collection Handbook (Ref. 7.20). If the lower hydraulic conductivity of 3.15 meters per year noted for the Upper Hookton sand deposits underlying the 1 st clay layer is applied, RESRAD-OFSITE provides thefollowing message, "Under the specified hydrologicalconditions the recharge through the primary contaminationis 64.9991037792915cubic meters peryear. The ground water flow rate underthe primarycontaminationis only 0. 6729308 cubic meters per year. Please adjust surface hydrologicalinputs and/orthe thickness of the saturatedand unsaturatedzones to ensure that the ground waterflow under the primarycontamination exceeds the recharge through the primarycontamination."Therefore, the rapid flushing that drives the nuclides from the Contaminated Zone into the Saturated Zone and simulates the release from the Spent Fuel Pool cannot be modeled using the lower hydraulic conductivity value. The same higher hydraulic conductivity value that was used in previous calculations 10,400 ft/yr (3.170E+03 m/yr) was used for this calculation rather than the lower 3.15 m/yr value. The lower hydraulic conductivity would result in a less conservative estimate of dose due to the extended time to migrate to the bay and the intervening radioactive decay. If the hydraulic conductivity in the Upper Hookton is 3.15 m/yr the years in which the peak doses occur would be much further in the future than predicted in this evaluation. '9 Used as mean residence time in Groundwater Transport-Surface Water Body input form.
TSD # 09-020 Revision 00 Page 38 of 73 ( Saturated Hydraulic Soil q\" Crndgirfi-,hV- K".... l(nm/x Unconsolidated deposits Gravel 1 xx I04. 1 102. 1 1 xx 107 IO0 Clean sand 1 x 101 - i X 105, Silty sand Silt, loess I x 102 - i x 102 Glacial till 1 x 10 1x 10, 2 Unweathered marine clay 1x 10lx 10-o Rocks Shale I X 10-7 . I x 10"2 Unfractured metamorphic and igneous rocks I X10"3 - lx 103 Sandstone 1 x 10.3 - I X 101 Limestone and dolomite 1 x 10- - 1x 101 Fractured metamorphic and igneous rocks I x I01 - I x 1Os (. Permeable basalt 1 x 101 - I x i01 Figure 18 - Range of Saturated Hydraulic Conductivities for Soils Saturated Hydraulic Conductivity, Texture K (-m,/yAL Sand 5.55 x10 Loamy sand 4.93 x 10-Sandy loam .1.09 x i03 Silty loam 2.27 x 102 Loam 2.19 x 102 Sandy clay loam 1.99 x 102 Silty clay loam 5.36 x 10O Clay loam 7.73 x 10' Sandy clay 6.84 x 10-Silty clay 3.21 x 10' Clay =405>x101 Figure 19 - Hydraulic Conductivities for Various Soil Textures
TSD # 09-020 Revision 00 Page 39 of 73 As seen in Figure 20 the total porosity and effective porosity in Table 8 are consistent with the values for course sand provided in the RESRAD Data Collection Handbook (Ref. 7.20). Course sand is the soil type in the Upper Hookton aquifer. Total Porosity. Pt Effective Porositya P, Arithmetic Arithmetic Material Ilange Men RangN Mean Sedimentary material Sandstone (fine) .b 0.02 w0.40 0.21 Sandstone (medium) 0.14- 0.49 0.34 0.12- 0.41 0.27 Siltstone .0.21- 0.41 0.85 0.0170.33 0.12 Sand (fine) 0.25- 0.53 .0.43 0.01- 0.46 0.33 Sand (medium) 0.16- 0.46 0.32 Sand (coarse) 0.31 - 0.46 0.39 .0.18- 0.43 0.30 Gravel (fine) 0.25- 0.38 0.34 0.13- 0.40 0.28 Gravel (medium) - 0.17- 0.44 0.24 Gravel (coarse) 0.24 - 0.36 0.28 0.13- 0.25 0.21 Silt 0.34 - 0.51 0.45 0.01 - 0.39 0.20 Clay 0.34- 0.57 0.42 0.01- 0.18 0.06 Limestone 0.07 - 0.56 0.30 - 0.36 0.14 Wind-laid material Loess - 0.14- 0.22 0.18 Eolian sand , 0.32a0.47 6- 0.38 Tuff 0.02 -0.47 0.21 Igneous rook Weathered granite 0.34- 0.57 0.45 Weathered gabbro 0.42- 0.45 0.43 Basalt 0.03 - 0.35 0.17 Metamone-hic rock Schist 0.04 - 0.49 0.38 0.22.0.33 0.26 a Effective porosity is discussed in Section 4. A hyphen indicates that no data are available. Source: McWorter and Sunada (1977). Figure 20 - RESRAD Data Collection Handbook Total Porosity and Effective Porosity Values for Soil Types The Saturated Zone distribution coefficients (Kds) shown in Table 8 were used for Co-60, Cs-137, and Sr-90. The basis for the assigned Kds for other dose significant nuclides are discussed below in Section 4.10. A Saturated Zone Kd value of 10 was assigned for Plutonium and all other nuclides were assigned a Kd of 20.
TSD # 09-020 Revision 00 Page 40 of 73 4.10 Saturated Zone Distribution Coefficients for I Americium, Plutonium, and Curium The distribution coefficients used for all radionuclides in the model are provided in Attachment D, RESRAD-OFFSITE Input Parameters. The distribution coefficients for Co-60, Cs-1 37 and Sr-90 are provided in Table 8 and are the same as those used in the previous fuel pool accident calculations. As discussed in Section 4.4, these Kds are reasonable and conservative values for the brackish-water course sand aquifer of the Upper Hookton aquifer. Carbon 14 is assigned the RESRAD default Kd of zero as is tritium. As seen in Table 9, americium and plutonium radionuclides are also responsible for the majority of the radiation dose in the fish pathway. Therefore the range of Kd values and their basis is provided below. 4.10.1 Americium Americium readily sorbs to soil, mineral, and crushed rock materials, and exhibits high Kd values. Americium is therefore generally considered to be immobile in soil environments. Americium is a transuranic (actinide) element, and can exist in the +3 oxidation state in natural waters. In moderately to highly acidic conditions dissolved americium III (Am(II)) is present primarily as the uncomplexed cation Am 3'. In near neutral to alkaline pH conditions, americium forms aqueous americium carbonate complexes, such as Am(CO 3) 33 which are increasingly important with increasing concentrations of dissolved carbonate at these pH conditions.(Ref. 7.25) As seen below in Figure 23 in Section 4.4, the pH of the Upper Hookton aquifer is essentially neutral. Therefore, Americium would be expected to form carbonate complexes under these conditions. Concentrations of dissolved americium may be controlled by precipitation of hydroxide or ( carbonate solids in some systems.(Ref. 7.25) Concentrations of dissolved Am(Ill) in soil environments may be controlled by the precipitation of solids such as Am(OH) 3 and AmOHCO 3, and Am2(CO 3)3, especially at near neutral and alkaline pH conditions (Felmy et al., 1990; Vitorge, 1992; Silva, 1984; and others).(Ref. 7.25) 100 AmCO3÷ Am(CO3)2 0 80 Am3Am 60 20 - -A "SO/ AmOH 0 3 4 5 6 7 8 9 10 pH Figure 21 - Thermodynamic Predicted Speciation of Americium at Various pH Values As shown in Figure 21, at pH 7 the dominant species is a cationic carbonate complex AmCO 3+. For the pH range from 4 to 10, it is suggested that a Kd of 4 mllg be used as a minimum Kd value for input
TSD # 09-020 Revision 00 Page 41 of 73 forming calculations of americium transport in soils. This value was reported for pH 7.8 by Routson et al.(1975, 1977) and is the lowest Kd value that they gave for experiments conducted with very to moderately dilute calcium and sodium electrolyte solutions. The other Kd valuesreported by Routson et al.(1 975, 1977) for these solution concentrations ranged from 6 ml/g at pH 6.2 to 1,200 ml/g at pH 4.1 and 7.4.(Ref. 7.25) 250,000 A
- 200,000 E
- 150,000 lOOO0OAA S100,000 A "C)
E AA
< 50,000 0
4 5 6 7 8 9 10 pH Figure 22 - Maximum Anticipated Am-241 Kds as a Function of pH The solid line segments in Figure 22 connects the maximum Kd values reported at pH values of 4, 6, and 10 by Sanchez et al.(1982). The Kd values corresponding to integer pH values between 4 to 10 are, respectively, 5,600, 16,500, 27,300, 76,700, 126,000, 176,000, and 225,000 ml/g based on straight line extrapolations between these 3 Kd values from Sanchez et al.(1 982). These values may be considered as conservative maximum Kd values for Am(Ill) adsorption on soil. Thus at a pH of 7, the minimum Kd would be 4 ml/g with a maximum Kd of 76,700 ml/g.(Ref. 7.25) Americium(Ill) is more mobile at low to moderate pH values where the net surface charge on minerals becomes more positive and in high ionic strength solutions. In addition, Americium has been found to be mobilized by colloids such as those of clay and humic acid. The water quality of the various strata in the Unit 3 area are provided in Figure 23. The Upper Hookton aquifer has nearly neutral pH with high conductivity and high ionic species concentrations such as Sodium, Sulfates and Chlorides. As noted above, these water quality characteristics have bearing on the speciation and sorption on soil of radionuclides that influence the distribution coefficients Kds that can be expected.
TSD # 09-020 Revision 00 Page 42 of 73 PERCHED GROUNDWATER ZONE (A) IN UPPER HOOKTON SILTS AND CLAYS South of Unit 3 WCC85.2A WCC85.3A Parameter 8/15185 08o15/85 pH 5.9 6.4 Conductivity 2590 2830 TDS 1510 1620 Sulfate 248 87 Chloride 450 780 Sodium 430 300 PERCHED GROUNDWATER ZONE (A) IN HOLOCENE SILTS AND CLAYS South of Unit 3 WCC85-4A WCC8S-IOB jPlram eter.. ................................
...081&/5/85 pH 6.8 7.0 Conductivity 5220 6680 ToS 3410 3090 Sulfale 420 405 Chloride 1560 1280 Sodium 780 1000 PERCHED GROUNDWATER ZONE (B) IN HOLOCENE BAY DEPOSITS Wastewater Pond Site WCC85-MD WCC85.7B WCC855-B Parameter 08!85 0846/856 081"6185 pH 6A, 5,7 6.7 Condluctivity 8900 1 1100 17300 TDS 288 358 9870 Sulfate 1450 1190 987 Chloride 1850 3500 4650 Sodium 1200 2000 1900 UPPER HOOKTON AQUIFER (
Southeast of Unit 3 DER85-1 DERS54 DER85-5 DER85-7 DER86-8 DER85.10 Pram.ter -04111185 04111185 041111815 04/11185 04111185 4t1111985 pH 7.0 6:0 7.2 7.0 7.1 7.2 Conductivity 108 2363 5038 13022 9048 25776 TDS Sulfato 49 23 67 77 174 :103 Chloride 200 640 1990 4550 3010 9050. Sodium 150 370 1000 2600 2000 5600 LOWER HOOKTON AQUIFER PG&E Water Supply Wells Well No, i Well No. I Well No. 2 Parameter 1111 8M3 02/24194 02)24/94 pH 7.4 7T8 7.7 Conductivity 140 200 150 TDS 130 130 tOO Sul fate 1.9 5.8 4.3 Chloride 12 26 13 Sodium 12 18 i1 Note: 1. pH is in pH units; conductivity is in micromhos-Icrn, and others are ppm.
- 2. See Figures 2.5.1, 49, -12, -13 for location of wells.
Figure 23 -Water Quality Data for Groundwater The salinity in the Upper Hookton aquifer as measured by the conductivity ranges between 1,100 and 26,000 micromhos/cm and chloride ranges from 200 to 9,000 ppm. The lowest conductivity readings, 1,000 to 2,500, are south of Unit 3. The conductivity is higher around the wastewater pond site where the conductivity is 5,500 to 26,000, probably reflecting salt water intrusion from the marshes in this area.(Ref. 7.19)
TSD # 09-020 Revision 00 Page 43 of 73 Studies of Americium Kd's in marine estuaries where high salinity and brackish water conditions are encountered yielded Kds in the 104 to 10 range.(Ref. 7.25) But these may have been in silt with high organic content. The Kd values have also been shown to decrease with. increasing concentrations of dissolved calcium and sodium. Course sandy soils from Washington state were investigated, the Kd values were >1,200 ml/g, and were independent of the concentrations of dissolved calcium and sodium. Their calculated Kd values ranged from 1,200 to 8,700 ml/g this was greater than anticipated by the researchers.(Ref. 7.25) K.d alues (ml! g) Soil Type Geometric Number of Mean Observations Range Sand 1,900 29 8.2 - 300,000 Silt 9,600 20 400 -48,309 Clay 8,400 11 25 - 400,000 Oig*uiic 112,000 5 6,398 - 450,000 Figure 24 - Range of Americium Kds for Various Soil Types Listed by Thibault et al.(Ref. 7.25) The RESAD-OFFSITE default Kd for Americium is 20 ml/g. This is at the lower end of the potential Kds that could be expected for course sandy soil at a pH of 7. Given the above discussion concerning sodium ion competition, clay colloid mobilization, and lower KdS in high ionic strength solutions, this Kd is appropriate for the course sand brackish water conditions of the Upper Hookton aquifer which is bounded at the top and bottom by clay deposits. 4.10.2 Curium Curium is a transuranic (actinide) element, and can exist in the +3 oxidation state in natural waters. Cm(lIl) geochemistry is expected and widely accepted to be very similar to that of Am(Ill) and trivalent lanthanide elements, such as europium (111), Eu(lll). Compared to other actinides, Cm(lll) and Am(Ill) are considered to be immobile in soil environments, and both exhibit high Kd values. Figure 25 indicates that curium can exist as several aqueous species at a neutral pH.(Ref. 7.25)
TSD # 09-020 Revision 00 Page 44 of 73 ( 100 C 80
-o 60 40 2-20 0
3 4 5 6 7 8 9 10 pH Figure 25 - Calculated Distribution of Cm Aqueous Species Using MINTEQA2 Thermodynamic Database Available curium sorption studies indicate that sorption of curium is strongly pH dependent and increases with increasing pH with peak adsorption occurring between pH values of 5 and 6. The observed pH dependence is expected, because the dominant aqueous species of curium in the pH range of natural waters are primarily cations such as Cm3+ and Cm(lll) carbonate complexes at acidic and basic pH values, respectively.(Ref. 7.25) The limited number of Kd adsorption studies for Cm(lll) in soils prevents calculation of Kd look-up tables. However, the sorption behavior of Cm(lll) is very similar to that of Am(IlI) (see Section 5.2) and trivalent lanthanide elements, such as Eu(lll). Guidance given above for Kd values for Am(Ill) in Section 5.2 can be used for input forming calculations of Cm(llI) migration in soils.(Ref. 7.25) K.. V...es (mvug) Soil Type Geometric Number of Mean Observations Range Sand 4,000 2 780- 22,970 Silt 18,000 4 7,666 - 44,260 Clay 6,000 1 Organic 6,000 1 Figure 26 - Curium Kd values (ml/g) listed in Thibault et al.(1990, Tables 4 to 8). The RESRAD-OFFSITE default Kd for curium is 1,378 ml/g. Because of the lack of pH specified Kds and the similarity of curium to americium the same low Kd of 20 was assigned for the Saturated Zone curium Kds. (
TSD # 09-020 Revision 00 Page 45 of 73 4.10.3 Plutonium In the ranges of pH and conditions typically encountered in the environment, plutonium can exist in all 4 oxidation states, namely +3, 4, +5, and +6. Under oxidizing conditions, Pu(IV), Pu(V), and Pu(VI) are common, whereas, under reducing conditions, Pu(lll) and Pu(IV) would exist. Dissolved plutonium forms very strong hydroxy-carbonate mixed ligand complexes, therefore, its adsorption and mobility is strongly affected by these complex species.(Ref. 7.24) Plutonium is known to adsorb onto soil components such as clays, oxides, hydroxides, oxyhydroxides, aluminosilicates and organic matter. Depending on the properties of the substrate, pH, and the composition of solution, plutonium would adsorb with affinities varying from low (Kd = 11 ml/g) to extremely high (Kd = 300,000 ml/g) (Baes and Sharp, 1983; Coughtrey et al., 1985; Thibault et al., 1990). Plutonium in the higher oxidation state adsorbed on iron oxide surfaces may be reduced to the tetravalent state by Fe(ll) present in the iron oxides. At pH values exceeding 6.5, the bulk of the dissolved plutonium (-90 percent) would be comprised of the Pu(OH) 2(CO 3) 22 - species with a minor percentage of Pu(OH) 4 " (aq). These illustrative computations indicate that, under pH conditions that typically exist in surface and groundwaters (>6.5), the dominant form of dissolved plutonium would be the tetravalent complex species, Pu(OH) 2(CO 3)22 . 100 30 s0 60 *Puoz* 20 l(P04- P(H0lq 0 3 4 5 6 7 8 9 10 pH-Figure 27- Calculated Distribution of Pu Aqueous Species Using MINTEQA2 Thermodynamic Database
TSD # 09-020 Revision 00 Page 46 of 73 Clay Content (wt.%) 0-30 31-50 51-70 Soluble Carbonate Soluble Carbonate Soluble Carbonate
* (meq/l) . (meqll) (Ineq/l)
Kd (nl/g) -0.1-2 3-4 1 5-6 0.1-2 3-4 1 5-6 0.1-2 3-4 5 Mininnun 5 80 130 380 1440 2,010 620 1,860 2,440 Mximumn 420 470 520 1.560 2.130 2,700 1,980 2,550 3,130 Figure 28 - Estimated range of Kd values for plutonium as a function of the soluble carbonate and soil clay content values Figure 28 shows that for low clay soils such as the course sand of the Upper Hookton, Kd can range from a low of 5 ml/g to a maximum of 520 ml/g. The REDRAD-OFFSITE default Kd for plutonium is 2000 ml/g. Given the above considerations, a.value of 10 ml/g is used as the Saturated Zone Kd for plutonium radionuclides.(Ref. 7.24) 4.11 Calculated Pathway Annual Doses Using these parameters and distribution coefficients for the other radionuclides the following doses were predicted for the fish pathway. ( Fish Pathway Summed Dose All Nuclides 0.25 0.2 0.15 (*0, E C9.05 0
-0.05 Years Post Breach Figure 29 - Temporal Graph of Fish Pathway Dose at various Aquifer Input Depths
TSD # 09-020 Revision 00 Page 47 of 73 The graph in Figure 29 shows that the highest dose in any one year occurs at year 250 and is about 0.24 mrem/year. This graph also shows that once the depth of the aquifer input to the surface water exceeds 14 meters, the calculated doses remain constant. RESRAD OFFSITE assumes a reflective aquitard that is twice the depth of the water table.(Ref. 7.21) As seen in Figure 7, this means the aquitard mirror is modeled at approximately 40 feet below the top of the Upper Hookton aquifer. Concentrations equalize across the aquifer using this method due to reflection off the lower aquitard. The RESRAD-OFFSITE manual states "Dispersionis considered to be inactive in the vertical direction, if the concentration profile in the vertical direction becomes essentially uniform because of repeated reflection of the plume by the lower impermeable layer and the watertable. It is also inactive if a zero value is specified for the vertical-lateraldispersivity."(Ref. 7.21) Thus, groundwater concentrations calculated by RESRAD-OFFSITE are representative of those that would be anticipated in a semi-confined aquifer such as the Upper Hookton course sand aquifer. Table 9 shows the calculated peak dose for each radionuclide and the year in which it is predicted to occur. Peak doses include the contribution from the daughter radionuclides. The variance in the year in which the peak dose occurs for different nuclides is driven mainly by the distribution coefficient, which controls the rate at which the nuclide migrates through the aquifer. Nuclides such as H-3 and C-14 which have Kds of zero reach the bay within a few years. If the lower hydraulic conductivity value of 3.15 meters per year was used, breakthrough times to the bay would be much longer than those in this model. The table shows that the sum of the peak doses is 0.371 mrem/year. Thus, if all of the radionuclides reached the bay in the same year, the fish pathway dose would be approximately 0.4 mrem/year. Since it unlikely that all radionuclides would migrate at the same rate, the best estimate of the peak dose that would result in any one year is the 0.24 mrem value at 250 years. Table 9- Fish Pathway Peak Doses Contaminated Fuel Pool Zone Concentration Concentration %Peak Dose Peak 1 mrem/year Nuclide pCi/g Peak Dose Total Year per VCi/ml Ac-227 7.OOE+00 2.76E-06 0.00% 231.4 2.54E+00 Am-241 7.50E+02 0.187 50.49% 242.6 4.OOE-03 C-14 7.16E+00 1.85E-02 4.99% 3.0 3.86E-04 Cm-243 1.51E+02 7.22E-05 0.02% 234.4 2.08E+00 Cm-244 1.51E+02 8.36E-05 0.02% 128.4 1.80E+00 Co-60 5.22E+03 3.27E-02 8.80% 14.8 1.60E-01 Cs-137 1.22E+03 1.19E-04 Q.03% 234.4 1.02E+01 Eu-154 3.13E+01 9.65E-14 0.00% 217.2 3.24E+08 Fe-55 1.09E+03 2.03E-29 0.00% 179.9 5.36E+25 H-3 3.03E+01 0.000 0.00% 3.0 6.41 E+02 Ni-59 6.99E+01 0.000 0.00% 243.2 9.85E+01
TSD # 09-020 Revision 00 Page 48 of 73 ( Contaminated Fuel Pool Zone Concentration Concentration %Peak Dose Peak I mrem/year Nuclide pCi/g Peak Dose Total Year per ICi/mi Ni-63 1.08E+04 0.000 0.01% 240.3 2.39E+02 Pu-238 2.30E+02 0.011 2.87% 122.5 2.16E-02 Pu-239 1.32E+02 0.019 5.21% 123.1 6.82E-03 Pu-240 1.32E+02 0.019 5.16% 123.1 6.89E-03 Pu-241 4.13E+03 0.057 15.44% 236.1 7.20E-02 Sr-90 2.74E+02 0.026 6.95% 8.3 1.06E-02 U-233 2.34E-01 0.000 0.00% 244.4 8.87E-02 U-234 2.34E-01 0.000 0,00% 243.8 3.08E-01 U-235 6.45E-02 0.000 0.00% 244.4 9.42E-02 U-236 6.45E-02 0.000 0.00% 243.2 3.91 E-01 U-238 1.87E-01 0.000 0.00% 243.2 3.91E-01 Total Peak Dose 3.71 E-01 1.OOE+00 The last column in Table 9 shows the concentration in the fuel pool which results in I mrem/year through the fish pathway for each radionuclide. It can be seen that very high fuel pool concentrations would be required to reach the emergency planning protective action guideline (PAG) of 1000 mrem at the Site Boundary. This should help provide a basis for evaluating the off-site dose consequences as source terms in the fuel pool change over the course of the decommissioning, such as during reactor vessel internals segmentation. 4.12 Groundwater Concentrations Released to the Bay The radionuclide concentrations in groundwater entering the bay can be estimated by modeling a well down gradient at 119.5 meters from the Contaminated Zone. This will yield the calculated groundwater concentrations 1 meter before it enters the bay. Table 10 shows the peak concentration and the year in which it occurs for all radionuclides, including daughter nuclides. The MPC values are from the January 1, 1992, 10 CFR 20 Appendix B, Table 2 Liquid Effluent Values. If all the radionuclides reached the bay at their peak concentrations simultaneously, the sum of the MPC fractions would be 1.17. Thus there would be no significant environmental impact on the Bay. Table 10 - Calculated Groundwater Concentrations Entering Humboldt Say NRC NRC NRC NRC Max Limit Limit Max Limit Limit Nuclide Year JiCi/ml pCi/ml Fraction Nuclide Year pCI/mI pCilmI Fraction AC-227 252.7 3.22E-14 5&00E-09 6.45E-06 Pu-238 132.8 2.30E-09 2.OOE-08 1.15E-01 Am-241 257.8 8.88E-09 2.OOE-08 4,44E-01 Pu-239 134.1 3.76E-09 2.OOE-08 1.88E-01 Am-243 263.6 1.97E-14 2.OOE-08 9.87E-07 Pu-240 134.1 3.73E-09 2.OOE-08 1.86E-01 C-14 3.9 1.06E-08 3.00E-05 3.54E-04 Pu-241 128.9 2.19E-10 1.OOE-06 2.19E-04 Cm-243 253.9 4.08E-12 3.OOE-08 1.36E-04 Ra-226 264.3 4.72E-16 6.OOE-08 7.87E-09 K
TSD # 09-020 Revision 00 Page 49 of 73 NRC NRC NRC NRC Max Limit Limit Max Limit Limit Nuclide Year gic/ml IPCi/mI Fraction Nuclide Year OCi/ml pCi/mI Fraction Cm-244 248.8 1.23E-13 3.OOE-08 4.11E-06 Ra-228 265.5 1.18E-20 6.OOE-08 1.96E-13 Co-60 16.8 1.43E-07 3.00E-06 4.77E-02 Sr-90 9.0 9.32E-08 5.00E-07 1.86E-01 Cs-137 254.6 4.50E-11 1.OOE-05 4.50E-06 Th-228 265.5 1.17E-20 2.OOE-07 5.83E-14 Eu-154 235.9 1.45E-18 7.OOE-06 2,08E-13 Th-229 265.5 8.33E-14 2.OOE-08 4.16E-06 Fe-55 195.3 1.82E-33 1.00E-04 1.82E-29 Th-230 263.0 8.62E-15 1.00E-07 8.62E-08 H-3 3.9 3.75E-08 1.OOE-03 3.75E-05 Th-232 265.5 1.22E-20 3.00E-08 4.06E-13 Ni-59 263.6 1.01 E-09 3.00E-04 3.36E-06 U-233 263.6 3.38E-12 3.00E-07 1.13E-05 Ni-63 261.0 2.36E-08 1.OOE-04 2.36E-04 U-234 261.0 3.68E-12 3.OOE-07 1.23E-05 Np-237 260.4 9.15E-13 2.OOE-08 4.58E-05 U-235 263.6 9.33E-13 3.OOE-07 3.11E-06 Pa-231 265.5 5.20E-15 6.OOE-09 8.66E-07 U-236 263.6 9.35E-13 3.OOE-07 3.12E-06 Pb-210 264.9 3.72E-16 1.00E-08 3.72E-08 U-238 263.6 2.71E-12 3.OOE-07 9.02E-06 Po-210 1264.9 1 3.70E-16 I 4.OOE-08 I 9.26E-09 Total I 1.17E+00 4.13 Drinking Water Pathway As noted in Section 4.4, the Upper Hookton aquifer is a brackish water aquifer. The confined nature of the deeper, lower Hookton aquifer (the two PG&E industrial wells were artesian at the time of installation) also serves to protect this zone by preventing downward vertical migration of brackish water. The two potable water wells nearest the spent fuel pool were owned by PG&E. Well No. 1 is about 600 feet east of the site and Well No. 2 is about 2,980 feet southeast of the site. These wells, which were sampled quarterly for activity, provided onsite water supplies but are no longer used.(Ref. 7.18) The nearest potable water wells in use at present are south of the facility on the other side of Route 101. it is not feasible for radionuclides to migrate upgradient for this distance. The distance from the Contaminated Zone to the well is the "Distance in the Direction Parallel to Aquifer Flow from Contamination to Well:" on the REDRAD Groundwater Transport input form. The user's manual states, "This is the distance, in meters (m), along a groundwaterflow ine from the downgradientedge of the primarycontamination to the well. It is used in the computation of transportin the saturatedzone to the well. A negative value indicates that the well is either upgradientof or within the primary contamination.if this value is negative orif the combination of water and land usage and exposure pathways indicatesthat well water has no influence on dose, the computationalcode will skip the well water concentration computations."(Ref. 7.21) Thus upgradient concentrations cannot be calculated by RESRAD-OFFSITE. The ISFSI FSAR states (Ref. 7.19) "The Humboldt Bay Municipal Water District(HBMWD) provides water to residentialand industrialusers in the Humboldt Bay area. The district operatestwo separate water systems. Drinking water is supplied through the domestic water system. Raw water, used only for industrialpurposes, is taken directly from the surface of the Mad River and delivered, untreated,to industrialcustomers. HBMWD produces a capacity of 20 million gallonsper day of waterfrom five Ranney wells in the Mad River nearEssex. The
TSD # 09-020 Revision 00 Page 50 of 73 ( City of Eureka General Plan Background Report identifies three groundwaterwells located within 1 mile of the ISFSI site."
- 13. Domestic wells 12 A I!ndustria i/irrigation/monitoring wells Figure 30 - Excerpt from ISFSI FSAR Figure 2.5-1 Showing Nearest Domestic Wells to Site As seen in Figure 30 the interpolated distance based upon the key, which is 0.5 miles, to the nearest domestic water well is 0.58 miles or 934.5 meters. To evaluate worst case potential doses for the nearest Domestic Well, the fish pathway is turned off, such that only the water pathway is turned on, and the downgradient well was located 934.5 meters from the Spent Fuel Pool. As seen in Attachment B, the ingestion rates assumes 730 liters per of potable water from the well. This is the Regulatory Guide 1.109 annual drinking water ingestion quantity from Table E-5.(Ref. 7.1) This assumes that the domestic well is the only source of potable water. The water use parameters in the Groundwater Transport input form also assume that 225 liters per day is used in the indoor dwelling. As seen in Figure 31, the predicted maximum annual dose occurs at around 1000 years post breach and would result in a peak annual dose of approximately 0.85 mremlyear.
TSD # 09-020 Revision 00 Page 51 of 73 DOSE: All Nuclides Summed, All Pathways Summed 0.9 0.8 0.7 0.6 0* E 0.4 0.3 0.2 0.1 nn 0 1~z 500 1000 1500 IL 200 2500 3000 Years HUBOLDT-SFP FNALDoesic Wa~er.ROF 05Z 17:19 GRAPHICSASC IdnudesA Paftvays Figure 31 - Hypothetical Annual Doses if Nearest Domestic Water Well was Located Down Gradient This represents a worst case bounding dose which assumes the domestic water well is in ihe Upper Hookton aquifer, rather than the fresh water aquifer of the Lower Hookton and that the well is down gradient. There is no viable drinking water pathway. it is alsounlikely that a brackish water aquifer would be use for irrigation. 4.14 Potential Impact on Decommissioning The regulation 10 CFR 50.82(a)(6) states that the licensee must not perform any decommissioning activity that (1) forecloses release of the site for possible unrestricted use, (2) results in any significant environmental impact not previously reviewed, or (3) results in there no longer being reasonable assurance that adequate funds will be available for decommissioning.(Ref. 7.3) As noted in Section 4.8, 4.9, and 4.10 very conservative assumptions were made in this evaluation relative the amount of sludge and source term that would be dispersed below the Spent Fuel Pool in the Upper Hookton aquifer and the solubility and mobility of that material. It is unlikely that the entire sludge source term would be released to from the breach. It is also unlikely that the less soluble radionuclides such as the transuranics, would be released rapidly to the surrounding groundwater given the insoluble nature of the hematite, spinels and uranium oxides in which they are concentrated. A large fraction of the source term would be retained in the localized area under the spent fuel building with the insoluble sludge. In addition a very high hydraulic conductivity that was several orders of magnitude higher then the measured value of 3.15 meters/year for the Upper Hookton was used. This will also slow the dispersal of the material.
TSD # 09-020 Revision 00 Page 52 of 73 The material could be recovered by excavating the contaminated soil using equipment in the bottom of the spent fuel pool during the decommissioning. It is unlikely that the consequences of a breach would impact the 50.82(a)(6) criteria since soil decontamination equipment and associated personnel will be available to immediately initiate decontamination activities at the site. 5.0 Conclusion This evaluation did not find a condition or consequence that has not been previously evaluated or that is outside the licensing basis for Humboldt Bay Unit 3. A breach of the spent fuel pool would occur with trained radiation workers, supervision, and Health Physics technicians present. Due to the high water table, there would be no direct radiation levels that exceed those encountered during decommissioning activities as a result of the breach and lowering of the spent fuel pool water level. In addition, the materials and resources to contain, control, decontaminate and mitigate airborne and removable contamination that might result from a heavy load drop are available on site. There would be no on-site dose consequences that would lead to excessive personnel exposures or pose a risk to future decommissioning activities. Off-Site and environmental consequences due to a heavy load accident are likely to result from the release of the source term to the Upper Hookton aquifer. Due to the 19' 4" thick layer of material, which includes a 1jt layer clay aquitard and a lower Unit F Clay aquitard, which semi-confine the aquifer, the contaminants are likely to remain in the Upper Hookton brackish ( water aquifer until they are discharged to the Bay or the Pacific Ocean. Due to the 1t clay aquitard and depth at which the release would occur, the radionuclides are unlikely to migrate into near surface perched groundwater above it. Due to the Unit F clay aquitard below the Upper Hookton aquifer, migration to the Lower Hookton freshwater aquifer is also unlikely. Since the Upper Hookton aquifer is brackish water, there are no down gradient domestic water or industrial water wells. Thus the only viable off-site exposure pathway is through consumption of aquatic foods harvested from the near field region where the Upper Hookton aquifer discharges into the bay. The modeled doses using RESRAD-OFFSITE were 0.24 mrem/year from the fish pathway, with a worst-case sum of the peak dose of 0.4 mrem/year. The worst case sum of the peaks concentration for the groundwater discharging into the bay was 1.17 times the 1992 10 CFR 20, Appendix B, Table 2, Liquid Effluent MPCs. These calculations were very conservative and assumed 100% of the source term in the fuel pool was liberated to the aquifer within 40 days of the breach. It also assumed very low distribution coefficient (Kd values) for the radionuclides released, even though over 90% of the source term released was from insoluble sludge at the bottom of the fuel pool. A conservative surface water volume of 3.33E+5 cubic meters was used even though the Bay is on the order of 7E+8 cubic meters in volume. The lowest daily volume exchange from tidal action 23% for the three bay areas was used to calculate the surface water mean residence time. The more conservative annual aquatic food consumption vales from Regulatory Guide 1.109 were also applied to the calculation. In addition, although the nearest domestic well is located 0.58 miles upgradient from the fuel pool, the potential dose from drinking water and domestic water use at this distance was evaluated. This assumed the well was located 0.58 miles or 934.5 meters downgradient from the Contaminated Zone created by the release. The peak calculated annual dose occurred 1000 years post breach and resulted in 0.85 mrem/year assuming the well was the only
TSD # 09-020 Revision 00 Page 53 of 73 source of drinking water and water for domestic use. Based upon the results of this evaluation there are no significant off-site dose consequences of a heavy load drop for the spent fuel pool under current conditions and the consequence of the accident are bounded by the Liquid Tank release accidents evaluated in the Decommissioning FSAR. 6.0 Attachments 6.1 Attachment A - Map of ISFSI and Unit 3 Site Area Showing Geological Borings and Monitoring Wells 6.2 Attachment B - Buhne Point Geological Strata and Aquifers 6.3 Attachment C - Upper Hookton Groundwater Contours at MLLW 6.4 Attachment D - RESRAD-OFFSITE Input parameters 7.0 References 7.1 NRC Regulatory Guide 1.109, Calculation of Annual Doses To Man From Routine Releases of
-Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I.
7.2 NRC Regulatory Guide 1.179, Standard Format and Content of License Termination Plans for Nuclear Power Reactors, January.1999 7.3 NRC Regulatory Guide 1.184, Decommissioning of Nuclear Power Reactors, July 2000 7.4 NRC Regulatory Guide 1.185, "Standard Format and Content for Post-shutdown Decommissioning Activities Report, July 2000 7.5 NRC Regulatory Guide 1.186, Guidance and Examples for Identifying 10 CFR 50.2 Design Bases, December 2000 7.6 NRC Regulatory Guide 1.187, Guidance for Implementation of 10 CFR 50.59, Changes, Tests, And Experiments, November 2000 7.7 NUREG-0586, Final Generic Environmental Impact Statement (GELS) on Decommissioning of Nuclear Facilities, August 1988 7.8 NUREG-0586, Volume 1, Supplement 1, Final Generic Environmental Impact Statement (GELS) on Decommissioning of Nuclear Facilities, November 2002. 7.9 NUREG-1496, Generic Environmental Impact Statement in Support of Rulemaking on Radiological Criteria for License Termination of NRC Licensed Nuclear Facilities, Volume 1,, July 1997 7.10 NUREG-1738, Technical Study of Spent Fuel Pool Accident Risk at Decommissioning Nuclear Power Plants, October 2000 7.11 Nuclear Energy Institute 96-07 Guidelines for 10 CFR 50.59 Evaluations Final Draft -February 22, 2000 7.12 PG&E 652969, Humboldt Bay Power Plant, Unit No. 3, Plant Data, Bechtel Corporation Power Industrial Division, 1963
TSD # 09-020 Revision 00 Page 54 of 73 7.13 Swedish Nuclear Power Inspectorate (SKI) Report 00:5, On the interaction between fuel crud and water chemistry in nuclear power plants, Part I A Literature Survey, by Jiaxin Chen, Studsvik Material AB, SE-611 82 Nykoping Sweden, January 2000 7.14 PNNL-16018, Transportability Class of Americium in K Basin Sludge under Ambient and Hydrothermal Processing Conditions, C. H. Delegard, B. E. Schmitt, A. J. Schmidt, Prepared for the U.S. Department of Energy under Contract DE-AC05-76RL01830 Pacific Northwest National Laboratory Richland, Washington 99352, August 2006 7.15 IAEA-TECDOC-1012, Durability of Spent Nuclear Fuels and Facility Components in Wet Storage, IAEA, VIENNA, April 1998 7.16 Assessing the Origin and Fate of Cr, Ni, Cu, Zn, Pb, and V in an Industrial Polluted Soil by Combined Microspectroscopic Techniques and Bulk Extraction Methods, R. Terzano et a[., Environ. Sci. Technol., 41, 6762-6769. 7.17 PG&E, Final Hazards Summary Report, Humboldt Bay Power Plant Unit Number 3, Bechtel Corporation Power Industrial Division, 10/10/1962 7.18 NRC Humboldt Bay Power Plant, Unit No. 3, Decommissioning, Safety Evaluation Report, Docket No. 50-133, April 29, 1987. 7.19 Humboldt Bay Independent Spent Fuel Storage Installation, Pacific Gas and Electric Company, Final Safety Analysis Report Update, Revision 1 November 2007, PG&E Letter HIL-07-002, NRC Docket No. 72-27. 7.20 Data Collection Handbook To Support Modeling Impacts Of Radioactive Material In Soil, by C. Yu, C. Loureiro*, J.-J. Cheng, L.G. Jones, Y.Y. Wang, Y.P. Chia,* and E. Faillace Environmental Assessment and Information Sciences Division Argonne National Laboratory, Argonne, Illinois April, 1993 7.21 NUREG/CR-6937, DOE/HS-0005 User's manual for RESRAD Offsite Version 2, Argonne National Laboratory, C. Yu, et al., June 2007. 7.22 ANL/EAD-4, User's Manual for RESRAD Version 6, Environmental Assessment Division Argonne National Laboratory, by C. Yu, A.J. Zielen, J.-J. Cheng, D.J. LePoire, E. Gnanapragasam, S. Kamboj, J. Arnish, A. Wallo III,* W.A. Williams,* and H. Peterson*, July 2001 7.23 EPA 402-R-99-004A, Understanding Variation In Partition Coefficient, Kd, Values; Volume I: The Kd Model, Methods of Measurement, and Application of Chemical Reaction Codes, United States Environmental Protection Agency, August 1999. 7.24 EPA 402-R-99-004B, Understanding Variation In Partition Coefficient, Kd, Values; Volume II: Review of Geochemistry and Available Kd Values for Cadmium, Cesium, Chromium, Lead, Plutonium, Radon, Strontium, Thorium, Tritium (3H), and Uranium, United States Environmental Protection Agency, August 1999. 7.25 EPA 402-R-04-002C, Understanding Variation In Partition Coefficient, Kd, Values; Volume II: Review of Geochemistry and Available Kd Values for Americium, Arsenic, Curium, Iodine, Neptunium, Radium, and Technetium, July 2004 7.26 Environmental Report for the Decommissioning of Humboldt Bay Power Plant Unit No. 3, Prepared by Beverly S. Ausmus, et al, Bechtel Advanced Technology Division, k
TSD # 09-020 Revision 00 Page 55 of 73 Decontaminations and Restoration Office, Attachment 6 to PG&E Application for License Amendment DPR-7, July 1984. 7.27 United States Department of Agriculture, Natural Resources Conservation Service (NRCS), Soil Quality, Glossary of Terms web page. http:/Isoils.usda.gov/sqi/concepts/glossary.html 7.28 ACS Industries, Inc. Material Density Chart, Loose Materials http://www.acs-coupler.com/productslpdf/material%20density%20chart.pdf 7.29 RSCS Technical Support Document (TSD) 08-041, Evaluation of the Radiological Impact of No Circulating Water Flow in the Humboldt Bay Discharge Canal, April 2009. 7.30 Regulatory Guide 4.21 (Draft was issued as DG-4012) Minimization of Contamination and Radioactive Waste Generation: Life-Cycle Planning, June 2008 7.31 10 CFR Part 20, Standards for Protection Against Radiation, Section 20.1406, Minimization of Contamination, U.S. Nuclear Regulatory Commission, Washington, DC.
ATTACHMENT A TSD # 09-020 Revision 00 Page 56 of 73
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ATTACHMENT B TSD # 09-020 Revision 00 Buhne Point Geologic Strata and Aquifers Page 57 of 73 I TMr I. BUHN~1r- I.- I
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ATTACHMENT C TSD # 09-020 Upper Hookton Groundwater Contours at MLLW Revision 00 Page 58 of 73
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aER5,S-. Well and number ....- 2.- F.GURE 2.5-9I 4,76 476 Elevation El.et"n-flezomt'lcsu*-ra..,inRet",M of!plezomet'ic surface In feet MILLW W-.--M' .. '~~~>.....
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ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 59 of 73 Menu I Parameter Value Default Comment References Change Title ,, Title Humboldt Heavy Load SFP N Location Dose Slope and Transfer factor C:\PROGRAM FILES\RESRAD-Database FAMILY\OFFSITE\DCF N Slope Factor (Risk) Library FGR 13 Morbidity Y .............. Dose Conversion Factor Library FGR 11 Y ........ ........ Transfer Factor Library RESRAD Default Transfer Factors Y Cut Off Half Life (days) 3 N Total Available Nuclides 209 Y Total Number DCF or SF Nuclides 8 Y Intermediate Time Points - Number of Time Points 512 N Reduce calculation time Linear or Log Spacing Linear Y Update Progress of Computation Message Every (Seconds) 2 N Defaultis 0.0 seconds, to run faster Use Line Draw Character Checked Y Set Pathways External Gamma OFF N Release is 36 feet below grade Inhalation OFF N Release is 36 feet below grade Plant Ingestion OFF N Release is 36 feet below grade Meat Ingestion OFF N Release is 36 feet below grade Milk Ingestion OFF N Release is 36 feet below grade Aquatic Foods ON Y Pathway fish and invertebrates in bay Pathway upgradient on-site potable water wells. RESRAD will not calculate upgradient concentrations..Turn on for well Drinking Water OFF N concentrations of groundwater entering bay.
....... Soil Ingestion OFF N Release is 36 feet below grade Radon OFF Y Release is 36 feet below grade.
Modify Data - Preliminary Inputs
....... Activity pCi Y Dose mrem Y Basic Radiation Dose Limit (mrem) 25 N Same as decommissioning guideline Exposure Duration (years) 30 Y Number of Unsaturated Zones 1 Y
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 60 of 73 Modify Data - Site Layout Bearing of X Axis (clockwise angle from
-___north) 90 degrees Y X dimension of Primary Contamination in Emulates fuel pool volume for 19.3 feet meters 8.84 N deep. See Section 4.8 Y dimension of Primary Contamination in
_meters 7.48 N X Coordinate Smaller-98.53 Larger 101.5 Y coordinate Smaller Surface Water Body 128 Larger 178 N Modify Data - Physical and Hydrological ..... Site-Properties 38.7 inches per year 100 year average Precipitation (meters/year) 9.83E-01 N Eureka Ref 7.19 http://www.met.utah
.edu/jhoreVhtml/wx/
climate/windavg.ht Wind Speed meters/sec 3.04 N 3.04 m/s ml Contaminated Zone and Cover Length of Contaminated Zone Parallel to Emulates fuel pool volume for 19.3 feet aquifer flow (meters) 8.84 N deep. No mixing modeling immediate release Depth of Soil Mixing (meters) 0 N to saturated zone aquifer No dust deposition since injection of Deposition Velocity of dust (meters/sec) 0 N nuclides is subsurface Irrigation applied per year (meters/year) 0 N No irrigation of contaminated zone No evaporation or transpiration since Saturated Zone is below root depth and Evapotranspiration Coefficient 0 N covered with alluvial clay. This is the fraction of precipitation that does not penetrate the topsoil but leaves the area of concern as surface runoff; no loss is assumed for irrigation water. Zero was chosen to increase the Run Off Coefficient 0 N leach rate to groundwater. Rainfall and Runoff Index: This is a measure of the energy of the rainfall. It is used to compute the erosion rate. No erosion due to subsurface injection of Rainfall and Run Off 0 N contamination into saturated zone.
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 61 of 73 Slope-Length-Steepness Factor: This factor accounts for the profile of the terrain on the erosion rate. No erosion due to subsurface injection of Slope-Length-Steepness Factor 0 N contamination into saturated zone. Ref 7.21 Table 2.6-Cover and management factor 0.003 Y Grass no cover 95% of year 2 Support Practice Factor I Y To increase percolation out of contaminated Thickness Cover Material (meters) 0 N zone This is the 19.3 feet of cover above the Thickness- Contaminated Zone (meters) 5.88 N Hookton reservoir Total Porosity Contaminated Zone 0.9 N Top maximize water percolation to aquifer Erosion Rate Contaminated Zone (meters/year) 0 N Calculated by RESRAD for comparison to SPF Water Bulk Density Contaminated Zone (g/cm3) I N Concentrations To minimize input to surface water from Soil Erodability Factor Contaminated Zone erosion since the source term is injected at (tons/acre) 0 N depth It is the volumetric moisture content of soil at which (free) gravity drainage ceases. This is the amount of moisture that will be retained in a column of soil against the force of gravity. The field capacity is one of several hydrogeological parameters used to calculate water transport through the unsaturated part of the soil. Range from 1E-Field capacity contaminated zone 1.00E-05 N 5 to 1 an empirical and dimensionless parameter that is used to evaluate the saturation ratio (or the volumetric water saturation) of the soil according to a soil characteristic function called the conductivity function. Soil b parameter of contaminated zone 0.01 N Default is 5.3 range from 0-15 measure of the soil's ability to transmit water when subjected to a hydraulic gradient. The hydraulic conductivity depends on the soil grain size, the structure of the soil matrix, Hydraulic conductivity of contaminated the type of soil fluid, and the relative amount zone (meters/year) 1.00E+09 N of soil fluid (saturation) present in the soil
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 62 of 73 matrix. Default 10 Range 1E-3 to 1E+10. represents the fraction of the total volume of porous medium that is occupied by the water. The value should be less than the total porosity of the medium. Default 0.05. Volumetric water content 0.05 Y Range 0 - 1 Modify Data - Groundwater Transport Distancein direction parallelto aquiferflow from edge of contaminatedZone down gradient To determine groundwater well (meters) 119.500 N concentrations entering the bay. 420 feet from spent fuel pool as in previous calculations, contaminated zone is 7.48 meters wide on Y axis. Ref 7.18 Ref 7.17 surface water.(meters) 120.5 N 128.6-7.48 pg 149 Distance in the DirectionPerpendicularto
........... Aquifer Flow Distance in the Direction Perpendicular to AquiferFlow from Contamination to Well: This the distance, in meters (m),
between two groundwater flow lines, one through the center of the contamination and the other thorough the well. It is used in the computation of dilution due to dispersion in the saturated zone, and it applies to water well (meters) 0 N extracted from a well. distance, in meters (m), between two groundwater flow lines, one through the center of the contamination and the other through the near edge of the surface water body. It is used to compute the contamination flux from the Right Edge of Surface Water Body groundwater into the surface water (meters) -98.53 N body.
. ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 63 of 73 Left Edge ofSurface Water Body (meters) 101.5 N This is the fractional accuracy desired in the Romberg integration used to calculate the contaminant flux or concentration in groundwater. A lower value will likely require the use of a larger number of points in this numerical integration technique and thus a longer computation time. For each Romberg refinement or cycle number, the number of integrand function evaluations is 2N, where N is the cycle number. Thus, if the convergence criterion is set too low, the computation time becomes excessive, and convergence may not be achieved. Default Convergence Criterion: 0.01 N is 0.001 ..........
Main Sub Zones in Saturated Zone I Y Main Sub Zones in Each Partially Saturated Zone I Y Modify Data - Unsaturated Zone Properties This creates a very thin unsaturated zone placing the contaminated zone Unsaturated Zone Thickness (meters) 0.01 N directly on the top of the aquifer. Set the density to the same as the fuel pool water to allow direct input of water 3 Dry Bulk Density (g/crnm ) 1 N concentration values A high value is used to maximize flow Effective porosity 0.99 N through the zone Field capacity 1.00E-05 N See contaminated zone description Note message in field says upper bound is Hydraulic conductivity (meters/year) 1.OOE+06 N 1 E6 Provides rapid radionuclide removal through Soil b parameter of contaminated zone 0.01 N zone. This is the ratio between the longitudinal dispersion coefficient and pore water velocity. It has the dimension of length. This parameter depends on the thickness of the zone and ranges from one one-hundredth of Longitudinal Dispersivity 0.01 N the thickness to the order of the thickness. Modify Data - Saturated Zone Properties Meters thick Upper Hookton Aquifer see Dwg 55428, Ref Saturated Zone Thickness (meters) 9.52 N Rad Data Sheet 7.19
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 64 of 73 Total Porosity of Saturated Zone 0.4 N Same as previous calculation Ref 7.19 Effective Porosity of Saturated Zone 0.25 N Same as previous calculation Ref 7.19 Same as previous calculation. Based on down-hole flow meter measurements in the upper Hookton aquifer in the Unit 3 area (Reference 2) for wells MW-1 through MW-1 I and calculated permeability using the tidal method, a flow velocity range of 3,100 to 10,400 Hydraulic Conductivity of Saturated Zone ft/yr (3x10" to 3x1 0-2 cm/sec) was (meters/year) 3169.92 N calculated. This equals 10,400 near. Ref 7.19 Hydraulic Gradient of Saturated Zone: This is the slope of the surface of the water table. Ref 15 Little vertical flow occurs within the upper Hookton aquifer. Vertical gradients range from 10 to 20 ft/mile (0.002 to 0.004 Hydraulic gradient to well of saturated zone 0.003 N ftift) . Ref 7.19 Hydraulic gradient to surface water body of Places it in highest concentrations saturated zone 0.003 N calculated in model Depth of Aquifer contributing to well Places it in highest concentrations (meters below water table) 14 N calculated in model Depth of Aquifer contributing to surface water (meters below water table) 14 N Same as Previous Calculation This is the ratio between the longitudinal dispersion coefficient and pore water velocity. It has the dimension of length. This parameter depends on the thickness of the zone and ranges from Longitudinal dispersivity of saturated zone one one-hundredth of the thickness to for well in meters 0.3048 N the order of the thickness. Ref 7.18 Ref 7.17 Longitudinal dispersivity of saturated zone for surface water in meters 0.3048 N Ref 7.18 Ref 7.17 Same as Previous Calculation This is the ratio between the horizontal lateral Horizontal dispersivity of saturated zone for dispersion coefficient and pore water well in meters 0.1524 N velocity. It has the dimension of length. Ref 7.18 Ref 7.17 Horizontal dispersivity of saturated zone for surface water in meters 0.1524 N Same as Previous Calculation Ref 7.18 Ref 7.17
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 65 of 73 Dispersion is considered to be inactive in the vertical direction, if the concentration profile in the vertical direction becomes essentially uniform because of'repeated reflection of the plume by the lower impermeable layer and the water table. It is also inactive if a zero value is specified for the vertical-lateral dispersivity. This is likely due to upper strata Vertical lateral dispersivity of saturated clay and aquitard below as well as tidal zone for well in meters Do not disperse vertically N influence. Ref 7.21 Vertical lateral dispersivity of saturated zone for surface water in meters Do not disperse vertically N No irrigation in area and not likely to make it Irrigation applied per year (meters/year) through upper strata to brackish water well 0 N aquifer of Upper Hookton Irrigation applied per year (meters/year) surface water body 0 N Assumes no removal of water through dispersion to atmosphere since release is Evapotranspiration coefficient 0 N subsurface under clay deposits. Evapotranspiration coefficient 0 N Runoff coefficient 0 N Runoff coefficient 0 N Modify Data - Water Use Consumption by humans (liters/year) 730 IN Reg Guide 1.109 Table E-5 Adult Use indoors of dwelling (liters/day) 225 Y Consumption by humans fraction from Well I Y Use indoors of dwelling fraction from Well I Y Number of individuals I Y Well pumping rate (cubic meters per year) 5100 Y Modify Data - Surface Water Body Sediment delivery ratio I Y ......... Volume of surface water body (cubic meters) 3.33E+05 N Same Near Field as TSD (Ref 7.29) Ref 7.29, 7.26 Mean residence time of water in surface Ref 7.29, 7.26, as water body (years) 8.40E-02 N 23% for Entrance Bay defined Ref 7.21 Modify Data - Ingestion Rates Drinking Water (liters/year) 730 N Reg Guide 1.109 Table E-5 Adult Ref 7.1 Fish (kg/yr) 21 N Reg Guide 1.109 Table E-5 Adult Ref 7.1
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 66 of 73 Reg Guide 1.109 Table E-5 Adult Other Crustacea and mollusks (kglyr) 5 N Seafood Ref 7.1 Assume 100% from contaminated zone Drinking Water fraction from affected area 1 N as in RG 1.109 Assume 100% from contaminated zone Fish fraction from affected area 1 N as in RG 1.109 Crustacea and mollusks fraction from Assume 100% from contaminated zone affected area 1 N as in RG 1.109 Modify Data - Inhalation, Gamma None Modify Data - Radon None Modify Data - Soil Concentrations - Ac-227, Np-237, Pa-231, Pb-21 0, Po-210, Ra-226, Ra-228, Th-228, Th-229, Th-230, Th-232 RESRAD calculated value a daughter Contaminated Zone (pCi/l) 7.OOE+00 N radionuclide The fraction of the available radionuclide leached out from the contaminated zone per unit of time. Accepted values range from 0 to 1E+34. If the user does not input a leach rate, RESRAD-OFFSITE will estimate a leach rate by equating the initial release rate to the equilibrium desorption release rate, computed using the user-specified distribution coefficient. Default is used since Kds are specified for each nuclide so leach rate has no impact on calculation. of the radionuclide inthe region of primary I Release and Air Transport - Leach Rate 0.00E+00 Y contamination. Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Saturated Zone (cm/`g) 20 N Not a dose significant nuclide low Kd used. Sediment in surface water body 1000 Y Fruit, grain, non-leafy fields 1000 Y Leafy Vegetable Fields 1000 Y Livestock feed grain fields 1000 Y Dwelling Site 1000 Y Modify Data - Soil Concentrations - Am-241 Contaminated Zone (pCi/g) 7.50E+02 N Calculated overall fuel pool concentration
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 67 of 73 See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.00E+00 Y RESRAD based on Kd To ensure rapid release to aquifer. RESRAD has run time error when 0 values are used Distribution Coefficient Contaminated Zone for elements other than carbon and (cm 3/g) 0.001 N hydrogen. 3 Unsaturated Zone (cm /g) 0.001 N To ensure rapid release to aquifer Based upon evaluation of americium Kds for course sand in EPA (Ref 7.25) and choice of conservative, low Kd as discussed in Technical Support Document for the Ref 7.25, Section ...... Saturated Zone (cm3/g) 20 N calculation. 4.10.1 Sediment in surface water body 1000 Y Fruit, grain, non-leafy fields 1000 Y
...... .. Leafy Vegetable Fields 1000 Y
...... .. Livestock feed grain fields 1000 Y Dwelling Site 1000 Y Modify Data - Soil Concentrations - Am-243 RESRAD Calculated Value a daughter Contaminated Zone (pCi/g) 0.OOE+00 N radionuclide See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.00E+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Based upon evaluation of americium Kds for course sand in EPA (Ref 7.25) and choice of conservative, low Kd as discussed in Technical Support Document for the Ref 7.25, Section Saturated Zone (cm3 /g) 20 N calculation. 4.10.1 Sediment in surface water body 1000 Y Fruit grain, non-leafy fields 1000 Y ......
Leafy Vegetable Fields 1000 Y Livestock feed grain fields 1000 Y Dwelling Site 1000 Y Modify Data - Soil Concentrations - C-14 .... Contaminated Zone (pCi/g) 7.16E+00 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport- Leach Rate 0.00E+00 Y RESRAD based on Kd
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 68 of 73 Default Kd that assumes carbon is moving with water with no sorption or other soil interactions as in dissolved CO2. This is a Distribution Coefficient Contaminated Zone very conservative assumption since it is (cm 3Ig) 0 Y likely in the oxides in the sludge. Unsaturated Zone (cm3 /g) 0 Y Saturated Zone (cm3/g) 0 Y S,_,ediment in surface water body 0 Y .... Fruit, grain; non-leafy fields 0 Y Leafy Vegetable Fields 0 Y ...... Livestock feed grain fields 0 Y Dwelling Site 0 Y. Modify Data - Soil Concentrations - Cm-243, Cm-244 One half the calculated Cm-243/244 Contaminated Zone (p.Cig) 1.50E+02 N concentration in the fuel pool water. See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.00E+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer* 3 Unsaturated Zone (cm /g) 0.001 . N To ensure rapid release to aquifer Based upon evaluation of Curium Kds for course sand in EPA (Ref 7.25) and choice of conservative, low Kd as discussed in Technical Support Document for the Ref 7.25, Section Saturated Zone (cm3 /g) 20 N calculation. 4.10.2 Sediment in surface water body 1000 Y Fruit, grain, non-leafy fields 1000 Y ..... Leafy Vegetable Fields 1000 Y Livestock feed grain fields 1000 Y I Dwelling Site 1000 Y -- Modify Data - Soil Concentrations - Co-60 .... Contaminated Zone (pCi/g) 5.22E+03 N Calculated overall fuel pool concentration ....... See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (crn3/g) 0.001 N To ensure rapid release to aquifer
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 69 of 73 Ref 7.18 Ref 7.17 Saturated Zone (cr3/g) N Same as previous calc Section 4,.4 Sediment in surface water body 1000 Y Fruit, grain, non-leafy fields 1000 Y Leafy Vegetable Fields 1000 Y Uvestock feed grain fields 1000 Y Dwelling Site 1000 Y Modify Data - Soil Concentrations -,Cs-I37 ......... .......................... Contaminated Zone (pCi/g) 1.22E+03 N Calculated overall fuel pool concentration ....... See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm 3/q) 0.001 N To ensure rapid release to aquifer Ref 7.18 Ref 7.17 Saturated Zone (crn3/g) 20 N Same as previous calc Section 4.4 Sediment in surface water body 4600 Y
.......Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y.
Livestock feed grain fields 4600 Y .......... Dwelling Site 4600 Y Modify Data - Soil Concentrations - Eu- 54 . -" Contaminated Zone (pCi/g) 3.13E+01 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate .00HE+00 Y RESRAD based on Kd *_ .... Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer .... 3
._Unsaturated Zone (cm /g) 0.001 N To ensure rapid release to aquifer Saturated Zone (cm3/g) 20 N Not a dose significant nuclide low Kd used. ....
.......... Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y
....... Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y Dwelling Site 4600 Y ._..
Modify Data - Soil Concentrations - Fe-55 ... ............ Contaminated Zone (pCi!g) 1.09E+03 N Calculated overall fuel pool concentration _
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 70 of 73 See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer 3 Unsaturated Zone (cm /g) 0.001 N To ensure rapid release to aquifer ................. Saturated Zone (cm3lq) 20 N Not a dose significant nuclide low Kd used. Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y
........ Dwelling Site 4600 Y Modify Data - Soil Concentrations - H-3 Contaminated Zone (pCiig) 3.03E+01 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (crn 3/g) 0 N To ensure rapid release to aquifer Unsaturated Zone (crn 3/g) 0 N To ensure rapid release to aquifer Default Kd that assumes tritium is moving Saturated Zone (cm 1g) 0 Y with water.
Sediment in surface water body 0 Y Fruit, grain, non-leafy fields 0 Y Leafy Vegetable Fields 0 Y Livestock feed grain fields 0 Y Dwelling Site 0 Y MOdify Data - Soil Concentrations - Ni-59 ,,__ Contaminated Zone (pCi/) 6.99E+01 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd ..... Distribution Coefficient Contaminated Zone (cm3 /g) 0.001 N To ensure rapid release to aquifer Unsaturated.Zone (cmn3/g) 0.001 N To ensure rapid release to aquifer Saturated Zone (cmr3/g) 20 N Not a dose significant nuclide low Kd used. Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 71 of 73
*- Livestock feed grain fields 4600 Y Dwelling Site 4600 Y.
Modify Data - Soil Concentrations - Ni-63 Contaminated Zone (pCi/g) 1.08E+04 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd ..... Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer .... Unsaturated Zone (cmr/g) 0.001 N To ensure rapid release to aquifer Saturated Zone (cm.3/g) 20 N Not a dose significant nuclide low Kdused. Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y .. ............... Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y Dwelling Site 4600 Y Modify Data - Soil Concentrations - Pu-238 ............. ,__......... Contaminated Zone (pCi/g) 2.30E+02 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd ,,, Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Based upon evaluation of Plutonium Kds for course sand in EPA (Ref 7.25) and choice of conservative, low Kd as discussed in Technical Support Document for the, Ref 7.25, Section Saturated Zone (cm3/g) 10 N calculation. 4.10.3 Sediment in surface water body 4600 Y Fruit, Rrain, non-leafy fields 4600 Y .... Leafy Vegetable Fields 4600 Y ivestock feed grain fields 4600 Y Dwelling Site 4600 Y .... Modify Data - Soil Concentrations - Pu-239, Pu-240 One half the calculated Pu-239/240 Contaminated Zone (pCi/g) 1.32E+02 N concentration in the fuel pool water. See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 72 of 73 Distribution Coefficient Contaminated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Based upon evaluation of Plutonium Kds for course sand in EPA (Ref 7.25) and choice of conservative, low Kd as discussed in Technical Support Document for the Ref 7.25, Section
.... _Saturated Zone (cm3/g) 10 N calculation. 4.10.3 Sediment in surface water body 4600 Y..................
Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y Dwelling Site 4600 Y Modify Data - Soil Concentrations - Pu-241 Contaminated Zone (pCi/g) 4.13E+03 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm 3/g) 0.001. N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Based upon evaluation of Plutonium Kds for course sand in EPA (Ref 7.25) and choice of conservative, low Kd as discussed in 3 Technical Support Document for the Ref 7.25, Section Saturated Zone (cm 3/g) 10 N calculation. 4.10.3 Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y
*_Dwelling Site 4600 Y Modify Data - Soil Concentrations - Sr-90 Contaminated Zone (pCi/g) 2.74E+02 N Calculated overall fuel pool concentration See Ac-227 explanation calculated by Release and Air Transport - Leach Rate 0.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (cm 3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3 /g) 0.001 N To ensure rapid release to aquifer
ATTACHMENT D TSD # 09-020 RESRAD-OFFSITE Input Parameters Revision 00 Page 73 of 73 Ref 7.18 Ref 7.17, Saturated Zone (cm3/g) 0.4 N Same as previous calc Section 4.4 Sediment in surface water body 30 Y Fruit, grain, non-leafy fields 30 Y Leafy' Vegetable Fields _30 Y Livestock feed grain fields 30 Y Dwelling Site 30 Y Modify Data - Soil Concentrations - U-233, U-234 One half the calculated U-233/234 Contaminated Zone (pCi/l) 2.34E-01 N concentration in the fuel pool water. See Ac-227 explanation calculated by Release and Air Transport - Leach Rate O.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (crn 3/g) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Saturated Zone (cm3/g) 20 N Not a dose significant nuclide low Kd used. Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y Dwelling Site 4600. Y Modify Data - Soil Concentrations - U-235, U-236 ................ One half the calculated U-235/236 Contaminated Zone (pCi/g) 6.43E-02 N concentration in the fuel pool water. See Ac-227 explanation calculated by Release and Air Transport - Leach Rate O.OOE+00 Y RESRAD based on Kd Distribution Coefficient Contaminated Zone (CM3/q) 0.001 N To ensure rapid release to aquifer Unsaturated Zone (cm3/g) 0.001 N To ensure rapid release to aquifer Saturated Zone (cm3/g) 20 N Not a dose significant nuclide low Kd used.
-Sediment in surface water body 4600 Y Fruit, grain, non-leafy fields 4600 Y Leafy Vegetable Fields 4600 Y Livestock feed grain fields 4600 Y Dwelling Site 4600 Y}}