ML17208A125
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN CHAPTER 4, REVISION 1 REMEDIATION PLAN
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 TABLE OF CONTENTS
- 4. SITE REMEDIATION PLAN ............................................................................................. 4-1 4.1. Remediation Actions and ALARA Evaluations .............................................. 4-1 4.2. Remediation Actions ....................................................................................... 4-2 4.2.1. Structures ......................................................................................................... 4-2 4.2.1.1. Scabbling and Shaving..................................................................................... 4-3 4.2.1.2. Needle Guns ..................................................................................................... 4-3 4.2.1.3. Chipping........................................................................................................... 4-4 4.2.1.4. Sponge and Abrasive Blasting ......................................................................... 4-4 4.2.1.5. Pressure Washing ............................................................................................. 4-4 4.2.1.6. Washing and Wiping........................................................................................ 4-4 4.2.1.7. High-Pressure Water Blasting.......................................................................... 4-5 4.2.1.8. Grit Blasting ..................................................................................................... 4-5 4.2.1.9. Removal of Activated/Contaminated Concrete ............................................... 4-5 4.2.1.10. Additional Remedial Actions ........................................................................... 4-6 4.2.2. Soil................................................................................................................... 4-6 4.3. Remediation Activities Impact on the Radiation Protection Program ............ 4-6 4.4. ALARA Evaluation ......................................................................................... 4-8 4.4.1. ALARA Analysis of Soil Remediation ........................................................... 4-9 4.4.1.1. Calculation of Benefits .................................................................................... 4-9 4.4.1.2. ALARA Analysis Parameters ........................................................................ 4-10 4.4.1.3. Calculation of Costs ....................................................................................... 4-10 4.4.1.4. Calculation of Total Cost for Soil Remediation by Excavation and Disposal .................................................................................................. 4-11 4.4.1.5. Residual Radioactivity in Soils that are ALARA .......................................... 4-12 4.4.2. ALARA Analysis for Remediation of Basement Structures ......................... 4-13 4.4.2.1. ALARA Analysis Equation for Remediation of Basement Structures .......... 4-15 4.4.2.2. Remedial Action Costs .................................................................................. 4-16 4.4.2.3. Transport and Disposal of the Waste (CostWD) .............................................. 4-18 4.4.2.4. Non-Radiological Risks (CostACC) ................................................................. 4-18 4.4.2.5. Transportation Risks (CostTF) ........................................................................ 4-19 4.4.2.6. Worker Dose Estimates (CostWDose) ............................................................... 4-19 4.4.2.7. Monetary Cost of Dose to the Public (CostPDose) ........................................... 4-19 4.4.2.8. Total Cost (CostT) .......................................................................................... 4-20 4.4.2.9. Residual Radioactivity in Basement Structures that are ALARA ................. 4-20 4.4.2.10. Conclusion ..................................................................................................... 4-23 4.5. References ..................................................................................................... 4-25 4-i
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 LIST OF TABLES Table 4-1 Basement DCGLBS for the Auxiliary Building ............................................. 4-21 Table 4-2 Radionuclide Half-Life(s), Decay Constant(s) and Mixture ......................... 4-23 Table 4-3 Dose for Individual Scenarios (DOSEAMCG) ................................................. 4-23 Table 4-4 ALARA Analysis for Volumetrically Contaminated Subsurface Structures - Auxiliary Building 542 ft. ......................................................... 4-24 4-ii
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 1 LIST OF ACRONYMS AND ABBREVIATIONS 2 AF Area Factor 3 ALARA As Low As Reasonably Achievable 4 AMCG Average Member of the Critical Group 5 BFM Basement Fill Model 6 CFR Code of Federal Regulations 7 CVS Contamination Verification Survey 8 DCGL Derived Concentration Guideline Levels 9 DSAR Defueled Safety Analysis Report 10 EMC Elevated Measurement Comparison 11 FSS Final Status Survey 12 HEPA High Efficiency Particulate Air 13 ISOCS In Situ Object Counting System 14 LLRW Low Level Radioactive Waste 15 LSA Limited Specific Activity 16 LTP License Termination Plan 17 MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual 18 NRC Nuclear Regulatory Commission 19 ODCM Off Site Dose Calculation Manual 20 ROC Radionuclides of Concern 21 RPT Radiation Protection Technician 22 SAFSTOR SAFeSTORage 23 SFP Spent Fuel Pool 24 TEDE Total Effective Dose Equivalent 25 WWTF Waste Water Treatment Facility 26 ZNPS Zion Nuclear Power Station 27 ZSRP Zion Station Restoration Project 4-i
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 28 29 Page Intentionally Left Blank 4-ii
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 30 4. SITE REMEDIATION PLAN 31 In accordance with 10 CFR 50.82(a)(9)(ii)(C), the License Termination Plan (LTP) must provide 32 the plans for site remediation. These plans must include the provisions to meet the criteria 33 from Subpart E of 10 CFR 20 before the site may be released for unrestricted use. The two 34 radiological criteria for unrestricted use specified in 10 CFR 20.1402 are: (1) the Total Effective 35 Dose Equivalent (TEDE) from residual radioactivity that is distinguishable from background 36 radiation must not be greater than 25 mrem/yr to the Average Member of the Critical Group 37 (AMCG) and (2) residual radioactivity levels must be As-Low-As-Reasonably-Achievable 38 (ALARA).
39 Decontamination and dismantlement activities will be conducted in accordance with established 40 Radiation Protection, Safety and Waste Management programs which include approved written 41 procedures. These programs and procedures are frequently audited for technical content and 42 compliance. Revisions have, and will continue to be made to these programs and procedures to 43 accommodate the changing work environment inherent to reactor decommissioning and, 44 documented, processed and approved in accordance with existing administrative procedures 45 using 10 CFR 50.59 and Regulatory Guide 1.187, Guidance for Implementation of 46 10 CFR 50.59 Changes, Tests and Experiments (Reference 4-1) as guidance. Consistent with 47 Regulatory Guide 1.179, Standard Format and Contents for License Termination Plans for 48 Nuclear Power Reactors (Reference 4-2), details regarding changes to the Radiation Protection 49 Program to address remediation and decommissioning activities are not provided in this LTP, but 50 periodic updates to the Zion Station Defueled Safety Analysis Report (DSAR) (Reference 4-3) 51 will provide such details.
52 This chapter describes the methods that may be used to remediate contaminated systems, 53 components and structures. The methods for demonstrating compliance with the ALARA 54 criterion in 10 CFR 20.1402 is also described. Note that Chapter 6 provides the methods for 55 demonstrating compliance with the 25 mrem/yr dose criterion. AlsoAlso, note that Chapter 3 56 describes in detail the remaining site remediation and dismantlement activities and the order in 57 which they will occur for each structure, system and/or component.
58 This chapter also provides a summary of the radiation protection methods and control procedures 59 that will be employed during site dismantlement and remediation.
60 4.1. Remediation Actions and ALARA Evaluations 61 When dismantlement and decontamination actions are completed, residual radioactivity may 62 remain on building surfaces and in site soils at concentrations that correspond to the maximum 63 annual dose criterion of 25 mrem/yr. The remaining residual radioactivity must also satisfy the 64 ALARA criterion, which requires an evaluation as to whether it is feasible to further reduce 65 residual radioactivity to levels below those necessary to meet the dose criterion (i.e., to levels 66 that are ALARA).
67 The ALARA evaluation calculates the concentration at which the averted collective radiation 68 dose, converted into dollars, is equal to the costs of continued remediation (e.g., risk of 69 transportation accidents converted into dollars, worker and public doses associated with the 70 remediation action converted into dollars, and the actual costs to perform the remediation 4-1
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 71 activity). If this concentration is below the concentrations that correspond to the maximum 72 annual dose criterion, then further reduction of residual radioactivity is justified by ALARA.
73 Regardless of the outcome of the quantified cost/benefit calculation provided in this chapter, the 74 final dose from residual radioactivity is expected to be well below the dose criterion. The 75 majority of the basement surfaces to be backfilled have minimal contamination. In addition, any 76 areas that are identified as potentially containing activity at levels that could exceeding the 77 Derived Concentration Guideline Level (DCGL), as measured during Final Status Survey (FSS) 78 by the In Situ Object Counting System (ISOCS), will be remediated. Industry standard 79 remediation methods have been shown to remove contamination to levels significantly below the 80 target levels, in this case the DCGL, and this result is expected for any remediation. The 81 combination of low contamination levels over the majority of the basement surfaces combined 82 with remediated areas likely containing activity well below the DCGL, ensures that the final 83 dose from residual radioactivity at license termination will be well below the 25 mrem/yr dose 84 criterion. Based on characterization results, there is limited contamination expected in soil, 85 buried pipe or end-state structures, or above grade buildings with a corresponding dose that is 86 also expected to be well below 25 mrem/yr.
87 4.2. Remediation Actions 88 Remediation actions are performed throughout the decommissioning process and the techniques, 89 methods and technologies are standard to the commercial nuclear industry. All of the 90 remediation actions described may not necessarily be required, but are listed as possible actions 91 that may be taken during the decommissioning of Zion Nuclear Power Station (ZNPS). The 92 appropriate remediation technique(s), method(s) and/or technologies that will be employed is 93 dependent on the physical composition and configuration of the contaminated media requiring 94 remediation. At ZNPS, the principal media that will be subjected to remediation are concrete 95 structural surfaces. Characterization survey results and historical survey data indicate that there 96 is minimal soil contamination and no groundwater contamination identified to date.
97 4.2.1. Structures 98 The general approach to structure remediation at Zion Station Restoration Project (ZSRP) is 99 driven by section 8.5 of Exhibit C, Lease Agreement, Removal of Improvements; Site 100 Restoration integral to the Zion Nuclear Power Station, Units 1 and 2 Asset Sale Agreement 101 (Reference 4-4) which requires the demolition and removal of all on-site buildings, structures, 102 and components to a depth of at least three feet below grade. Consequently, the only structures 103 that will remain at license termination are the concrete walls and floors below 588 foot elevation 104 in the Unit 1 Containment Building, Unit 2 Containment Building, Auxiliary Building, Turbine 105 Building, Fuel Handling Building, Crib House/Forebay, Waste Water Treatment Facility 106 (WWTF), Circulating Water Intake Piping and Circulating Water Discharge Tunnels. All 107 impacted systems, components and structures above the 588 foot elevation will be removed 108 during the decommissioning process and disposed of as a waste stream. The current 109 decommissioning approach for ZSRP also calls for the beneficial reuse of clean concrete from 110 building demolition as clean fill. The only concrete structures that will be considered are those 111 where the probability of the presence of residual contamination is minimal and surveys 112 demonstrate that the concrete is free of plant derived radionuclides and hazardous paint coatings.
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 113 The remaining structural surfaces that will remain at ZNPS following the termination of the 114 license are solid concrete structures which will be covered by at least three 3 feet of soil and 115 physically altered to a condition which would not allow the remaining structural surfaces, if 116 excavated, to be realistically occupied. Consequently, the only applicable dose pathway is from 117 the leaching of residual radioactivity concentrations in the concrete to groundwater. The dose 118 model that will be used to calculate and quantify the future dose to groundwater is referred to as 119 the Basement Fill Model (BFM).
120 Scan measurements, static measurements and/or the analysis of volumetric sample(s) of the 121 remaining concrete media will be used to calculate the remaining total concentration of residual 122 activity remaining in the subsurface concrete structures and the corresponding dose to 123 groundwater. The concrete walls and floors of the basements will be remediated to levels that 124 will provide high confidence that FSS measurements with ISOCS will not exceed radionuclide-125 specific DCGLs that represent the annual dose criterion for unrestricted use specified in 126 10 CFR 20.1402. Rather than using an adjusted gross Derived Concentration Guideline Level 127 (DCGL), the concrete walls and floors from the remaining subsurface basements will be 128 remediated to action levels commensurate with volumetric concentration limits that represent the 129 maximum annual dose criterion for unrestricted release specified in 10 CFR 20.1402.
130 Remediation techniques that may be used for the structural surfaces below 588 foot elevation 131 include washing, wiping, pressure washing, vacuuming, scabbling, chipping, and sponge or 132 abrasive blasting. Cost estimates for these techniques also include the amount of water 133 generated and the cost to process, package and ship this waste. Concrete removal may include 134 using machines with hydraulic-assisted, remote-operated, articulating tools. These machines 135 have the ability to exchange scabbling, shear, chisel and other tool heads.
136 4.2.1.1. Scabbling and Shaving 137 The principal remediation method expected to be used for removing contaminants from concrete 138 surfaces is scabbling and shaving. Scabbling entails the removal of concrete from a surface by 139 the high-velocity impact of a tool with the concrete surface which transforms the solid surface to 140 a volumetric particulate which can be removed. One method of scabbling is a surface removal 141 process that uses pneumatically operated air pistons with tungsten-carbide tips that fracture the 142 concrete surface to a nominal depth of 0.125 inches at a nominal rate of about 130 ft2 or 143 12.07 m2 per hour. The scabbling pistons (feet) are contained in a close-capture enclosure that is 144 connected by hoses to a sealed vacuum and collector system. Shaving uses a series of diamond 145 cutting wheels on a spindle, and performs at similar rates to scabbling. The wheels are also 146 contained in a close capture enclosure similar to scabbling equipment. The fractured media and 147 dusts from both methods are deposited into a sealed removable container. The exhaust air passes 148 through both roughing and absolute High Efficiency Particulate Air (HEPA) filtration devices.
149 Dust and debris generated through these remediation processes is collected and controlled during 150 the operation.
151 4.2.1.2. Needle Guns 152 A second method of scabbling is accomplished using needle guns. The needle gun is a 153 pneumatic air-operated tool containing a series of tungsten-carbide or hardened steel rods 154 enclosed in housing. The rods are connected to an air-driven piston to abrade and fracture the 4-3
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 155 media surface. The media removal depth is a function of the residence time of the rods over the 156 surface. Typically, one to two millimeters are removed per pass. Generated debris collection, 157 transport and dust control are accomplished in the same manner as other scabbling methods. Use 158 of needle guns for removal and chipping of media is usually reserved for areas not accessible to 159 normal scabbling operations. These include, but are not limited to, inside corners, cracks, joints 160 and crevices. Needle gunning techniques can also be applied to painted and oxidized surfaces.
161 4.2.1.3. Chipping 162 Chipping includes the use of pneumatically operated chisels and similar tools coupled to 163 vacuum-assisted collection devices. Chipping activities are usually reserved for cracks and 164 crevices. This action is also a form of scabbling.
165 4.2.1.4. Sponge and Abrasive Blasting 166 Sponge and abrasive blasting are similar techniques that use media or materials coated with 167 abrasive compounds such as silica sands, garnet, aluminum oxide, and walnut hulls. Sponge 168 blasting is less aggressive, incorporating a foam media that, upon impact and compression, 169 absorbs contaminants. The medium is collected by vacuum and the contaminants are washed 170 from the medium so the medium may be reused. Abrasive blasting is more aggressive than 171 sponge blasting but less aggressive than scabbling. Both operations use intermediate air 172 pressures. Sponge and abrasive blasting are intended for the removal of surface films and paints.
173 4.2.1.5. Pressure Washing 174 Pressure washing uses a nozzle of intermediate water pressure to direct a jet of pressurized water 175 that removes superficial materials from the suspect surface. A header may be used to minimize 176 over-spray. A wet vacuum system is used to suction the potentially contaminated water into 177 containers for filtration or processing.
178 4.2.1.6. Washing and Wiping 179 Washing and wiping decontamination techniques are actions that are typically performed during 180 the course of remediation activities for housekeeping and to minimize the spread of loose surface 181 contamination. ZSRP will implement good housekeeping throughout decommissioning to 182 ensure ALARA, to It is not anticipated that this remediation approach will be employed at ZSRP 183 to reduce the residual activity in structural surfaces for the purpose of meeting the 25 mrem/yr 184 dose criterion but rather, to comply with the open air demolition criteria in ZionSolutions 185 TSD 10-002, Technical Basis for Radiological Limits for Structure/Building Open Air 186 Demolition (Reference 4-5) and, to ensure that loose surface contamination is removed prior to 187 evaluating the surface for acceptable concentrations of residual activity.
188 Washing and wiping techniques are actions that are normally performed during the course of 189 remediation activities and will not always be evaluated as a separate ALARA action. When 190 washing and wiping techniques are used as the sole means to reduce residual contamination 191 below DCGL levels, ALARA evaluations will be performed. Washing and wiping techniques 192 used as housekeeping or good practice measures will not be evaluated.
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 193 4.2.1.7. High-Pressure Water Blasting 194 Most contaminated piping will be removed and disposed of as radioactive waste. Any pipe 195 systems or sections of pipe systems that reside below the 588 foot elevation that will be 196 abandoned in place will be inspected and surveyed as described in Chapter 5. If radiological 197 conditions inside the pipe are in excess of the release criteria, then in situ remediation will be 198 performed. One method that may be used to remediate the pipe interior surfaces is high pressure 199 water blasting. A High-Pressure Liquid-Jetting System has a high pressure water pump capable 200 of producing a water pressure of 10,000 psi to 20,000 psi at an actual flow rate that ranges from 201 44 gallons per minute at 10,000 psi to 23 gallons per minute at 20,000 psi. A rotating jet-mole 202 tip is used for 360 degree coverage of pipe interiors. The jet-mole is attached to a lance and 203 high-pressure hose. The lance is manually advanced through the interior of the pipe. As the 204 lance is advanced, the high-pressure water abrades the interior surface of the pipe, removing the 205 corrosive layer, internal debris and radiological contamination. The waste water containing the 206 removed contamination is then collected and stored for processing as liquid radiological waste.
207 4.2.1.8. Grit Blasting 208 Another approach that may be used to remediate the surfaces of pipe interior surfaces is grit 209 blasting. Grit blasting uses grit media such as garnet or sand under intermediate air pressure 210 directed through a nozzle that is pulled through the closed piping at a fixed rate. The grit 211 blasting action removes the interior surface layer of the piping. A HEPA vacuum system 212 maintains the sections being cleaned under negative pressure and collects the media for reuse or 213 disposal. The final system pass is performed with clean grit to remove any residual 214 contamination.
215 4.2.1.9. Removal of Activated/Contaminated Concrete 216 As previously stated, the principal means of remediating concrete surfaces is scabbling/shaving.
217 If the concrete structure is designated for complete removal, such as interior concrete walls or the 218 Bio-Shield, the primary method that will be used to completely remove the concrete is through 219 large scale demolition using hydraulic-operated crushing shears and jack-hammers fitted to large 220 tracked excavators. Concrete structures will be fractured and crushed by these tools. As the 221 concrete is reduced to rubble, the embedded rebar will be exposed and segregated from the 222 concrete rubble. In situations where a more surgical removal is required, activated and/or 223 contaminated concrete removal may be accomplished using a machine mounted, remote-224 operated articulating arm with interchangeable tooling heads. As concrete is fractured and rebar 225 exposed, the metal is cut using flame cutting equipment. The concrete rubble and exposed rebar 226 is collected and transferred into containers for later disposal in both techniques. Dusts, fumes 227 and generated debris are locally collected and as necessary, controlled using temporary 228 enclosures coupled with close-capture HEPA systems or controlled water misting systems. Bulk 229 concrete such as floors and walls may be removed as intact sections after sawing with blades, 230 wires or other cutting methods.
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 231 4.2.1.10. Additional Remedial Actions 232 Mechanical abrasive equipment, such as hones, may be used to remove contamination from the 233 surfaces of embedded/buried piping. Chemical removal means may be used, as appropriate, for 234 the removal of certain contaminants.
235 4.2.2. Soil 236 The surface and subsurface soil DCGLw that will be used to demonstrate compliance with the 237 dose-based criteria of 10 CFR 20, Subpart E for the unrestricted release of open land survey units 238 are provided in Tables 5-4 and 5-5 of Chapter 5. Section 2.5.1.1 of NUREG-1575, Multi-239 Agency Radiation Survey and Site Investigation Manual (MARSSIM) (Reference 4-6) 240 addresses the concern for the presence of small areas of elevated radioactivity. A simple 241 comparison to an investigation level is used to assess the dose impact of potential elevated areas.
242 This is referred to as the Elevated Measurement Comparison (EMC). The investigation level for 243 this comparison is the DCGLEMC, which is the DCGLw modified by an Area Factor (AF) to 244 account for the small area of the elevated radioactivity. Any radiological contamination in soils 245 identified in concentrations greater than the DCGLEMC will be removed and disposed of as 246 radioactive waste.
247 The site characterization process has established the location and extent of soil contamination at 248 ZNPS. Characterization survey results and historical survey data indicate that there is minimal 249 residual radioactivity in soil and no groundwater contamination identified to date. As needed, 250 additional investigations will be performed to ensure that any changing soil radiological 251 contamination profile during the remediation actions is adequately identified and addressed.
252 Chapter 5 discusses soil sampling and survey methods.
253 Soil remediation equipment will include, but not be limited to, shovels, back hoe and track hoe 254 excavators. Other equipment including soil dredges and vacuum trucks may also be used. As 255 practical, when the remediation depth approaches the soil interface region between unacceptable 256 and acceptable contamination, a squared edge excavator bucket design or similar technique may 257 be used. This simple methodology minimizes the mixing of contaminated soils with acceptable 258 lower soil layers as would occur with a toothed excavator bucket.
259 Remediation of soils will be performed using established excavation safety and environmental 260 control procedures. Operational constraints and dust control will be addressed in site excavation 261 and soil control procedures. In addition, work package instructions for remediation of soil may 262 include additional constraints and mitigation or control methods to ensure adequate erosion, 263 sediment, and air emission controls during soil remediation.
264 4.3. Remediation Activities Impact on the Radiation Protection Program 265 The Radiation Protection Program approved for decommissioning at ZSRP is similar to the 266 regulatory approved program that was implemented during commercial power operation and the 267 subsequent SAFSTOR period. During these periods, in a manner similar to remediation 268 activities during decommissioning, contaminated structures, systems and components were 269 decontaminated in order to perform maintenance or repair actions.
270 The current approved Radiation Protection Program at ZSRP is adequate to comply with all 271 federal and state regulatory requirements for the protection of occupational personnel from 4-6
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 272 radiological hazards encountered or expected to be encountered during the decommissioning of a 273 two unit commercial reactor facility. In addition, the program ensures the protection of the 274 public from radiological hazards and ensures occupational, effluent and environmental dose from 275 exposure to radioactive materials is, and remains ALARA. To ensure that adequate and proper 276 engineering controls and hazard mitigation techniques are employed, work control programs and 277 procedural requirements allow radiation protection personnel to integrate radiation protection 278 and radiological hazard mitigation measures directly into the work planning and scheduling 279 process. Consequently, the necessary radiological controls are correctly implemented to 280 accommodate each remediation technology as appropriate.
281 The spread of loose surface contamination is mitigated by the routine remediation of work areas 282 by washing and wiping. Water washing with a detergent is effective in reducing low levels of 283 loose surface contamination over large surface areas. Wiping with detergent soaked or oil-284 impregnated media is an effective technique to reduce loose surface contamination on small 285 items, overhead spaces and small hand tools. These same techniques are also effective in 286 reducing low levels of surface contamination on structural surfaces.
287 For intermediate levels of surface contamination, more aggressive methods such as pressure 288 washing, high-pressure water blasting and grit blasting may be more appropriate. Pipes, surfaces 289 and drain lines can be cleaned and hot spots removed using these techniques and technologies.
290 Small tools, hoses and cables can also be pressure washed in a containment to reduce 291 contamination levels. A paint coating may be applied after surface cleaning to prevent surface 292 contamination from drying out and becoming airborne.
293 To mitigate high levels of fixed surface contamination embedded in concrete, scabbling or other 294 surface removal techniques may be appropriate. A combination of mechanical and flame cutting 295 will be used to section the reactor vessel and its internals.
296 The Radiation Protection Program approved for decommissioning is similar to the program in 297 place during commercial power operation. During power operations, contaminated structures, 298 systems and components were decontaminated in order to perform maintenance or repair actions.
299 These techniques are the same or similar to the radiological controls implemented at ZSRP for 300 the decommissioning to reduce personnel exposure to radiation and contamination and to prevent 301 the spread of contamination from established contaminated areas. Concrete cutting or surface 302 scabbling, mechanical cutting, abrasive water jet cutting, hydrolazing and grit blasting has been 303 used at ZNPS in the past during operations. The current Radiation Protection Program provides 304 adequate controls for these actions.
305 Decommissioning does not present any new challenge to the Radiation Protection Program 306 above those encountered during normal plant operation and refueling. Decommissioning 307 planning allows radiation protection personnel to focus on each area of the site and plan each 308 activity well before execution of the remediation technique.
309 The decommissioning organization is experienced in and capable of applying these remediation 310 techniques on contaminated systems, structures or components during decommissioning. The 311 Radiation Protection Program is adequate to safely control the radiological aspects of this work.
312 Because the activities expected during decommissioning are the same or similar to those 313 encountered during operations, as described above, the approval of any changes to the existing 314 approved Radiation Protection Program as described in the Nuclear Regulatory Commission 4-7
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 315 (NRC) Docket Number 50-295, Facility Operating License Number DPR-39 (for Unit One) 316 (Reference 4-7), NRC Docket Number 50-304, Facility Operating License Number DPR-48 317 (for Unit Two) (Reference 4-8) is not requested in this LTP.
318 4.4. ALARA Evaluation 319 Guidance for conducting ALARA analyses is provided in Appendix N of NUREG-1757, 320 Volume 2, Revision 1, Consolidated Decommissioning Guidance - Characterization, Survey, 321 and Determination of Radiological Criteria, Final Report (Reference 4-9), which describes 322 acceptable methods for determining when further reduction of residual radioactivity is required 323 to concentrations below the levels necessary to satisfy the 25 mrem/yr dose criterion.
324 The surface and subsurface soil DCGLw that will be used to demonstrate compliance with the 325 25 mrem/yr dose criterion are provided in Tables 5-4 and 5-5 of Chapter 5. Characterization 326 survey results and historical survey data indicate that there is minimal residual radioactivity in 327 soil at ZNPS. Throughout the course of the decommissioning and through to site closure, ZSRP 328 will continue to survey and characterize soils as they are exposed by excavation during building 329 demolition or made accessible by the removal of structures or components. If residual 330 radioactivity is discovered at concentrations greater than the DCGLEMC in surface or subsurface 331 soils, ZSRP will excavate, package and dispose of the soil as Low-Level Radioactive Waste 332 (LLRW).
333 Section N.1.5 of NUREG-1757 states that For residual radioactivity in soil at sites that may 334 have unrestricted release, generic analyses show that shipping soil to a low-level waste disposal 335 facility is unlikely to be cost effective for unrestricted release, largely because of the high costs 336 of waste disposal. Therefore shipping soil to a low-level waste disposal facility generally does 337 not have to be evaluated for unrestricted release. To illustrate that this is a reasonable 338 approach and applicable to ZSRP, a simple ALARA analysis for the excavation and disposal of 339 soils as low-level radioactive waste is provided in section 4.4.1.
340 For the subsurface structures that will remain at license termination, the ALARA analysis will 341 determine whether further concrete remediation is necessary by comparing the desired beneficial 342 effects to the undesired costs. Benefits are the averted collective radiation dose (converted into 343 dollars) following the removal of radioactivity. The costs of remediation include transportation 344 accidents, worker and public dose associated with remedial action, and the actual costs to 345 perform the remediation (converted into dollars). If the costs exceed the benefits, then the dose 346 reduction achieved by further remediation is not ALARA.
347 The ALARA criterion specified in 10 CFR 20.1402 is not met by solely performing remediation.
348 The ALARA analysis is a planning tool to justify that further remediation is not necessary.
349 When remediation is performed, there is no need to analyze whether the action was necessary to 350 meet the ALARA requirement. The remediation required to meet the open air demolition criteria 351 specified in TSD 10-002, including cleaning loose surface contamination to concentrations 352 below 1,000 dpm/100cm2 and the remediation of concrete surfaces to meet the 2 mR/h exposure 353 rate criteria, will be performed regardless of the outcome of the ALARA evaluation.
354 Consequently, this is an example of when a remediation action is not required to be evaluated for 355 ALARA.
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 356 The methods and results of the ALARA evaluation for concrete remediation in structures below 357 588 foot elevation is provided in section 4.4.2.
358 4.4.1. ALARA Analysis of Soil Remediation 359 In order to determine if additional remedial action is warranted by ALARA analysis, the desired 360 beneficial effects (benefits) and the undesirable effects (costs) must be calculated. If the benefits 361 from remedial action will be greater than the costs, then the remedial action is warranted and 362 should be performed. However, if the costs exceed the benefit, then the remedial action is 363 considered to be not ALARA and should not be performed.
364 Based upon a simple ALARA analysis, the only benefit of reducing residual radioactivity in soil 365 is the monetary value of the collective averted dose to future occupants of the site. For soils, the 366 averted dose is based upon the resident farmer scenario.
367 4.4.1.1. Calculation of Benefits 368 The benefit from collective averted dose (BAD) is calculated by determining the present worth of 369 future collective averted dose and multiplying by a factor to convert the dose to a monetary 370 value. In accordance with Appendix N of NUREG-1757, the equation is as follows; 371 Equation 4-1 372 = $2,000 x ( )
373 where; 374 BAD = benefit from an averted dose for a remediation action, in 375 US dollars, 376 $2,000 = value in dollars of a person-rem averted and, 377 PW(ADCollective) = present worth of a future collective averted dose.
378 The present worth of future collective averted dose PW(ADCollective) is then expressed in 379 accordance with the following equation; 380 Equation 4-2
(+)
1 381 ( ) = ( )()(0.025)()
+
382 where; 383 PD = population density for the critical group scenario in 384 people/m2, 385 A = area being evaluated in square meters (m2),
386 0.025 = annual dose to an AMCG from residual radioactivity at the 387 DCGLw concentration in rem/yr, 388 F = effectiveness, or fraction of the residual radioactivity 389 removed by the remediation action, 4-9
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 390 Conc = average concentration of residual radioactivity in the area 391 being evaluated in units of activity per unit volume (pCi/g),
392 DCGLw = derived concentration equivalent to the average 393 concentration of residual radioactivity that would give a 394 dose of 25 mrem/yr to the AMCG (pCi/g),
395 r = monetary discount rate in units per year (yr-1),
396 = radiological decay constant for the radionuclide in units per 397 year and, 398 N = number of years over which the collective dose will be 399 calculated.
400 4.4.1.2. ALARA Analysis Parameters 401 In accordance with Table N.2 of Appendix N of NUREG-1757, the acceptable and relevant 402 parameters for use in performing ALARA analysis are as follows; 403
- Dollars per person-Rem rem - $2,000.00/person-rem (per NUREG/BR-0058, Regulatory 404 Analysis Guidelines of the U.S. Nuclear Regulatory Commission [Reference 4-10])
405
- Population density (PD) for the critical group (persons/m2) - 0.0004 person/m2 for land (per 406 NUREG-1496, Final Generic Environmental Impact Statement in Support of Rulemaking 407 on Radiological Criteria for License Termination of NRC-Licensed Nuclear Facilities, 408 Volume 2, [Reference 4-11] Appendix B, Table A.1) 409
- Monetary discount rate (r) - 0.00 yr-1 for soilMonetary discount rate (r) - 0.03 yr-1 for soil 410 (per NUREG/BR-0058) 411 (Note:; This variable was established at 0.03 yr-1 for soil in Table N.2 of Appendix N of 412 NUREG-1757. The monetary discount for the ALARA analysis was removed from the 413 equation through Federal Register Notice 72 FR 46102 - August 16, 2007. Consequently, 414 the r variable has been conservatively set at 0.00 yr-1 for soil, i.e., no monetary discount for 415 soils as well as basements.)
416
- Area (A) used to calculate the population density (m2) - 10,000 m2 (size of reference area 417 that was evaluated) 418
- Number of years (N) over which the collective averted dose is calculated (yr) - 1,000 yrs (per 419 NUREG-1496, Volume 2, Appendix B, Table A.1) 420 4.4.1.3. Calculation of Costs 421 The total cost, (CostT) which is balanced against the benefits; has several components and may 422 be evaluated according to Equation N-3 of NUREG-1757, Appendix N below:
423 Equation 4-3 424 = + + + + +
425 where:
4-10
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 426 CostR = monetary cost of the remediation action (including 427 mobilization costs);
428 CostWD = monetary cost for transport and disposal of the waste 429 generated by the action; 430 CostACC = monetary cost of worker accidents during the remediation 431 action; 432 CostTF = monetary cost of traffic fatalities during transportation of 433 the waste; 434 CostWDose = monetary cost of traffic fatalities during transportation of 435 the waste; 436 CostPDose = monetary cost of dose to the public from excavation, 437 transport and disposal of the waste; 438 4.4.1.4. Calculation of Total Cost for Soil Remediation by Excavation and Disposal 439 For the analysis of soil excavation and disposal as low-level radioactive waste, the variables for 440 CostR, CostACC, CostWDose and CostPDose were not calculated for this evaluation based upon their 441 anticipated unlikely impact on the total cost (CostT). This is consistent with the guidance 442 provided in NUREG-1757 which states that if one or two of the costs can be shown to exceed the 443 benefit, then the remediation cost is shown to be unnecessary without calculating all of the costs.
444 4.4.1.4.1. Transport and Disposal of the Waste (CostWD) 445 The cost of waste transport and disposal (CostWD) was calculated using Equation N-4 of 446 NUREG-1757, Appendix N which is expressed as follows:
447 Equation 4-4 448 = x 449 where:
450 VA = volume of waste produced, remediated in units of m3; 451 CostV = cost of waste disposal per unit volume, including 452 transportation cost, in units of $/m3.
453 Disposal costs for generated waste were based on an average total disposal cost of $2,500/m3.
454 This average cost includes packaging, transportation and disposal fees. The transportation 455 component of this average cost is based on the average transportation cost of using either rail or 456 highway hauling from the Zion site to Clive, Utah (EnergySolutions radioactive waste disposal 457 facility). The details of the average total disposal cost (CostV) of $2,500/m3 of waste are 458 considered proprietary values defined by negotiated contract.
459 The volume of waste produced by remediation (VA) assumes that the reference area of 10,000 m2 460 (A) is remediated to a depth of 0.15 meters. This results in a value for waste volume (VA) of 461 1,500 m3, which produces a value for CostWD of $3,750,000.00.
4-11
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 462 4.4.1.4.2. Transportation Risks (CostTF) 463 The cost of traffic fatalities incurred during the transportation of waste (CostTF) was calculated 464 using Equation N-6 of NUREG-1757, Appendix N which is expressed as follows:
465 Equation 4-5 466 =$3,000,000 x x x 467 where:
468 $3,000,000 = monetary value of a fatality equivalent to $2000/person-469 rem (NUREG-1530 Reassessment of NRCs Dollar per 470 Person-Rem Conversion Factor Policy [Reference 4-12])
471 VA = volume of waste produced in units of m3; 472 VSHIP = volume of a truck shipment in m3; 473 FT = fatality rate per truck-kilometer traveled in units of 474 fatalities/truck-km; 475 DT = distance traveled in km.
476 For this evaluation, the waste volume (VA) is assumed to be 1,500 m3 and the haul volume of an 477 overland truck shipment per NUREG-1757 is assumed to be 13.6 m3 (VSHIP).
478 In accordance with NUREG-1496, Appendix B, Table A.1, a value of 3.8 E-08/hr was used for 479 FT.
480 The Clive, Utah round trip distance from the Zion site by highway is 1,463 miles (2,355 km).
481 The distance for rail shipments is further than that for highway shipments because of the route 482 rail shipments must follow, however the difference as it pertains to the calculation is 483 insignificant. The highway shipment distance of 2,355 km (DT) was used for the calculation of 484 CostTF. For this evaluation, the value for the CostTF variable is $29,610.66.
485 4.4.1.4.3. Total Cost (CostT) 486 The total cost, (CostT) assumed for this evaluation is $3,779,610.66.
487 4.4.1.5. Residual Radioactivity in Soils that are ALARA 488 Determination of residual radioactivity in soils that are ALARA is the concentration at which 489 benefit equals or exceeds the costs of removal and waste disposal. When the total cost (CostT) is 490 set equal to the dose averted, the ratio of the concentration to the DCGLw is calculated as 491 follows; 492 Equation 4-6
( )( + )
493 =
($2,000)( )(0.025)()()(1 (+) )
494 Assuming the following values for the remaining variables; 4-12
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 495
- the default parameter values from section 4.4.1.2, 496
- a value of one for remediation effectiveness (F), assuming all residual radioactivity is 497 removed during the excavation, 498
- a surface soil DCGLw of 1514.18 pCi/g for Cs-137 from Table 5-4 of Chapter 5, 499 Equation 4-7 0.693
($3,779,610.66) 0.030 +
500
= 30.17 0.693
($2,000)(0.0004)(0.025)(1)(10,000) 1 0.030+30.171,000 501 the ratio of the concentration to the DCGLw when the total cost (CostT) is equal to the dose 502 averted is 1,001.03434.08.
503 Assuming a concentration set at 50% of the DCGLw (based on the investigation level for a 504 Class 3 area), the present worth of future collective averted dose PW(ADCollective) can be 505 calculated as follows; 506 Equation 4-8 507 ( )
0.693 0.030+ (1,000) 7.09 1 30.17 508 = (0.0004)(10,000)(0.025)(1) 15.814.2 0.693 0.030 + 30.17 509 resulting in a value for PW(ADCollective) of 0.942.18 person rems. The benefit from collective 510 averted dose (BAD) is then calculated as follows; 511 Equation 4-9 512 = $2,000 x 0.942.18 = $14,880353.0054 513 This simple analysis confirms the statement in section N.1.5 of NUREG-1757 that the cost of 514 disposing excavated soil as low-level radioactive waste is clearly greater than the benefit of 515 removing and disposing of soil with residual radioactivity concentrations less than the dose 516 criterion. Since the cost is greater than the benefit, it is not ALARA to excavate and dispose of 517 soils with residual radioactivity concentrations below the DCGLw.
518 4.4.2. ALARA Analysis for Remediation of Basement Structures 519 With the exception of some penetrations, embedded and buried piping, all contaminated and 520 non-contaminated systems will be disassembled, removed, packaged and shipped off-site as a 521 waste stream commodity. The list of penetrations and embedded piping to remain is provided in 522 ZionSolutions TSD 14-016,14-016, Description of Embedded Pipe, Penetrations, and Buried 523 Pipe to Remain in Zion End State (Reference 4-13). Once commodity removal is complete, 524 structural surfaces will be remediated as necessary to meet the open air demolition criteria 525 specified in TSD 10-002. These criteria provide the removable contamination levels and contact 526 exposure rates that will allow structures to be safely demolished without containment. Prior to 527 demolition, a contamination verification survey (CVS) will be performed to identify areas 4-13
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 528 requiring remediation to meet the open-air demolition limits. The CVS will also be used to 529 identify areas on surfaces to remain at license termination (i.e., at least three feet below grade) 530 that could potentially result in a FSS measurement (using ISOCS) to exceed the Basement 531 DCGLs (DCGLB) listed in LTP Chapter 5, Table 5-3. The dose rate target for this objective will 532 be lower than that required for open-air demolition. Identified areas will be remediated to 533 provide high confidence that no FSS ISOCS measurement will exceed the DCGLB. These 534 conditions or indicators are designations used to characterize the acceptable removable 535 contamination and contact exposure rates that will safely allow structures to be demolished 536 without containment. The limits are based upon re-suspension factors and ground level release 537 and dispersion models. Public dose is calculated at the site boundary using Off Site Dose 538 Calculation Manual (ODCM) methodologies for a ground level airborne radioactivity release.
539 The objectives of the open air demolition limits are:
540 To ensure ground level airborne radioactivity levels remain ALARA and within regulatory limits 541 (note that in this case, ALARA refers to operational ALARA and not 10 CFR 20.1402 542 compliance).
543 To ensure demolition liquid concentrations remain at levels which can be collected, processed 544 and released using plant water treatment systems and discharge points.
545 To minimize the spread of contamination within the site boundary such that there is not 546 significant effect on groundwater or the scope of soil remediation required for License 547 Termination.
548 To ensure open air demolition activities can be conducted using conventional demolition 549 techniques with minimal radiological restrictions or controls.
550 Based upon the calculations, comparison and conclusions documented in TSD 10-002, the 551 following open air demolition limits will be implemented:
552 Less than 2 mR/hr beta-gamma total contamination on contact with structural concrete.
553 Less than 1,000 dpm/100cm2 beta-gamma loose surface contamination.
554 All structural surfaces will be remediated to the open air demolition limits prior to demolition.
555 Confirmatory surveys will be performed using approved procedures following remediation and 556 prior to demolition to ensure that contamination levels are at or below the open are demolition 557 criteria. It is expected that remediation to open air demolition criteria will reduce the structure 558 source terms to level below that corresponding to 25 mrem/yr. If not, additional remediation will 559 be performed to meet the 25 mrem/yr dose limit. Once remediation is complete structural 560 surfaces located above the 588 foot elevation and non-load-bearing interior concrete walls below 561 the 588 foot elevation will be demolished, reduced in size, packaged and shipped off-site to a 562 licensed disposal facility.
563 All concrete inside the liner above the 541565 foot elevation will be removed from the interiors 564 of both Containment Buildings prior to demolition. This includes all activated and contaminated 565 concrete. Only the concrete below the 541565 foot elevation in the In-core Instrument Shaft 566 leading to and including the area under vessel (or Under-Vessel area) will remain. The source 567 term in the Containment Basements remaining after demolition will be consist of the concrete in 568 the Under-Vessel area(s) and low levels of surface contamination on the exposed liner surfaces.
569 There is currently minimal contamination in the Turbine Building, Crib House/Forebay, and 4-14
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 570 Circulating Water Piping at levels that are expected to be well below the open air demolition 571 criteria and below the DCGLB listed in LTP Chapter 5, Table 5-3.contamination levels 572 corresponding to 25 mrem/yr dose limit in the BFM (see Chapter 6 for a detailed description of 573 the BFM). The only portion of the Fuel Handling Building Basement that will remain following 574 building demolition is the lower 13 foot (~4 m) concrete bottom of the Spent Fuel Pool (SFP) 575 and the Transfer Canal, which is located at the 575 foot elevation. The steel liner will be 576 removed from both the SFP and the Transfer Canal. After the liner is removed and the 577 underlying concrete exposed, additional continuing characterization surveys will be performed to 578 assess the radiological condition of the underlying concrete pad and remaining pool walls.
579 Continuing characterization will consist of scanning of the exposed concrete surfaces and the 580 acquisition of concrete core sample(s) at the location of highest activity. Contamination is 581 expected below the liner but an estimate of levels cannot be made until characterization is 582 completed.
583 In summary, the vast majority of residual radioactivity remaining in the structures after the open 584 air demolition criteria is met and after the majority ofall concrete is removed from the 585 Containment Building basements will be located in the 542 foot elevation floor of the Auxiliary 586 Building. Therefore, the ALARA assessment for the remediation of basement structures will 587 focus on the 542 foot elevation floor of the Auxiliary Building as this is the location were the 588 greatest benefit of concrete remediation could be achieved. An ALARA assessment of the 589 542 foot elevation floor of the Auxiliary Building will bound ALARA assessments for the other 590 buildings which would use the same methods (and cost estimate) but remove less contamination.
591 If continuing characterization indicates significant concentrations of residual radioactivity 592 remaining in other end-state structures (e.g., Under-Vessel area, SFP/Transfer Canal, Auxiliary 593 Building embedded drains), then ZSRP will perform and document a separate ALARA analysis 594 or, provide evidence that the ALARA analysis of the 542 foot floor of the Auxiliary Building is 595 still bounding.
596 The Auxiliary Building basement concrete at the 542 foot elevation is volumetrically 597 contaminated. A total of twenty (20) concrete core samples were collected in the Auxiliary 598 Building during characterization. The sample analysis of these concrete core samples indicates 599 that the majority of the radionuclide inventory resides within the first 1/2-inch of concrete.
600 However, several core samples show detectable Cs-137 and Co-60 at depths in excess of six 601 inches.
602 4.4.2.1. ALARA Analysis Equation for Remediation of Basement Structures 603 For the ALARA analysis for the remediation of basement structures, the equation from section 604 4.4.1.5 for the ratio of the concentration to the DCGLw when the total cost (CostT) is set equal to 605 the dose averted is modified as follows. The BFM DFsDCGLs for concrete are expressed in 606 units of mrem/yr per mCi total activitypCi/m2. The denominator must be summed and the 607 individual dose contribution normalized to account for the multiple detectable radionuclides that 608 are present in the radionuclide distribution for the Auxiliary Building. The equation from 609 NUREG-1757 therefore becomes:
4-15
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 610 Equation 4-10
( )( + )
611 =
($2,000) ( )( )( 0.025)()()(1 (+ ) )
612 where:
613 fi = the normalized product of the Basement Inventory 614 Levelsradionuclide fraction for the Auxiliary Building for 615 each individual Radionuclides of Concern (ROC) (from 616 Chapter 5, Table 5-92) normalized to one 617 DOSEAMCG = averted dose to the AMCG (rem).
618 The total cost for the remedial action when divided by the total benefit of averted dose 619 determines the cost effectiveness of the remedial action. Values greater than unity demonstrate 620 that no further remediation is necessary beyond that required to meet the 25 mrem/yr dose 621 criterion and are ALARA. Values less than one provide the fraction of the 25 mrem/yr dose 622 criterion where it is necessary to remediate to achieve ALARA.
623 4.4.2.2. Remedial Action Costs 624 The only structures that will remain as potential candidate surfaces for remediation are the 625 concrete walls and floors from the Auxiliary Building, the Under-Vessel area(s), Turbine 626 Building, Crib House/Forebay, WWTF, the lower 13 foot concrete bottom of the SFP, the 627 Circulating Water Intake Piping and Circulating Water Discharge Tunnels. With the exception 628 of some sections of buried and embedded pipe, all impacted systems, components as well as all 629 structures above the 588 foot elevation will be removed during the decommissioning process and 630 disposed of as a waste stream. The current decommissioning approach for ZSRP also calls for 631 the beneficial reuse of concrete from building demolition as clean fill. As discussed above, the 632 vast majority of contamination to remain after removal of containment concrete will be in the 633 542 foot elevation floor of the Auxiliary Building.
634 Prior to building demolition, all structures will be remediated to meet the open air demolition 635 limits specified in TSD 10-002 and, to provide high confidence that ISOCS measurements taken 636 during FSS will not exceed the DCGLB from Table 5-3. All loose surface contamination greater 637 than 1,000 dpm/100cm2 will be removed. The remediation techniques most likely to be 638 implemented to perform this work are vacuuming, pressure washing and hand-wiping,. In 639 addition, TSD 10-002 calls for structural surfaces that exhibit fixed contamination in excess of 640 2 mR/hr beta-gamma total surface contamination on contact to be remediated. The remediation 641 approach used to accomplish this action will likely be concrete scabbling or concrete shaving.
642 As these efforts will occur prior to evaluating the remaining structural surfaces for acceptable 643 concentrations of residual activity, this remediation action will not be evaluated for ALARA.
644 The remediation action evaluated for the ALARA analysis for the remediation of basement 645 structures is scabbling the concrete surface of the 542 foot elevation floor of the Auxiliary 646 Building. Concrete core samples indicate that the majority of the radionuclide source inventory 647 in the 542 foot elevation concrete floor resides within the first 1/2-inch of concrete. For the 648 purposes of the ALARA evaluation, it is conservatively assumed that 100% of the contamination 649 resides in the first 1/2 inch. In accordance with the guidance in section G.3.1 of NUREG/CR-4-16
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 650 5884, Revised Analyses of Decommissioning for the Reference Pressurized Water Reactor 651 Power Station Volume 2 (Reference 4-1314), one pass of scabbling is assumed to remove 652 0.125 inches (0.635 cm) of concrete. In accordance with ZionSolutions TSD 14-013, Zion 653 Auxiliary Building End State Estimated Concrete Volumes, Surface Areas, and Source Terms 654 (Reference 4-1415), the 542 foot elevation floor of the Auxiliary Building has a surface area of 655 2,543 m2. This is the surface area which will be evaluated for the remediation cost 656 determination.
657 4.4.2.2.1. Remediation Activity Rates 658 The remediation activity rates that were used for this evaluation were based on previous 659 experience, from published literature, or from groups or vendors currently performing these or 660 similar activities. Current project labor costs and past operational experience were also used in 661 developing these rates.
662 In accordance with NUREG/CR-5884, an assumed crew size for performing concrete scabbling 663 or shaving activities is three full-time laborers, a supervisor at a 1/4-time involvement and a 664 Radiation Protection Technician (RPT), also at a 1/4-time involvement. Using the current project 665 labor rates for these positions of $66.78 per hour for a laborer, $90.00 per hour for a supervisor 666 and $55.59 per hour for a RPT, the hourly unit rate that will be used for the evaluation is 667 $236.74.
668 Using the guidance found in NUREG/CR-5884 it is assumed that the concrete scabbling or 669 shaving activity will remove approximately 0.125 inches of concrete per pass and the effective 670 nominal removal rate is approximately 12.07 m2 per hour. The ALARA evaluation assumes that 671 100% of the radioactive contamination resides within the first 1/2 inch. Consequently, removing 672 1/2 inch of concrete over an assumed reference area of 2,543 m2, scabbling at a nominal rate of 673 12.07 m2 per hour to a depth of 0.125 inch per pass, equates to approximately 836.5 man-hours 674 of work.
675 Also in accordance with NUREG/CR-5884 it is assumed that the actual remediation time in a 676 typical eight-hour shift is 5.33 hours3.819444e-4 days <br />0.00917 hours <br />5.456349e-5 weeks <br />1.25565e-5 months <br />. To account for non-remediation work hours for work 677 preparation, donning and removing protective clothing and work breaks, the total man-hours 678 were increased by a factor of 33% which equates to 1,112 man-hours. In addition, a contingency 679 of 25% was added to the manpower hours. This equates to a total man-hours of 1,390.61 man-680 hours, which is multiplied times the hourly unit rate of $236.74 to equal the labor cost for this 681 evaluation of $329,209.54.
682 4.4.2.2.2. Equipment Costs 683 Using the guidance found in NUREG/CR-5884, equipment costs are based on the rental of 684 commercially available scabbing equipment, a compressor, a vacuum unit and consumables such 685 as cutting bits, vacuum filters and waste drums for containing waste debris. At 40-hours per 686 work week, 1,391 man-hours equates to approximately 35 work-weeks. This evaluation assumes 687 that two different commercially available concrete removal units will be procured, the Pentek 688 Squirrel Scabbler & Vacuum System with a nominal rental rate of $685.00 per week and a 689 Pentek Moose Scabbler & Vacuum System with a nominal rental rate of $950.00 per week. The 690 compressor required for pneumatic equipment operation can be rented at a nominal rate of 691 $115.00 per week. The cutting bits for the units are assumed to be replaced every 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br /> of 4-17
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 692 operation, for an equivalent cost of about $13.00 per hour of operation. Additional costs include 693 filter replacements at about $2.50 per hour of operation and waste drums for the collected debris.
694 A 55-gallon drum holds approximately 7 ft3 of waste and cost approximately $100.00 per drum.
695 As it is assumed that the scabbing activity will generate approximately 1,132 ft3 (32 m3) of 696 concrete waste, this will require the procurement of approximately 162 drums at a total cost of 697 $16,171.49. The mobilization and demobilization costs associated with procuring this equipment 698 would be approximately $2,200.00 per piece of equipment for a total of approximately 699 $6,600.00. The total equipment costs assumed for this evaluation is approximately $98,975.87.
700 4.4.2.2.3. Total Remediation Action Cost (CostR) 701 For the evaluation of the remediation activity of concrete scabbling or shaving, the sum of the 702 labor cost of $329,209.54 plus the equipment cost of $98,975.87 results in a total remediation 703 action cost (CostR) for this activity of $428,185.41.
704 4.4.2.3. Transport and Disposal of the Waste (CostWD) 705 As previously described in section 4.4.1.4.1, the cost of waste transport and disposal (CostWD) is 706 expressed as follows:
707 Equation 4-11 708 = x 709 Disposal costs for generated waste were based on an average total disposal cost of $2,500/m3.
710 This average cost includes packaging, transportation and disposal fees. The transportation 711 component of this average cost is based on the average transportation cost of using either rail or 712 highway hauling from the Zion site to Clive, Utah (EnergySolutions radioactive waste disposal 713 facility). Based upon an assumed waste volume of 32 m3, a value of $80,000.00 is calculated for 714 the CostWD variable.
715 4.4.2.4. Non-Radiological Risks (CostACC) 716 The cost of non-radiological workplace accidents (CostACC) was calculated using Equation N-5 717 of NUREG-1757, Appendix N which is expressed as follows:
718 Equation 4-12 719 =$3,000,000.00 x x 720 where:
721 $3,000,000 = monetary value of a fatality equivalent to $2000/person-722 rem (NUREG-1530) 723 FW = workplace fatality rate in fatalities/hour worked; 724 TA = worker time required for remediation in units of worker-725 hours.
726 In accordance with NUREG-1496, Appendix B, Table A.1, a value of 4.2 E-08/hr was used for 727 FW. For TA, in accordance with NUREG-1757 the same hours that was determined for labor cost 4-18
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 728 (1,391 man-hours) was used for worker accident cost. Subsequently, a value of $175.27 is 729 calculated for the CostACC variable.
730 4.4.2.5. Transportation Risks (CostTF) 731 As previously described in section 4.4.1.4.2, the cost of traffic fatalities incurred during the 732 transportation of waste (CostTF) is expressed as follows:
733 Equation 4-13 734 =$3,000,000.00 x x x 735 For this evaluation, the waste volume (VA) is assumed to be 32 m3 and the haul volume of an 736 overland truck shipment per NUREG-1757 is assumed to be 13.6 m3 (VSHIP).
737 In accordance with NUREG-1496, Volume 2, Appendix B, Table A.1, a value of 3.8 E-08/hr 738 was used for FT.
739 The Clive, Utah round trip distance from the Zion site by highway is 1,463 miles (2,355 km).
740 The distance for rail shipments is further than that for highway shipments because of the route 741 rail shipments must follow, however the difference as it pertains to the calculation is 742 insignificant. The highway shipment distance of 2,355 km (DT) was used for the calculation of 743 CostTF. For this evaluation, the value for the CostTF variable is $631.69.
744 4.4.2.6. Worker Dose Estimates (CostWDose) 745 The cost of remediation worker dose (CostWDose) was calculated using Equation N-7 of NUREG-746 1757, Appendix N which is expressed as follows:
747 Equation 4-14 748 =$2,000.00 x x 749 where:
750 DR = total effective dose equivalent (TEDE) rate to remediation 751 workers in units of Remrem/hr; 752 T = time worked (site labor) to remediate the area in units of 753 person-hour.
754 Costs associated with worker dose are a function of the hours worked and the workers radiation 755 exposure for the task. A value of 3 mrem per man-hour was used for DR. This assumes that a 756 majority of the source inventory will be removed prior to performing the concrete scabbling or 757 shaving activity. The time worked to remediate the area in units of person-hour calculated for 758 this activity (T) was 1,391 man-hours. For this evaluation, the value for the CostWDose variable is 759 $8,346.00.
760 4.4.2.7. Monetary Cost of Dose to the Public (CostPDose) 761 The cost of remediation worker dose (CostPDose) was calculated using Equation N-7 of NUREG-762 1757, Appendix N which is expressed as follows:
4-19
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 763 Equation 4-15 764 =$2,000.00 x x 765 where:
766 DR = total effective dose equivalent (TEDE) rate to public in 767 units of Remrem/hr; 768 T = time spent near waste shipments in parking lots in units of 769 person-hour.
770 For this equation, a worst-case value of 0.5 mrem/hr was used for DR. This assumes that the 771 shipment is classified as Limited Specific Activity (LSA) in accordance with 49 CFR 173.427 772 and the package meets the Zion specific administrative limit of 0.5 mrem/hr on the exterior of 773 the shipment. The exposure time (T) used for this calculation is based upon a transit time of 774 23 hours2.662037e-4 days <br />0.00639 hours <br />3.80291e-5 weeks <br />8.7515e-6 months <br /> driving from Zion to the disposal site in Clive Utah times three shipments, for a total of 775 69 hours7.986111e-4 days <br />0.0192 hours <br />1.140873e-4 weeks <br />2.62545e-5 months <br />. For this evaluation, the value for the CostPDose variable is $69.00.
776 4.4.2.8. Total Cost (CostT) 777 The total cost, (CostT) assumed for this evaluation is $517,407.37 778 4.4.2.9. Residual Radioactivity in Basement Structures that are ALARA 779 The following parameters were used for performing the ALARA calculation using the equation 780 from NUREG-1757 and presented in section 4.4.2.1:
781
- Population density (PD) for the critical group (persons/m2) - 0.0004 person/m2 for soil (per 782 NUREG-1496, Appendix B, Table A.1) 783
- Fraction of residual radioactivity removed by the remedial action (F) - 1 (Removal of desired 784 concrete volume is assumed 100% effective) 785
- Area (A) used to calculate the population density (m2) -
786 o Groundwater scenario -10,000 m2 (size of resident farmer reference area) 787 o Drilling Spoils scenario - 100 m2 is assumed in order to allow the calculation to generate 788 a population of 1 person exposed to drilling spoils. The actual surface area of the drilling 789 spoils is much smaller at 0.46 m2 (see LTP Chapter 6) 790
- Monetary discount rate (r) - 0.00 yr-1 for soil 791 (Note; This variable was established at 0.03 yr-1 for soil in Table N.2 of Appendix N of 792 NUREG-1757. The monetary discount for the ALARA analysis was removed from the 793 equation through Federal Register Notice 72 FR 46102 - August 16, 2007. Consequently, 794 the r variable has been conservatively set at 0.00 yr-1 for soil, i.e., no monetary discount for 795 soils as well as basements.)Monetary discount rate (r) - 0.03 yr-1 for soils (per NUREG/BR-796 0058) 797
- Number of years (N) over which the collective averted dose is calculated (yr) - 1,000 yrs (per 798 NUREG-1496, Appendix B, Table A.1) 4-20
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 799 4.4.2.9.1. Radionuclides Considered for ALARA Analysis 800 The radionuclide mixture for contaminated concrete developed in ZionSolutions TSD 14-019, 801 Radionuclides of Concern for Soil and Basement Fill Model Source Terms (Reference 4-1516) 802 was used for the ALARA analysis. The Basement Inventory LevelsDCGLB for the Auxiliary 803 Building for each individual ROC from Chapter 5, Table 5-9 3 were used for the calculation of fi.
804 DCGLs, in units of pCi/m2 of basement surface area, are presented in Chapter 6, section 6.6.8.1 805 for the Basement Fill Model (BFM) Groundwater and BFM Drilling Spoils scenarios 806 individually and are designated as the DCGLBS (Basement Scenario DCGLs). The 807 DCGLBSBasement Inventory Levels for the Auxiliary Building are reproduced in Table 4-1.
808 The values for half-life, radiological decay constants () and the radionuclide mixture fractions 809 are presented in Table 4-2. The mixture fractions are based on the analysis of the concrete core 810 samples taken on the Auxiliary Building 542 foot elevation and presented in TSD 14-019, 811 Table 17.
812 The ALARA calculation was performed in two parts, the first representing the Groundwater 813 scenario and the second representing the Drilling Spoils scenario. Two dose values were 814 required to accurately calculate the averted dose because the compliance dose is based on the 815 sum of both scenarios. In addition, each scenario is applicable to a different area. The 816 Groundwater dose applies to the full 10,000 m2 site area, the Drilling Spoils dose applies only to 817 the area of material brought to the surface by the well drilling action.
818 The actual dose from each scenario, assuming a summation of the dose from both scenarios 819 equaled 25 mrem/yr is presented in Table 4-3. Therefore, the dose values for each ROC from 820 Table 4-3 were used to derive the AMCG (DOSEAMCG) variable in Equation 4-10 for each 821 scenario.
822 Table 4-1 Basement Inventory LevelsDCGLBS for the Auxiliary Building Inventory Drilling Spoils LimitGroundwat Scenario DCGL Radionuclide er Scenario DCGL (mCi)
(pCi/m2) (pCi/m2) 3.28E+102.28 Co-60 3.07E+08 E+03 1.15E+108.76 Ni-63 1.02E+14 E+04 9.98E+067.50 Sr-90 5.25E+10 E+01 3.55E+081.59 Cs-134 5.23E+08 E+03 1.25E+088.35 Cs-137 1.02E+09 E+02 4-21
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 823 824 4-22
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 825 Table 4-2 Radionuclide Half-Life(s), Decay Constant(s) and Dose FactorsMixture Half-Life Radionuclide Radionuclide (a)
(yrs) (yr-1) Mixture(b)
Co-60 5.27 E 00 1.31 E-01 0.92%
Ni-63 9.60 E+01 7.22 E-03 23.71%
Sr-90 2.91 E+01 2.38 E-02 0.05%
Cs-134 2.06 E+00 3.36 E-01 0.01%
Cs-137 3.02 E+01 2.30 E-02 75.32%
826 (a) Dose significant ROC for the Auxiliary Building in accordance with TSD 14-019.
827 (b) Normalized radionuclide mixture for dose significant ROC for Auxiliary Building from Table 20 of 828 TSD 14-019.
829 830 Table 4-3 Dose for Individual Scenarios (DOSEAMCG)
Auxiliary Building Groundwater Drilling Spoils (mrem/yr) (mrem/yr)
Co-60 0.232 24.768 Ni-63 24.997 0.003 Sr-90 24.995 0.005 Cs-134 14.892 10.108 Cs-137 22.271 2.729 831 832 4.4.2.9.2. ALARA Calculation 833 The ALARA calculations performed to evaluate the concrete scabbling or shaving remediation 834 activity is presented in Table 4-3 4 for the Auxiliary Building 542 foot elevation. A result for the 835 Conc/DCGL ratio that is less than one would justify remediation whereas a result greater than 836 one would demonstrate that residual radioactivity is ALARA. The Conc/DCGL ratio calculated 837 for the summation of In-Situ Scenarios (Groundwater + Drilling Spoils) was 2.87.
838 4.4.2.10. Conclusion 839 Concrete structural surfaces below the 588 foot elevation will remain in place after license 840 termination. The site dose contribution from remaining residual radioactivity remaining in these 841 buried plant structures will be accounted for by the BFM. The ALARA analysis based on cost 842 benefit analysis shows that further remediation of concrete beyond that required to demonstrate 843 compliance with the 25 mrem/yr dose criterion is not justified.
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 0 844 Table 4-4 ALARA Analysis for Volumetrically Contaminated Subsurface Structures - Auxiliary Building 542 ft.
845 Cost (in dollars) of remedial action (CostT) = $517,407.37 846 Summation of In-Situ Scenarios (Groundwater + Drilling Spoils) 847 (Groundwater Scenario) 848 A = 10,000 m2, r = 0.00 yr-1, N = 1,000 yr, PD = 0.01 person/m2 Fraction of Activity removed by remedial action (F) = 1 Column A Column B Column C Column D Column E Column F Column G Column H Column I Column J Column K Column L Column M fi Column Half-Life [1-e-(r+)N] GW (Columns Cost Nuclide (r+) (r+)N e-(r+)N 1-e-(r+)N Mixture b K divided (yrs)b (yr-1)b /(r+) DCGLBS a I*J) Benefit by sum Co-60 5.27E+00 1.31E-01 1.31E-01 1.31E+02 7.77E-58 1.00E+00 7.60E+00 0.92% 3.28E+10 3.02E+08 9.66E-02 $ 179.22 Ni-63 9.60E+01 7.22E-03 7.22E-03 7.22E+00 7.33E-04 9.99E-01 1.38E+02 23.71% 1.15E+10 2.73E+09 8.73E-01 $ 174,620.71 Sr-90 2.91E+01 2.38E-02 2.38E-02 2.38E+01 4.54E-11 1.00E+00 4.20E+01 0.05% 9.98E+06 4.99E+03 1.60E-06 $ 0.32 Cs-134 2.06E+00 3.36E-01 3.36E-01 3.36E+02 7.94E-147 1.00E+00 2.97E+00 0.01% 3.55E+08 3.55E+04 1.14E-05 $1.35 Cs-137 3.02E+01 2.29E-02 2.29E-02 2.29E+01 1.08E-10 1.00E+00 4.36E+01 75.31% 1.25E+08 9.41E+07 3.01E-02 $ 5,371.22 Check Sum 100% Sum 3.12E+09 1.00E+00 $ 180,172.82 (CostB) 849 (Drilling Spoils Scenario) 850 A = 100.00 m2 (c), r = 0.00 yr-1, N = 1,000 yr, PD = 0.01 person/m2 Fraction of Activity removed by remedial action (F) = 1 Column A Column B Column C Column D Column E Column F Column G Column H Column I Column J Column K Column L Column M fi Column Half-Life [1-e-(r+)N] DS (Columns Cost Nuclide (r+) (r+)N e-(r+)N 1-e-(r+)N Mixture b K divided (yrs)b (yr-1)b /(r+) DCGLBS a I*J) Benefit by sum Co-60 5.27E+00 1.31E-01 1.31E-01 1.31E+02 7.77E-58 1.00E+00 7.60E+00 0.92% 3.07E+08 2.82E+06 1.17E-07 $ 0.00 Ni-63 9.60E+01 7.22E-03 7.22E-03 7.22E+00 7.33E-04 9.99E-01 1.38E+02 23.71% 1.02E+14 2.42E+13 1.00E+00 $ 0.23 Sr-90 2.91E+01 2.38E-02 2.38E-02 2.38E+01 4.54E-11 1.00E+00 4.20E+01 0.05% 5.25E+10 2.63E+07 1.09E-06 $ 0.00 Cs-134 2.06E+00 3.36E-01 3.36E-01 3.36E+02 7.94E-147 1.00E+00 2.97E+00 0.01% 5.23E+08 5.23E+04 2.16E-09 $ 0.00 Cs-137 3.02E+01 2.29E-02 2.29E-02 2.29E+01 1.08E-10 1.00E+00 4.36E+01 75.31% 1.02E+09 7.68E+08 3.18E-05 $ 0.01 Check Sum 100% Sum 2.42E+13 1.00E+00 $ 0.23 (CostB)
Summation of In-SituInsitu Cost Benefit (Groundwater + Drilling Spoils)
Conc/ DCGL (A result < 1 would justify remediation whereas a result > 1 would demonstrate that residual radioactivity is ALARA) 2.87 851 (a) From Table 4-1 852 (b) From Table 4-2 853 (b)(c) Actual drilling spoils area 0.457 m2, 100 m2 used in calculation to ensure 1 person exposed 4-24
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 854 4.5. References 855 4-1 U.S. Nuclear Regulatory Commission Regulatory Guide 1.187 Guidance for 856 Implementation of 10 CFR 50.59 Changes, Tests and Experiments - November 2000 857 4-2 U.S. Nuclear Regulatory Commission Regulatory Guide 1.179, Standard Format and 858 Content of License Termination Plans for Nuclear Power Reactors - January 1999 859 4-3 Zion Station, Defueled Safety Analysis Report (DSAR) - September 2014 860 4-4 Zion Nuclear Power Station, Units 1 and 2 Asset Sale Agreement - December 2007 861 4-5 ZionSolutions Technical Support Document 10-002, Technical Basis for Radiological 862 Limits for Structure/Building Open Air Demolition 863 4-6 U.S. Nuclear Regulatory Commission NUREG-1575, Revision 1, Multi-Agency 864 Radiation Survey and Site Investigation Manual (MARSSIM) - August 2000 865 4-7 U.S. Nuclear Regulatory Commission Docket Number 50-295, Facility Operating 866 License Number DPR-39 (for Unit One) 867 4-8 U.S. Nuclear Regulatory Commission Docket Number 50-304, Facility Operating 868 License Number DPR-48 (for Unit Two) 869 4-9 U.S. Nuclear Regulatory Commission NUREG-1757, Volume 2, Revision 1, 870 Consolidated Decommissioning Guidance - Characterization, Survey, and 871 Determination of Radiological Criteria, Final Report - September 2003 872 4-10 U.S. Nuclear Regulatory Commission, NUREG/BR-0058, Revision 4, Regulatory 873 Analysis Guidelines of the U.S. Nuclear Regulatory Commission - September 2004 874 4-11 U.S. Nuclear Regulatory Commission, NUREG-1496, Volume 2, Generic 875 Environmental Impact Statement in Support of Rulemaking on Radiological Criteria for 876 License Termination of NRC-Licensed Nuclear Facilities - July 1997 877 4-12 U.S. Nuclear Regulatory Commission, NUREG-1530, Reassessment of NRCs Dollar 878 per Person-Rem Conversion Factor Policy - December 1995 879 4-13 ZionSolutions Technical Support Document 14-016, Description of Embedded Pipe, 880 Penetrations, and Buried Pipe to Remain in Zion End State 881 4-134-14 U.S. Nuclear Regulatory Commission, NUREG/CR-5884, Volume 2, Revised 882 Analyses of Decommissioning for the Reference Pressurized Water Reactor Power 883 Station - November, 1995 884 4-144-15 ZionSolutions Technical Support Document 14-013, Zion Auxiliary Building 885 End State Estimated Concrete Volumes, Surface Areas, and Source Terms 4-25
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 886 4-154-16 ZionSolutions Technical Support Document 14-019, Radionuclides of Concern 887 for Soil and Basement Fill Model Source Terms 4-26