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 4-i 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
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-ii 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
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-i LIST OF ACRONYMS AND ABBREVIATIONS 1
AF Area Factor 2
ALARA As Low As Reasonably Achievable 3
AMCG Average Member of the Critical Group 4
BFM Basement Fill Model 5
CFR Code of Federal Regulations 6
CVS Contamination Verification Survey 7
DCGL Derived Concentration Guideline Levels 8
DSAR Defueled Safety Analysis Report 9
EMC Elevated Measurement Comparison 10 FSS Final Status Survey 11 HEPA High Efficiency Particulate Air 12 ISOCS In Situ Object Counting System 13 LLRW Low Level Radioactive Waste 14 LSA Limited Specific Activity 15 LTP License Termination Plan 16 MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual 17 NRC Nuclear Regulatory Commission 18 ODCM Off Site Dose Calculation Manual 19 ROC Radionuclides of Concern 20 RPT Radiation Protection Technician 21 SAFSTOR SAFeSTORage 22 SFP Spent Fuel Pool 23 TEDE Total Effective Dose Equivalent 24 WWTF Waste Water Treatment Facility 25 ZNPS Zion Nuclear Power Station 26 ZSRP Zion Station Restoration Project 27
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-ii 28 Page Intentionally Left Blank 29
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-1
- 4.
SITE REMEDIATION PLAN 30 In accordance with 10 CFR 50.82(a)(9)(ii)(C), the License Termination Plan (LTP) must provide 31 the plans for site remediation. These plans must include the provisions to meet the criteria 32 from Subpart E of 10 CFR 20 before the site may be released for unrestricted use. The two 33 radiological criteria for unrestricted use specified in 10 CFR 20.1402 are: (1) the Total Effective 34 Dose Equivalent (TEDE) from residual radioactivity that is distinguishable from background 35 radiation must not be greater than 25 mrem/yr to the Average Member of the Critical Group 36 (AMCG) and (2) residual radioactivity levels must be As-Low-As-Reasonably-Achievable 37 (ALARA).
38 Decontamination and dismantlement activities will be conducted in accordance with established 39 Radiation Protection, Safety and Waste Management programs which include approved written 40 procedures. These programs and procedures are frequently audited for technical content and 41 compliance. Revisions have, and will continue to be made to these programs and procedures to 42 accommodate the changing work environment inherent to reactor decommissioning and, 43 documented, processed and approved in accordance with existing administrative procedures 44 using 10 CFR 50.59 and Regulatory Guide 1.187, Guidance for Implementation of 45 10 CFR 50.59 Changes, Tests and Experiments (Reference 4-1) as guidance. Consistent with 46 Regulatory Guide 1.179, Standard Format and Contents for License Termination Plans for 47 Nuclear Power Reactors (Reference 4-2), details regarding changes to the Radiation Protection 48 Program to address remediation and decommissioning activities are not provided in this LTP, but 49 periodic updates to the Zion Station Defueled Safety Analysis Report (DSAR) (Reference 4-3) 50 will provide such details.
51 This chapter describes the methods that may be used to remediate contaminated systems, 52 components and structures. The methods for demonstrating compliance with the ALARA 53 criterion in 10 CFR 20.1402 is also described. Note that Chapter 6 provides the methods for 54 demonstrating compliance with the 25 mrem/yr dose criterion. AlsoAlso, note that Chapter 3 55 describes in detail the remaining site remediation and dismantlement activities and the order in 56 which they will occur for each structure, system and/or component.
57 This chapter also provides a summary of the radiation protection methods and control procedures 58 that will be employed during site dismantlement and remediation.
59 4.1.
Remediation Actions and ALARA Evaluations 60 When dismantlement and decontamination actions are completed, residual radioactivity may 61 remain on building surfaces and in site soils at concentrations that correspond to the maximum 62 annual dose criterion of 25 mrem/yr. The remaining residual radioactivity must also satisfy the 63 ALARA criterion, which requires an evaluation as to whether it is feasible to further reduce 64 residual radioactivity to levels below those necessary to meet the dose criterion (i.e., to levels 65 that are ALARA).
66 The ALARA evaluation calculates the concentration at which the averted collective radiation 67 dose, converted into dollars, is equal to the costs of continued remediation (e.g., risk of 68 transportation accidents converted into dollars, worker and public doses associated with the 69 remediation action converted into dollars, and the actual costs to perform the remediation 70
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-2 activity). If this concentration is below the concentrations that correspond to the maximum 71 annual dose criterion, then further reduction of residual radioactivity is justified by ALARA.
72 Regardless of the outcome of the quantified cost/benefit calculation provided in this chapter, the 73 final dose from residual radioactivity is expected to be well below the dose criterion. The 74 majority of the basement surfaces to be backfilled have minimal contamination. In addition, any 75 areas that are identified as potentially containing activity at levels that could exceeding the 76 Derived Concentration Guideline Level (DCGL), as measured during Final Status Survey (FSS) 77 by the In Situ Object Counting System (ISOCS), will be remediated. Industry standard 78 remediation methods have been shown to remove contamination to levels significantly below the 79 target levels, in this case the DCGL, and this result is expected for any remediation. The 80 combination of low contamination levels over the majority of the basement surfaces combined 81 with remediated areas likely containing activity well below the DCGL, ensures that the final 82 dose from residual radioactivity at license termination will be well below the 25 mrem/yr dose 83 criterion. Based on characterization results, there is limited contamination expected in soil, 84 buried pipe or end-state structures, or above grade buildings with a corresponding dose that is 85 also expected to be well below 25 mrem/yr.
86 4.2.
Remediation Actions 87 Remediation actions are performed throughout the decommissioning process and the techniques, 88 methods and technologies are standard to the commercial nuclear industry. All of the 89 remediation actions described may not necessarily be required, but are listed as possible actions 90 that may be taken during the decommissioning of Zion Nuclear Power Station (ZNPS). The 91 appropriate remediation technique(s), method(s) and/or technologies that will be employed is 92 dependent on the physical composition and configuration of the contaminated media requiring 93 remediation. At ZNPS, the principal media that will be subjected to remediation are concrete 94 structural surfaces. Characterization survey results and historical survey data indicate that there 95 is minimal soil contamination and no groundwater contamination identified to date.
96 4.2.1. Structures 97 The general approach to structure remediation at Zion Station Restoration Project (ZSRP) is 98 driven by section 8.5 of Exhibit C, Lease Agreement, Removal of Improvements; Site 99 Restoration integral to the Zion Nuclear Power Station, Units 1 and 2 Asset Sale Agreement 100 (Reference 4-4) which requires the demolition and removal of all on-site buildings, structures, 101 and components to a depth of at least three feet below grade. Consequently, the only structures 102 that will remain at license termination are the concrete walls and floors below 588 foot elevation 103 in the Unit 1 Containment Building, Unit 2 Containment Building, Auxiliary Building, Turbine 104 Building, Fuel Handling Building, Crib House/Forebay, Waste Water Treatment Facility 105 (WWTF), Circulating Water Intake Piping and Circulating Water Discharge Tunnels. All 106 impacted systems, components and structures above the 588 foot elevation will be removed 107 during the decommissioning process and disposed of as a waste stream. The current 108 decommissioning approach for ZSRP also calls for the beneficial reuse of clean concrete from 109 building demolition as clean fill. The only concrete structures that will be considered are those 110 where the probability of the presence of residual contamination is minimal and surveys 111 demonstrate that the concrete is free of plant derived radionuclides and hazardous paint coatings.
112
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-3 The remaining structural surfaces that will remain at ZNPS following the termination of the 113 license are solid concrete structures which will be covered by at least three 3 feet of soil and 114 physically altered to a condition which would not allow the remaining structural surfaces, if 115 excavated, to be realistically occupied. Consequently, the only applicable dose pathway is from 116 the leaching of residual radioactivity concentrations in the concrete to groundwater. The dose 117 model that will be used to calculate and quantify the future dose to groundwater is referred to as 118 the Basement Fill Model (BFM).
119 Scan measurements, static measurements and/or the analysis of volumetric sample(s) of the 120 remaining concrete media will be used to calculate the remaining total concentration of residual 121 activity remaining in the subsurface concrete structures and the corresponding dose to 122 groundwater. The concrete walls and floors of the basements will be remediated to levels that 123 will provide high confidence that FSS measurements with ISOCS will not exceed radionuclide-124 specific DCGLs that represent the annual dose criterion for unrestricted use specified in 125 10 CFR 20.1402. Rather than using an adjusted gross Derived Concentration Guideline Level 126 (DCGL), the concrete walls and floors from the remaining subsurface basements will be 127 remediated to action levels commensurate with volumetric concentration limits that represent the 128 maximum annual dose criterion for unrestricted release specified in 10 CFR 20.1402.
129 Remediation techniques that may be used for the structural surfaces below 588 foot elevation 130 include washing, wiping, pressure washing, vacuuming, scabbling, chipping, and sponge or 131 abrasive blasting. Cost estimates for these techniques also include the amount of water 132 generated and the cost to process, package and ship this waste. Concrete removal may include 133 using machines with hydraulic-assisted, remote-operated, articulating tools. These machines 134 have the ability to exchange scabbling, shear, chisel and other tool heads.
135 4.2.1.1.
Scabbling and Shaving 136 The principal remediation method expected to be used for removing contaminants from concrete 137 surfaces is scabbling and shaving. Scabbling entails the removal of concrete from a surface by 138 the high-velocity impact of a tool with the concrete surface which transforms the solid surface to 139 a volumetric particulate which can be removed. One method of scabbling is a surface removal 140 process that uses pneumatically operated air pistons with tungsten-carbide tips that fracture the 141 concrete surface to a nominal depth of 0.125 inches at a nominal rate of about 130 ft2 or 142 12.07 m2 per hour. The scabbling pistons (feet) are contained in a close-capture enclosure that is 143 connected by hoses to a sealed vacuum and collector system. Shaving uses a series of diamond 144 cutting wheels on a spindle, and performs at similar rates to scabbling. The wheels are also 145 contained in a close capture enclosure similar to scabbling equipment. The fractured media and 146 dusts from both methods are deposited into a sealed removable container. The exhaust air passes 147 through both roughing and absolute High Efficiency Particulate Air (HEPA) filtration devices.
148 Dust and debris generated through these remediation processes is collected and controlled during 149 the operation.
150 4.2.1.2.
Needle Guns 151 A second method of scabbling is accomplished using needle guns. The needle gun is a 152 pneumatic air-operated tool containing a series of tungsten-carbide or hardened steel rods 153 enclosed in housing. The rods are connected to an air-driven piston to abrade and fracture the 154
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-4 media surface. The media removal depth is a function of the residence time of the rods over the 155 surface. Typically, one to two millimeters are removed per pass. Generated debris collection, 156 transport and dust control are accomplished in the same manner as other scabbling methods. Use 157 of needle guns for removal and chipping of media is usually reserved for areas not accessible to 158 normal scabbling operations. These include, but are not limited to, inside corners, cracks, joints 159 and crevices. Needle gunning techniques can also be applied to painted and oxidized surfaces.
160 4.2.1.3.
Chipping 161 Chipping includes the use of pneumatically operated chisels and similar tools coupled to 162 vacuum-assisted collection devices. Chipping activities are usually reserved for cracks and 163 crevices. This action is also a form of scabbling.
164 4.2.1.4.
Sponge and Abrasive Blasting 165 Sponge and abrasive blasting are similar techniques that use media or materials coated with 166 abrasive compounds such as silica sands, garnet, aluminum oxide, and walnut hulls. Sponge 167 blasting is less aggressive, incorporating a foam media that, upon impact and compression, 168 absorbs contaminants. The medium is collected by vacuum and the contaminants are washed 169 from the medium so the medium may be reused. Abrasive blasting is more aggressive than 170 sponge blasting but less aggressive than scabbling. Both operations use intermediate air 171 pressures. Sponge and abrasive blasting are intended for the removal of surface films and paints.
172 4.2.1.5.
Pressure Washing 173 Pressure washing uses a nozzle of intermediate water pressure to direct a jet of pressurized water 174 that removes superficial materials from the suspect surface. A header may be used to minimize 175 over-spray. A wet vacuum system is used to suction the potentially contaminated water into 176 containers for filtration or processing.
177 4.2.1.6.
Washing and Wiping 178 Washing and wiping decontamination techniques are actions that are typically performed during 179 the course of remediation activities for housekeeping and to minimize the spread of loose surface 180 contamination. ZSRP will implement good housekeeping throughout decommissioning to 181 ensure ALARA, to It is not anticipated that this remediation approach will be employed at ZSRP 182 to reduce the residual activity in structural surfaces for the purpose of meeting the 25 mrem/yr 183 dose criterion but rather, to comply with the open air demolition criteria in ZionSolutions 184 TSD 10-002, Technical Basis for Radiological Limits for Structure/Building Open Air 185 Demolition (Reference 4-5) and, to ensure that loose surface contamination is removed prior to 186 evaluating the surface for acceptable concentrations of residual activity.
187 Washing and wiping techniques are actions that are normally performed during the course of 188 remediation activities and will not always be evaluated as a separate ALARA action. When 189 washing and wiping techniques are used as the sole means to reduce residual contamination 190 below DCGL levels, ALARA evaluations will be performed. Washing and wiping techniques 191 used as housekeeping or good practice measures will not be evaluated.
192
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-5 4.2.1.7.
High-Pressure Water Blasting 193 Most contaminated piping will be removed and disposed of as radioactive waste. Any pipe 194 systems or sections of pipe systems that reside below the 588 foot elevation that will be 195 abandoned in place will be inspected and surveyed as described in Chapter 5. If radiological 196 conditions inside the pipe are in excess of the release criteria, then in situ remediation will be 197 performed. One method that may be used to remediate the pipe interior surfaces is high pressure 198 water blasting. A High-Pressure Liquid-Jetting System has a high pressure water pump capable 199 of producing a water pressure of 10,000 psi to 20,000 psi at an actual flow rate that ranges from 200 44 gallons per minute at 10,000 psi to 23 gallons per minute at 20,000 psi. A rotating jet-mole 201 tip is used for 360 degree coverage of pipe interiors. The jet-mole is attached to a lance and 202 high-pressure hose. The lance is manually advanced through the interior of the pipe. As the 203 lance is advanced, the high-pressure water abrades the interior surface of the pipe, removing the 204 corrosive layer, internal debris and radiological contamination. The waste water containing the 205 removed contamination is then collected and stored for processing as liquid radiological waste.
206 4.2.1.8.
Grit Blasting 207 Another approach that may be used to remediate the surfaces of pipe interior surfaces is grit 208 blasting. Grit blasting uses grit media such as garnet or sand under intermediate air pressure 209 directed through a nozzle that is pulled through the closed piping at a fixed rate. The grit 210 blasting action removes the interior surface layer of the piping. A HEPA vacuum system 211 maintains the sections being cleaned under negative pressure and collects the media for reuse or 212 disposal. The final system pass is performed with clean grit to remove any residual 213 contamination.
214 4.2.1.9.
Removal of Activated/Contaminated Concrete 215 As previously stated, the principal means of remediating concrete surfaces is scabbling/shaving.
216 If the concrete structure is designated for complete removal, such as interior concrete walls or the 217 Bio-Shield, the primary method that will be used to completely remove the concrete is through 218 large scale demolition using hydraulic-operated crushing shears and jack-hammers fitted to large 219 tracked excavators. Concrete structures will be fractured and crushed by these tools. As the 220 concrete is reduced to rubble, the embedded rebar will be exposed and segregated from the 221 concrete rubble. In situations where a more surgical removal is required, activated and/or 222 contaminated concrete removal may be accomplished using a machine mounted, remote-223 operated articulating arm with interchangeable tooling heads. As concrete is fractured and rebar 224 exposed, the metal is cut using flame cutting equipment. The concrete rubble and exposed rebar 225 is collected and transferred into containers for later disposal in both techniques. Dusts, fumes 226 and generated debris are locally collected and as necessary, controlled using temporary 227 enclosures coupled with close-capture HEPA systems or controlled water misting systems. Bulk 228 concrete such as floors and walls may be removed as intact sections after sawing with blades, 229 wires or other cutting methods.
230
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-6 4.2.1.10.
Additional Remedial Actions 231 Mechanical abrasive equipment, such as hones, may be used to remove contamination from the 232 surfaces of embedded/buried piping. Chemical removal means may be used, as appropriate, for 233 the removal of certain contaminants.
234 4.2.2. Soil 235 The surface and subsurface soil DCGLw that will be used to demonstrate compliance with the 236 dose-based criteria of 10 CFR 20, Subpart E for the unrestricted release of open land survey units 237 are provided in Tables 5-4 and 5-5 of Chapter 5. Section 2.5.1.1 of NUREG-1575, Multi-238 Agency Radiation Survey and Site Investigation Manual (MARSSIM) (Reference 4-6) 239 addresses the concern for the presence of small areas of elevated radioactivity. A simple 240 comparison to an investigation level is used to assess the dose impact of potential elevated areas.
241 This is referred to as the Elevated Measurement Comparison (EMC). The investigation level for 242 this comparison is the DCGLEMC, which is the DCGLw modified by an Area Factor (AF) to 243 account for the small area of the elevated radioactivity. Any radiological contamination in soils 244 identified in concentrations greater than the DCGLEMC will be removed and disposed of as 245 radioactive waste.
246 The site characterization process has established the location and extent of soil contamination at 247 ZNPS. Characterization survey results and historical survey data indicate that there is minimal 248 residual radioactivity in soil and no groundwater contamination identified to date. As needed, 249 additional investigations will be performed to ensure that any changing soil radiological 250 contamination profile during the remediation actions is adequately identified and addressed.
251 Chapter 5 discusses soil sampling and survey methods.
252 Soil remediation equipment will include, but not be limited to, shovels, back hoe and track hoe 253 excavators. Other equipment including soil dredges and vacuum trucks may also be used. As 254 practical, when the remediation depth approaches the soil interface region between unacceptable 255 and acceptable contamination, a squared edge excavator bucket design or similar technique may 256 be used. This simple methodology minimizes the mixing of contaminated soils with acceptable 257 lower soil layers as would occur with a toothed excavator bucket.
258 Remediation of soils will be performed using established excavation safety and environmental 259 control procedures. Operational constraints and dust control will be addressed in site excavation 260 and soil control procedures. In addition, work package instructions for remediation of soil may 261 include additional constraints and mitigation or control methods to ensure adequate erosion, 262 sediment, and air emission controls during soil remediation.
263 4.3.
Remediation Activities Impact on the Radiation Protection Program 264 The Radiation Protection Program approved for decommissioning at ZSRP is similar to the 265 regulatory approved program that was implemented during commercial power operation and the 266 subsequent SAFSTOR period. During these periods, in a manner similar to remediation 267 activities during decommissioning, contaminated structures, systems and components were 268 decontaminated in order to perform maintenance or repair actions.
269 The current approved Radiation Protection Program at ZSRP is adequate to comply with all 270 federal and state regulatory requirements for the protection of occupational personnel from 271
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-7 radiological hazards encountered or expected to be encountered during the decommissioning of a 272 two unit commercial reactor facility. In addition, the program ensures the protection of the 273 public from radiological hazards and ensures occupational, effluent and environmental dose from 274 exposure to radioactive materials is, and remains ALARA. To ensure that adequate and proper 275 engineering controls and hazard mitigation techniques are employed, work control programs and 276 procedural requirements allow radiation protection personnel to integrate radiation protection 277 and radiological hazard mitigation measures directly into the work planning and scheduling 278 process. Consequently, the necessary radiological controls are correctly implemented to 279 accommodate each remediation technology as appropriate.
280 The spread of loose surface contamination is mitigated by the routine remediation of work areas 281 by washing and wiping. Water washing with a detergent is effective in reducing low levels of 282 loose surface contamination over large surface areas. Wiping with detergent soaked or oil-283 impregnated media is an effective technique to reduce loose surface contamination on small 284 items, overhead spaces and small hand tools. These same techniques are also effective in 285 reducing low levels of surface contamination on structural surfaces.
286 For intermediate levels of surface contamination, more aggressive methods such as pressure 287 washing, high-pressure water blasting and grit blasting may be more appropriate. Pipes, surfaces 288 and drain lines can be cleaned and hot spots removed using these techniques and technologies.
289 Small tools, hoses and cables can also be pressure washed in a containment to reduce 290 contamination levels. A paint coating may be applied after surface cleaning to prevent surface 291 contamination from drying out and becoming airborne.
292 To mitigate high levels of fixed surface contamination embedded in concrete, scabbling or other 293 surface removal techniques may be appropriate. A combination of mechanical and flame cutting 294 will be used to section the reactor vessel and its internals.
295 The Radiation Protection Program approved for decommissioning is similar to the program in 296 place during commercial power operation. During power operations, contaminated structures, 297 systems and components were decontaminated in order to perform maintenance or repair actions.
298 These techniques are the same or similar to the radiological controls implemented at ZSRP for 299 the decommissioning to reduce personnel exposure to radiation and contamination and to prevent 300 the spread of contamination from established contaminated areas. Concrete cutting or surface 301 scabbling, mechanical cutting, abrasive water jet cutting, hydrolazing and grit blasting has been 302 used at ZNPS in the past during operations. The current Radiation Protection Program provides 303 adequate controls for these actions.
304 Decommissioning does not present any new challenge to the Radiation Protection Program 305 above those encountered during normal plant operation and refueling. Decommissioning 306 planning allows radiation protection personnel to focus on each area of the site and plan each 307 activity well before execution of the remediation technique.
308 The decommissioning organization is experienced in and capable of applying these remediation 309 techniques on contaminated systems, structures or components during decommissioning. The 310 Radiation Protection Program is adequate to safely control the radiological aspects of this work.
311 Because the activities expected during decommissioning are the same or similar to those 312 encountered during operations, as described above, the approval of any changes to the existing 313 approved Radiation Protection Program as described in the Nuclear Regulatory Commission 314
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-8 (NRC) Docket Number 50-295, Facility Operating License Number DPR-39 (for Unit One) 315 (Reference 4-7), NRC Docket Number 50-304, Facility Operating License Number DPR-48 316 (for Unit Two) (Reference 4-8) is not requested in this LTP.
317 4.4.
ALARA Evaluation 318 Guidance for conducting ALARA analyses is provided in Appendix N of NUREG-1757, 319 Volume 2, Revision 1, Consolidated Decommissioning Guidance - Characterization, Survey, 320 and Determination of Radiological Criteria, Final Report (Reference 4-9), which describes 321 acceptable methods for determining when further reduction of residual radioactivity is required 322 to concentrations below the levels necessary to satisfy the 25 mrem/yr dose criterion.
323 The surface and subsurface soil DCGLw that will be used to demonstrate compliance with the 324 25 mrem/yr dose criterion are provided in Tables 5-4 and 5-5 of Chapter 5. Characterization 325 survey results and historical survey data indicate that there is minimal residual radioactivity in 326 soil at ZNPS. Throughout the course of the decommissioning and through to site closure, ZSRP 327 will continue to survey and characterize soils as they are exposed by excavation during building 328 demolition or made accessible by the removal of structures or components. If residual 329 radioactivity is discovered at concentrations greater than the DCGLEMC in surface or subsurface 330 soils, ZSRP will excavate, package and dispose of the soil as Low-Level Radioactive Waste 331 (LLRW).
332 Section N.1.5 of NUREG-1757 states that For residual radioactivity in soil at sites that may 333 have unrestricted release, generic analyses show that shipping soil to a low-level waste disposal 334 facility is unlikely to be cost effective for unrestricted release, largely because of the high costs 335 of waste disposal. Therefore shipping soil to a low-level waste disposal facility generally does 336 not have to be evaluated for unrestricted release. To illustrate that this is a reasonable 337 approach and applicable to ZSRP, a simple ALARA analysis for the excavation and disposal of 338 soils as low-level radioactive waste is provided in section 4.4.1.
339 For the subsurface structures that will remain at license termination, the ALARA analysis will 340 determine whether further concrete remediation is necessary by comparing the desired beneficial 341 effects to the undesired costs. Benefits are the averted collective radiation dose (converted into 342 dollars) following the removal of radioactivity. The costs of remediation include transportation 343 accidents, worker and public dose associated with remedial action, and the actual costs to 344 perform the remediation (converted into dollars). If the costs exceed the benefits, then the dose 345 reduction achieved by further remediation is not ALARA.
346 The ALARA criterion specified in 10 CFR 20.1402 is not met by solely performing remediation.
347 The ALARA analysis is a planning tool to justify that further remediation is not necessary.
348 When remediation is performed, there is no need to analyze whether the action was necessary to 349 meet the ALARA requirement. The remediation required to meet the open air demolition criteria 350 specified in TSD 10-002, including cleaning loose surface contamination to concentrations 351 below 1,000 dpm/100cm2 and the remediation of concrete surfaces to meet the 2 mR/h exposure 352 rate criteria, will be performed regardless of the outcome of the ALARA evaluation.
353 Consequently, this is an example of when a remediation action is not required to be evaluated for 354 ALARA.
355
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-9 The methods and results of the ALARA evaluation for concrete remediation in structures below 356 588 foot elevation is provided in section 4.4.2.
357 4.4.1. ALARA Analysis of Soil Remediation 358 In order to determine if additional remedial action is warranted by ALARA analysis, the desired 359 beneficial effects (benefits) and the undesirable effects (costs) must be calculated. If the benefits 360 from remedial action will be greater than the costs, then the remedial action is warranted and 361 should be performed. However, if the costs exceed the benefit, then the remedial action is 362 considered to be not ALARA and should not be performed.
363 Based upon a simple ALARA analysis, the only benefit of reducing residual radioactivity in soil 364 is the monetary value of the collective averted dose to future occupants of the site. For soils, the 365 averted dose is based upon the resident farmer scenario.
366 4.4.1.1.
Calculation of Benefits 367 The benefit from collective averted dose (BAD) is calculated by determining the present worth of 368 future collective averted dose and multiplying by a factor to convert the dose to a monetary 369 value. In accordance with Appendix N of NUREG-1757, the equation is as follows; 370 Equation 4-1 371
= $2,000 x ()
372 where; 373 BAD
= benefit from an averted dose for a remediation action, in 374 US dollars, 375
$2,000
= value in dollars of a person-rem averted and, 376 PW(ADCollective)
= present worth of a future collective averted dose.
377 The present worth of future collective averted dose PW(ADCollective) is then expressed in 378 accordance with the following equation; 379 Equation 4-2 380
() = ()()(0.025)()
1 (+)
+
381 where; 382 PD
=
population density for the critical group scenario in 383 people/m2, 384 A
=
area being evaluated in square meters (m2),
385 0.025
=
annual dose to an AMCG from residual radioactivity at the 386 DCGLw concentration in rem/yr, 387 F
=
effectiveness, or fraction of the residual radioactivity 388 removed by the remediation action, 389
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-10 Conc
=
average concentration of residual radioactivity in the area 390 being evaluated in units of activity per unit volume (pCi/g),
391 DCGLw
=
derived concentration equivalent to the average 392 concentration of residual radioactivity that would give a 393 dose of 25 mrem/yr to the AMCG (pCi/g),
394 r
=
monetary discount rate in units per year (yr-1),
395
=
radiological decay constant for the radionuclide in units per 396 year and, 397 N
=
number of years over which the collective dose will be 398 calculated.
399 4.4.1.2.
ALARA Analysis Parameters 400 In accordance with Table N.2 of Appendix N of NUREG-1757, the acceptable and relevant 401 parameters for use in performing ALARA analysis are as follows; 402
- Dollars per person-Rem rem - $2,000.00/person-rem (per NUREG/BR-0058, Regulatory 403 Analysis Guidelines of the U.S. Nuclear Regulatory Commission [Reference 4-10])
404
- Population density (PD) for the critical group (persons/m2) - 0.0004 person/m2 for land (per 405 NUREG-1496, Final Generic Environmental Impact Statement in Support of Rulemaking 406 on Radiological Criteria for License Termination of NRC-Licensed Nuclear Facilities, 407 Volume 2, [Reference 4-11] Appendix B, Table A.1) 408
- Monetary discount rate (r) - 0.00 yr-1 for soilMonetary discount rate (r) - 0.03 yr-1 for soil 409 (per NUREG/BR-0058) 410 (Note:; This variable was established at 0.03 yr-1 for soil in Table N.2 of Appendix N of 411 NUREG-1757. The monetary discount for the ALARA analysis was removed from the 412 equation through Federal Register Notice 72 FR 46102 - August 16, 2007. Consequently, 413 the r variable has been conservatively set at 0.00 yr-1 for soil, i.e., no monetary discount for 414 soils as well as basements.)
415
- Area (A) used to calculate the population density (m2) - 10,000 m2 (size of reference area 416 that was evaluated) 417
- Number of years (N) over which the collective averted dose is calculated (yr) - 1,000 yrs (per 418 NUREG-1496, Volume 2, Appendix B, Table A.1) 419 4.4.1.3.
Calculation of Costs 420 The total cost, (CostT) which is balanced against the benefits; has several components and may 421 be evaluated according to Equation N-3 of NUREG-1757, Appendix N below:
422 Equation 4-3 423
=+ + + + +
424 where:
425
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-11 CostR
=
monetary cost of the remediation action (including 426 mobilization costs);
427 CostWD
=
monetary cost for transport and disposal of the waste 428 generated by the action; 429 CostACC
=
monetary cost of worker accidents during the remediation 430 action; 431 CostTF
=
monetary cost of traffic fatalities during transportation of 432 the waste; 433 CostWDose
=
monetary cost of traffic fatalities during transportation of 434 the waste; 435 CostPDose
=
monetary cost of dose to the public from excavation, 436 transport and disposal of the waste; 437 4.4.1.4.
Calculation of Total Cost for Soil Remediation by Excavation and Disposal 438 For the analysis of soil excavation and disposal as low-level radioactive waste, the variables for 439 CostR, CostACC, CostWDose and CostPDose were not calculated for this evaluation based upon their 440 anticipated unlikely impact on the total cost (CostT). This is consistent with the guidance 441 provided in NUREG-1757 which states that if one or two of the costs can be shown to exceed the 442 benefit, then the remediation cost is shown to be unnecessary without calculating all of the costs.
443 4.4.1.4.1.
Transport and Disposal of the Waste (CostWD) 444 The cost of waste transport and disposal (CostWD) was calculated using Equation N-4 of 445 NUREG-1757, Appendix N which is expressed as follows:
446 Equation 4-4 447
=x 448 where:
449 VA
=
volume of waste produced, remediated in units of m3; 450 CostV
=
cost of waste disposal per unit volume, including 451 transportation cost, in units of $/m3.
452 Disposal costs for generated waste were based on an average total disposal cost of $2,500/m3.
453 This average cost includes packaging, transportation and disposal fees. The transportation 454 component of this average cost is based on the average transportation cost of using either rail or 455 highway hauling from the Zion site to Clive, Utah (EnergySolutions radioactive waste disposal 456 facility). The details of the average total disposal cost (CostV) of $2,500/m3 of waste are 457 considered proprietary values defined by negotiated contract.
458 The volume of waste produced by remediation (VA) assumes that the reference area of 10,000 m2 459 (A) is remediated to a depth of 0.15 meters. This results in a value for waste volume (VA) of 460 1,500 m3, which produces a value for CostWD of $3,750,000.00.
461
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-12 4.4.1.4.2.
Transportation Risks (CostTF) 462 The cost of traffic fatalities incurred during the transportation of waste (CostTF) was calculated 463 using Equation N-6 of NUREG-1757, Appendix N which is expressed as follows:
464 Equation 4-5 465
=$3,000,000 x
x x 466 where:
467
$3,000,000
=
monetary value of a fatality equivalent to $2000/person-468 rem (NUREG-1530 Reassessment of NRCs Dollar per 469 Person-Rem Conversion Factor Policy [Reference 4-12])
470 VA
=
volume of waste produced in units of m3; 471 VSHIP
=
volume of a truck shipment in m3; 472 FT
=
fatality rate per truck-kilometer traveled in units of 473 fatalities/truck-km; 474 DT
=
distance traveled in km.
475 For this evaluation, the waste volume (VA) is assumed to be 1,500 m3 and the haul volume of an 476 overland truck shipment per NUREG-1757 is assumed to be 13.6 m3 (VSHIP).
477 In accordance with NUREG-1496, Appendix B, Table A.1, a value of 3.8 E-08/hr was used for 478 FT.
479 The Clive, Utah round trip distance from the Zion site by highway is 1,463 miles (2,355 km).
480 The distance for rail shipments is further than that for highway shipments because of the route 481 rail shipments must follow, however the difference as it pertains to the calculation is 482 insignificant. The highway shipment distance of 2,355 km (DT) was used for the calculation of 483 CostTF. For this evaluation, the value for the CostTF variable is $29,610.66.
484 4.4.1.4.3.
Total Cost (CostT) 485 The total cost, (CostT) assumed for this evaluation is $3,779,610.66.
486 4.4.1.5.
Residual Radioactivity in Soils that are ALARA 487 Determination of residual radioactivity in soils that are ALARA is the concentration at which 488 benefit equals or exceeds the costs of removal and waste disposal. When the total cost (CostT) is 489 set equal to the dose averted, the ratio of the concentration to the DCGLw is calculated as 490 follows; 491 Equation 4-6 492
=
()(+ )
($2,000)()(0.025)()()(1 (+))
493 Assuming the following values for the remaining variables; 494
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-13
- the default parameter values from section 4.4.1.2, 495
- a value of one for remediation effectiveness (F), assuming all residual radioactivity is 496 removed during the excavation, 497
- a surface soil DCGLw of 1514.18 pCi/g for Cs-137 from Table 5-4 of Chapter 5, 498 Equation 4-7 499
=
($3,779,610.66) 0.030 + 0.693 30.17
($2,000)(0.0004)(0.025)(1)(10,000) 1 0.030+0.693 30.171,000 500 the ratio of the concentration to the DCGLw when the total cost (CostT) is equal to the dose 501 averted is 1,001.03434.08.
502 Assuming a concentration set at 50% of the DCGLw (based on the investigation level for a 503 Class 3 area), the present worth of future collective averted dose PW(ADCollective) can be 504 calculated as follows; 505 Equation 4-8 506
()
507
= (0.0004)(10,000)(0.025)(1) 7.09 15.814.21 0.030+0.693 30.17(1,000) 0.030 + 0.693 30.17 508 resulting in a value for PW(ADCollective) of 0.942.18 person rems. The benefit from collective 509 averted dose (BAD) is then calculated as follows; 510 Equation 4-9 511
= $2,000 x 0.942.18 = $14,880353.0054 512 This simple analysis confirms the statement in section N.1.5 of NUREG-1757 that the cost of 513 disposing excavated soil as low-level radioactive waste is clearly greater than the benefit of 514 removing and disposing of soil with residual radioactivity concentrations less than the dose 515 criterion. Since the cost is greater than the benefit, it is not ALARA to excavate and dispose of 516 soils with residual radioactivity concentrations below the DCGLw.
517 4.4.2. ALARA Analysis for Remediation of Basement Structures 518 With the exception of some penetrations, embedded and buried piping, all contaminated and 519 non-contaminated systems will be disassembled, removed, packaged and shipped off-site as a 520 waste stream commodity. The list of penetrations and embedded piping to remain is provided in 521 ZionSolutions TSD 14-016,14-016, Description of Embedded Pipe, Penetrations, and Buried 522 Pipe to Remain in Zion End State (Reference 4-13). Once commodity removal is complete, 523 structural surfaces will be remediated as necessary to meet the open air demolition criteria 524 specified in TSD 10-002. These criteria provide the removable contamination levels and contact 525 exposure rates that will allow structures to be safely demolished without containment. Prior to 526 demolition, a contamination verification survey (CVS) will be performed to identify areas 527
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-14 requiring remediation to meet the open-air demolition limits. The CVS will also be used to 528 identify areas on surfaces to remain at license termination (i.e., at least three feet below grade) 529 that could potentially result in a FSS measurement (using ISOCS) to exceed the Basement 530 DCGLs (DCGLB) listed in LTP Chapter 5, Table 5-3. The dose rate target for this objective will 531 be lower than that required for open-air demolition. Identified areas will be remediated to 532 provide high confidence that no FSS ISOCS measurement will exceed the DCGLB. These 533 conditions or indicators are designations used to characterize the acceptable removable 534 contamination and contact exposure rates that will safely allow structures to be demolished 535 without containment. The limits are based upon re-suspension factors and ground level release 536 and dispersion models. Public dose is calculated at the site boundary using Off Site Dose 537 Calculation Manual (ODCM) methodologies for a ground level airborne radioactivity release.
538 The objectives of the open air demolition limits are:
539 To ensure ground level airborne radioactivity levels remain ALARA and within regulatory limits 540 (note that in this case, ALARA refers to operational ALARA and not 10 CFR 20.1402 541 compliance).
542 To ensure demolition liquid concentrations remain at levels which can be collected, processed 543 and released using plant water treatment systems and discharge points.
544 To minimize the spread of contamination within the site boundary such that there is not 545 significant effect on groundwater or the scope of soil remediation required for License 546 Termination.
547 To ensure open air demolition activities can be conducted using conventional demolition 548 techniques with minimal radiological restrictions or controls.
549 Based upon the calculations, comparison and conclusions documented in TSD 10-002, the 550 following open air demolition limits will be implemented:
551 Less than 2 mR/hr beta-gamma total contamination on contact with structural concrete.
552 Less than 1,000 dpm/100cm2 beta-gamma loose surface contamination.
553 All structural surfaces will be remediated to the open air demolition limits prior to demolition.
554 Confirmatory surveys will be performed using approved procedures following remediation and 555 prior to demolition to ensure that contamination levels are at or below the open are demolition 556 criteria. It is expected that remediation to open air demolition criteria will reduce the structure 557 source terms to level below that corresponding to 25 mrem/yr. If not, additional remediation will 558 be performed to meet the 25 mrem/yr dose limit. Once remediation is complete structural 559 surfaces located above the 588 foot elevation and non-load-bearing interior concrete walls below 560 the 588 foot elevation will be demolished, reduced in size, packaged and shipped off-site to a 561 licensed disposal facility.
562 All concrete inside the liner above the 541565 foot elevation will be removed from the interiors 563 of both Containment Buildings prior to demolition. This includes all activated and contaminated 564 concrete. Only the concrete below the 541565 foot elevation in the In-core Instrument Shaft 565 leading to and including the area under vessel (or Under-Vessel area) will remain. The source 566 term in the Containment Basements remaining after demolition will be consist of the concrete in 567 the Under-Vessel area(s) and low levels of surface contamination on the exposed liner surfaces.
568 There is currently minimal contamination in the Turbine Building, Crib House/Forebay, and 569
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-15 Circulating Water Piping at levels that are expected to be well below the open air demolition 570 criteria and below the DCGLB listed in LTP Chapter 5, Table 5-3.contamination levels 571 corresponding to 25 mrem/yr dose limit in the BFM (see Chapter 6 for a detailed description of 572 the BFM). The only portion of the Fuel Handling Building Basement that will remain following 573 building demolition is the lower 13 foot (~4 m) concrete bottom of the Spent Fuel Pool (SFP) 574 and the Transfer Canal, which is located at the 575 foot elevation. The steel liner will be 575 removed from both the SFP and the Transfer Canal. After the liner is removed and the 576 underlying concrete exposed, additional continuing characterization surveys will be performed to 577 assess the radiological condition of the underlying concrete pad and remaining pool walls.
578 Continuing characterization will consist of scanning of the exposed concrete surfaces and the 579 acquisition of concrete core sample(s) at the location of highest activity. Contamination is 580 expected below the liner but an estimate of levels cannot be made until characterization is 581 completed.
582 In summary, the vast majority of residual radioactivity remaining in the structures after the open 583 air demolition criteria is met and after the majority ofall concrete is removed from the 584 Containment Building basements will be located in the 542 foot elevation floor of the Auxiliary 585 Building. Therefore, the ALARA assessment for the remediation of basement structures will 586 focus on the 542 foot elevation floor of the Auxiliary Building as this is the location were the 587 greatest benefit of concrete remediation could be achieved. An ALARA assessment of the 588 542 foot elevation floor of the Auxiliary Building will bound ALARA assessments for the other 589 buildings which would use the same methods (and cost estimate) but remove less contamination.
590 If continuing characterization indicates significant concentrations of residual radioactivity 591 remaining in other end-state structures (e.g., Under-Vessel area, SFP/Transfer Canal, Auxiliary 592 Building embedded drains), then ZSRP will perform and document a separate ALARA analysis 593 or, provide evidence that the ALARA analysis of the 542 foot floor of the Auxiliary Building is 594 still bounding.
595 The Auxiliary Building basement concrete at the 542 foot elevation is volumetrically 596 contaminated. A total of twenty (20) concrete core samples were collected in the Auxiliary 597 Building during characterization. The sample analysis of these concrete core samples indicates 598 that the majority of the radionuclide inventory resides within the first 1/2-inch of concrete.
599 However, several core samples show detectable Cs-137 and Co-60 at depths in excess of six 600 inches.
601 4.4.2.1.
ALARA Analysis Equation for Remediation of Basement Structures 602 For the ALARA analysis for the remediation of basement structures, the equation from section 603 4.4.1.5 for the ratio of the concentration to the DCGLw when the total cost (CostT) is set equal to 604 the dose averted is modified as follows. The BFM DFsDCGLs for concrete are expressed in 605 units of mrem/yr per mCi total activitypCi/m2. The denominator must be summed and the 606 individual dose contribution normalized to account for the multiple detectable radionuclides that 607 are present in the radionuclide distribution for the Auxiliary Building. The equation from 608 NUREG-1757 therefore becomes:
609
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-16 Equation 4-10 610
=
()(+ )
($2,000) ()()(0.025)()()(1 (+))
611 where:
612 fi
=
the normalized product of the Basement Inventory 613 Levelsradionuclide fraction for the Auxiliary Building for 614 each individual Radionuclides of Concern (ROC) (from 615 Chapter 5, Table 5-92) normalized to one 616 DOSEAMCG
=
averted dose to the AMCG (rem).
617 The total cost for the remedial action when divided by the total benefit of averted dose 618 determines the cost effectiveness of the remedial action. Values greater than unity demonstrate 619 that no further remediation is necessary beyond that required to meet the 25 mrem/yr dose 620 criterion and are ALARA. Values less than one provide the fraction of the 25 mrem/yr dose 621 criterion where it is necessary to remediate to achieve ALARA.
622 4.4.2.2.
Remedial Action Costs 623 The only structures that will remain as potential candidate surfaces for remediation are the 624 concrete walls and floors from the Auxiliary Building, the Under-Vessel area(s), Turbine 625 Building, Crib House/Forebay, WWTF, the lower 13 foot concrete bottom of the SFP, the 626 Circulating Water Intake Piping and Circulating Water Discharge Tunnels. With the exception 627 of some sections of buried and embedded pipe, all impacted systems, components as well as all 628 structures above the 588 foot elevation will be removed during the decommissioning process and 629 disposed of as a waste stream. The current decommissioning approach for ZSRP also calls for 630 the beneficial reuse of concrete from building demolition as clean fill. As discussed above, the 631 vast majority of contamination to remain after removal of containment concrete will be in the 632 542 foot elevation floor of the Auxiliary Building.
633 Prior to building demolition, all structures will be remediated to meet the open air demolition 634 limits specified in TSD 10-002 and, to provide high confidence that ISOCS measurements taken 635 during FSS will not exceed the DCGLB from Table 5-3. All loose surface contamination greater 636 than 1,000 dpm/100cm2 will be removed. The remediation techniques most likely to be 637 implemented to perform this work are vacuuming, pressure washing and hand-wiping,. In 638 addition, TSD 10-002 calls for structural surfaces that exhibit fixed contamination in excess of 639 2 mR/hr beta-gamma total surface contamination on contact to be remediated. The remediation 640 approach used to accomplish this action will likely be concrete scabbling or concrete shaving.
641 As these efforts will occur prior to evaluating the remaining structural surfaces for acceptable 642 concentrations of residual activity, this remediation action will not be evaluated for ALARA.
643 The remediation action evaluated for the ALARA analysis for the remediation of basement 644 structures is scabbling the concrete surface of the 542 foot elevation floor of the Auxiliary 645 Building. Concrete core samples indicate that the majority of the radionuclide source inventory 646 in the 542 foot elevation concrete floor resides within the first 1/2-inch of concrete. For the 647 purposes of the ALARA evaluation, it is conservatively assumed that 100% of the contamination 648 resides in the first 1/2 inch. In accordance with the guidance in section G.3.1 of NUREG/CR-649
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-17 5884, Revised Analyses of Decommissioning for the Reference Pressurized Water Reactor 650 Power Station Volume 2 (Reference 4-1314), one pass of scabbling is assumed to remove 651 0.125 inches (0.635 cm) of concrete. In accordance with ZionSolutions TSD 14-013, Zion 652 Auxiliary Building End State Estimated Concrete Volumes, Surface Areas, and Source Terms 653 (Reference 4-1415), the 542 foot elevation floor of the Auxiliary Building has a surface area of 654 2,543 m2. This is the surface area which will be evaluated for the remediation cost 655 determination.
656 4.4.2.2.1.
Remediation Activity Rates 657 The remediation activity rates that were used for this evaluation were based on previous 658 experience, from published literature, or from groups or vendors currently performing these or 659 similar activities. Current project labor costs and past operational experience were also used in 660 developing these rates.
661 In accordance with NUREG/CR-5884, an assumed crew size for performing concrete scabbling 662 or shaving activities is three full-time laborers, a supervisor at a 1/4-time involvement and a 663 Radiation Protection Technician (RPT), also at a 1/4-time involvement. Using the current project 664 labor rates for these positions of $66.78 per hour for a laborer, $90.00 per hour for a supervisor 665 and $55.59 per hour for a RPT, the hourly unit rate that will be used for the evaluation is 666
$236.74.
667 Using the guidance found in NUREG/CR-5884 it is assumed that the concrete scabbling or 668 shaving activity will remove approximately 0.125 inches of concrete per pass and the effective 669 nominal removal rate is approximately 12.07 m2 per hour. The ALARA evaluation assumes that 670 100% of the radioactive contamination resides within the first 1/2 inch. Consequently, removing 671 1/2 inch of concrete over an assumed reference area of 2,543 m2, scabbling at a nominal rate of 672 12.07 m2 per hour to a depth of 0.125 inch per pass, equates to approximately 836.5 man-hours 673 of work.
674 Also in accordance with NUREG/CR-5884 it is assumed that the actual remediation time in a 675 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 676 preparation, donning and removing protective clothing and work breaks, the total man-hours 677 were increased by a factor of 33% which equates to 1,112 man-hours. In addition, a contingency 678 of 25% was added to the manpower hours. This equates to a total man-hours of 1,390.61 man-679 hours, which is multiplied times the hourly unit rate of $236.74 to equal the labor cost for this 680 evaluation of $329,209.54.
681 4.4.2.2.2.
Equipment Costs 682 Using the guidance found in NUREG/CR-5884, equipment costs are based on the rental of 683 commercially available scabbing equipment, a compressor, a vacuum unit and consumables such 684 as cutting bits, vacuum filters and waste drums for containing waste debris. At 40-hours per 685 work week, 1,391 man-hours equates to approximately 35 work-weeks. This evaluation assumes 686 that two different commercially available concrete removal units will be procured, the Pentek 687 Squirrel Scabbler & Vacuum System with a nominal rental rate of $685.00 per week and a 688 Pentek Moose Scabbler & Vacuum System with a nominal rental rate of $950.00 per week. The 689 compressor required for pneumatic equipment operation can be rented at a nominal rate of 690
$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 691
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-18 operation, for an equivalent cost of about $13.00 per hour of operation. Additional costs include 692 filter replacements at about $2.50 per hour of operation and waste drums for the collected debris.
693 A 55-gallon drum holds approximately 7 ft3 of waste and cost approximately $100.00 per drum.
694 As it is assumed that the scabbing activity will generate approximately 1,132 ft3 (32 m3) of 695 concrete waste, this will require the procurement of approximately 162 drums at a total cost of 696
$16,171.49. The mobilization and demobilization costs associated with procuring this equipment 697 would be approximately $2,200.00 per piece of equipment for a total of approximately 698
$6,600.00. The total equipment costs assumed for this evaluation is approximately $98,975.87.
699 4.4.2.2.3.
Total Remediation Action Cost (CostR) 700 For the evaluation of the remediation activity of concrete scabbling or shaving, the sum of the 701 labor cost of $329,209.54 plus the equipment cost of $98,975.87 results in a total remediation 702 action cost (CostR) for this activity of $428,185.41.
703 4.4.2.3.
Transport and Disposal of the Waste (CostWD) 704 As previously described in section 4.4.1.4.1, the cost of waste transport and disposal (CostWD) is 705 expressed as follows:
706 Equation 4-11 707
=x 708 Disposal costs for generated waste were based on an average total disposal cost of $2,500/m3.
709 This average cost includes packaging, transportation and disposal fees. The transportation 710 component of this average cost is based on the average transportation cost of using either rail or 711 highway hauling from the Zion site to Clive, Utah (EnergySolutions radioactive waste disposal 712 facility). Based upon an assumed waste volume of 32 m3, a value of $80,000.00 is calculated for 713 the CostWD variable.
714 4.4.2.4.
Non-Radiological Risks (CostACC) 715 The cost of non-radiological workplace accidents (CostACC) was calculated using Equation N-5 716 of NUREG-1757, Appendix N which is expressed as follows:
717 Equation 4-12 718
=$3,000,000.00 x x 719 where:
720
$3,000,000
=
monetary value of a fatality equivalent to $2000/person-721 rem (NUREG-1530) 722 FW
=
workplace fatality rate in fatalities/hour worked; 723 TA
=
worker time required for remediation in units of worker-724 hours.
725 In accordance with NUREG-1496, Appendix B, Table A.1, a value of 4.2 E-08/hr was used for 726 FW. For TA, in accordance with NUREG-1757 the same hours that was determined for labor cost 727
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-19 (1,391 man-hours) was used for worker accident cost. Subsequently, a value of $175.27 is 728 calculated for the CostACC variable.
729 4.4.2.5.
Transportation Risks (CostTF) 730 As previously described in section 4.4.1.4.2, the cost of traffic fatalities incurred during the 731 transportation of waste (CostTF) is expressed as follows:
732 Equation 4-13 733
=$3,000,000.00 x
x x 734 For this evaluation, the waste volume (VA) is assumed to be 32 m3 and the haul volume of an 735 overland truck shipment per NUREG-1757 is assumed to be 13.6 m3 (VSHIP).
736 In accordance with NUREG-1496, Volume 2, Appendix B, Table A.1, a value of 3.8 E-08/hr 737 was used for FT.
738 The Clive, Utah round trip distance from the Zion site by highway is 1,463 miles (2,355 km).
739 The distance for rail shipments is further than that for highway shipments because of the route 740 rail shipments must follow, however the difference as it pertains to the calculation is 741 insignificant. The highway shipment distance of 2,355 km (DT) was used for the calculation of 742 CostTF. For this evaluation, the value for the CostTF variable is $631.69.
743 4.4.2.6.
Worker Dose Estimates (CostWDose) 744 The cost of remediation worker dose (CostWDose) was calculated using Equation N-7 of NUREG-745 1757, Appendix N which is expressed as follows:
746 Equation 4-14 747
=$2,000.00 x x 748 where:
749 DR
=
total effective dose equivalent (TEDE) rate to remediation 750 workers in units of Remrem/hr; 751 T
=
time worked (site labor) to remediate the area in units of 752 person-hour.
753 Costs associated with worker dose are a function of the hours worked and the workers radiation 754 exposure for the task. A value of 3 mrem per man-hour was used for DR. This assumes that a 755 majority of the source inventory will be removed prior to performing the concrete scabbling or 756 shaving activity. The time worked to remediate the area in units of person-hour calculated for 757 this activity (T) was 1,391 man-hours. For this evaluation, the value for the CostWDose variable is 758
$8,346.00.
759 4.4.2.7.
Monetary Cost of Dose to the Public (CostPDose) 760 The cost of remediation worker dose (CostPDose) was calculated using Equation N-7 of NUREG-761 1757, Appendix N which is expressed as follows:
762
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-20 Equation 4-15 763
=$2,000.00 x x 764 where:
765 DR
=
total effective dose equivalent (TEDE) rate to public in 766 units of Remrem/hr; 767 T
=
time spent near waste shipments in parking lots in units of 768 person-hour.
769 For this equation, a worst-case value of 0.5 mrem/hr was used for DR. This assumes that the 770 shipment is classified as Limited Specific Activity (LSA) in accordance with 49 CFR 173.427 771 and the package meets the Zion specific administrative limit of 0.5 mrem/hr on the exterior of 772 the shipment. The exposure time (T) used for this calculation is based upon a transit time of 773 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 774 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.
775 4.4.2.8.
Total Cost (CostT) 776 The total cost, (CostT) assumed for this evaluation is $517,407.37 777 4.4.2.9.
Residual Radioactivity in Basement Structures that are ALARA 778 The following parameters were used for performing the ALARA calculation using the equation 779 from NUREG-1757 and presented in section 4.4.2.1:
780
- Population density (PD) for the critical group (persons/m2) - 0.0004 person/m2 for soil (per 781 NUREG-1496, Appendix B, Table A.1) 782
- Fraction of residual radioactivity removed by the remedial action (F) - 1 (Removal of desired 783 concrete volume is assumed 100% effective) 784
- Area (A) used to calculate the population density (m2) -
785 o Groundwater scenario -10,000 m2 (size of resident farmer reference area) 786 o Drilling Spoils scenario - 100 m2 is assumed in order to allow the calculation to generate 787 a population of 1 person exposed to drilling spoils. The actual surface area of the drilling 788 spoils is much smaller at 0.46 m2 (see LTP Chapter 6) 789
- Monetary discount rate (r) - 0.00 yr-1 for soil 790 (Note; This variable was established at 0.03 yr-1 for soil in Table N.2 of Appendix N of 791 NUREG-1757. The monetary discount for the ALARA analysis was removed from the 792 equation through Federal Register Notice 72 FR 46102 - August 16, 2007. Consequently, 793 the r variable has been conservatively set at 0.00 yr-1 for soil, i.e., no monetary discount for 794 soils as well as basements.)Monetary discount rate (r) - 0.03 yr-1 for soils (per NUREG/BR-795 0058) 796
- Number of years (N) over which the collective averted dose is calculated (yr) - 1,000 yrs (per 797 NUREG-1496, Appendix B, Table A.1) 798
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-21 4.4.2.9.1.
Radionuclides Considered for ALARA Analysis 799 The radionuclide mixture for contaminated concrete developed in ZionSolutions TSD 14-019, 800 Radionuclides of Concern for Soil and Basement Fill Model Source Terms (Reference 4-1516) 801 was used for the ALARA analysis. The Basement Inventory LevelsDCGLB for the Auxiliary 802 Building for each individual ROC from Chapter 5, Table 5-9 3 were used for the calculation of fi.
803 DCGLs, in units of pCi/m2 of basement surface area, are presented in Chapter 6, section 6.6.8.1 804 for the Basement Fill Model (BFM) Groundwater and BFM Drilling Spoils scenarios 805 individually and are designated as the DCGLBS (Basement Scenario DCGLs). The 806 DCGLBSBasement Inventory Levels for the Auxiliary Building are reproduced in Table 4-1.
807 The values for half-life, radiological decay constants () and the radionuclide mixture fractions 808 are presented in Table 4-2. The mixture fractions are based on the analysis of the concrete core 809 samples taken on the Auxiliary Building 542 foot elevation and presented in TSD 14-019, 810 Table 17.
811 The ALARA calculation was performed in two parts, the first representing the Groundwater 812 scenario and the second representing the Drilling Spoils scenario. Two dose values were 813 required to accurately calculate the averted dose because the compliance dose is based on the 814 sum of both scenarios. In addition, each scenario is applicable to a different area. The 815 Groundwater dose applies to the full 10,000 m2 site area, the Drilling Spoils dose applies only to 816 the area of material brought to the surface by the well drilling action.
817 The actual dose from each scenario, assuming a summation of the dose from both scenarios 818 equaled 25 mrem/yr is presented in Table 4-3. Therefore, the dose values for each ROC from 819 Table 4-3 were used to derive the AMCG (DOSEAMCG) variable in Equation 4-10 for each 820 scenario.
821 Table 4-1 Basement Inventory LevelsDCGLBS for the Auxiliary Building 822 Radionuclide Inventory LimitGroundwat er Scenario DCGL (mCi)
Drilling Spoils Scenario DCGL (pCi/m2)
(pCi/m2)
Co-60 3.28E+102.28 E+03 3.07E+08 Ni-63 1.15E+108.76 E+04 1.02E+14 Sr-90 9.98E+067.50 E+01 5.25E+10 Cs-134 3.55E+081.59 E+03 5.23E+08 Cs-137 1.25E+088.35 E+02 1.02E+09
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-22 823 824
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-23 Table 4-2 Radionuclide Half-Life(s), Decay Constant(s) and Dose FactorsMixture 825 (a) Dose significant ROC for the Auxiliary Building in accordance with TSD 14-019.
826 (b) Normalized radionuclide mixture for dose significant ROC for Auxiliary Building from Table 20 of 827 TSD 14-019.
828 829 Table 4-3 Dose for Individual Scenarios (DOSEAMCG) 830 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 4.4.2.9.2.
ALARA Calculation 832 The ALARA calculations performed to evaluate the concrete scabbling or shaving remediation 833 activity is presented in Table 4-3 4 for the Auxiliary Building 542 foot elevation. A result for the 834 Conc/DCGL ratio that is less than one would justify remediation whereas a result greater than 835 one would demonstrate that residual radioactivity is ALARA. The Conc/DCGL ratio calculated 836 for the summation of In-Situ Scenarios (Groundwater + Drilling Spoils) was 2.87.
837 4.4.2.10.
Conclusion 838 Concrete structural surfaces below the 588 foot elevation will remain in place after license 839 termination. The site dose contribution from remaining residual radioactivity remaining in these 840 buried plant structures will be accounted for by the BFM. The ALARA analysis based on cost 841 benefit analysis shows that further remediation of concrete beyond that required to demonstrate 842 compliance with the 25 mrem/yr dose criterion is not justified.
843 Radionuclide (a)
Half-Life (yrs)
(yr-1)
Radionuclide 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%
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 0 4-24 Table 4-4 ALARA Analysis for Volumetrically Contaminated Subsurface Structures - Auxiliary Building 542 ft.
844 Cost (in dollars) of remedial action (CostT) = $517,407.37 845 Summation of In-Situ Scenarios (Groundwater + Drilling Spoils) 846 (Groundwater Scenario) 847 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) = 1 848 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 Nuclide Half-Life (yrs)b (yr-1)b (r+)
(r+)N e-(r+)N 1-e-(r+)N
[1-e-(r+)N]
/(r+)
Mixture b GW DCGLBS a (Columns I*J) fi Column K divided by sum Cost Benefit 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)
(Drilling Spoils Scenario) 849 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) = 1 850 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 Nuclide Half-Life (yrs)b (yr-1)b (r+)
(r+)N e-(r+)N 1-e-(r+)N
[1-e-(r+)N]
/(r+)
Mixture b DS DCGLBS a (Columns I*J) fi Column K divided by sum Cost Benefit 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 (a)
From Table 4-1 851 (b) From Table 4-2 852 (b)(c)
Actual drilling spoils area 0.457 m2, 100 m2 used in calculation to ensure 1 person exposed 853
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-25 4.5.
References 854 4-1 U.S. Nuclear Regulatory Commission Regulatory Guide 1.187 Guidance for 855 Implementation of 10 CFR 50.59 Changes, Tests and Experiments - November 2000 856 4-2 U.S. Nuclear Regulatory Commission Regulatory Guide 1.179, Standard Format and 857 Content of License Termination Plans for Nuclear Power Reactors - January 1999 858 4-3 Zion Station, Defueled Safety Analysis Report (DSAR) - September 2014 859 4-4 Zion Nuclear Power Station, Units 1 and 2 Asset Sale Agreement - December 2007 860 4-5 ZionSolutions Technical Support Document 10-002, Technical Basis for Radiological 861 Limits for Structure/Building Open Air Demolition 862 4-6 U.S. Nuclear Regulatory Commission NUREG-1575, Revision 1, Multi-Agency 863 Radiation Survey and Site Investigation Manual (MARSSIM) - August 2000 864 4-7 U.S. Nuclear Regulatory Commission Docket Number 50-295, Facility Operating 865 License Number DPR-39 (for Unit One) 866 4-8 U.S. Nuclear Regulatory Commission Docket Number 50-304, Facility Operating 867 License Number DPR-48 (for Unit Two) 868 4-9 U.S. Nuclear Regulatory Commission NUREG-1757, Volume 2, Revision 1, 869 Consolidated Decommissioning Guidance - Characterization, Survey, and 870 Determination of Radiological Criteria, Final Report - September 2003 871 4-10 U.S. Nuclear Regulatory Commission, NUREG/BR-0058, Revision 4, Regulatory 872 Analysis Guidelines of the U.S. Nuclear Regulatory Commission - September 2004 873 4-11 U.S. Nuclear Regulatory Commission, NUREG-1496, Volume 2, Generic 874 Environmental Impact Statement in Support of Rulemaking on Radiological Criteria for 875 License Termination of NRC-Licensed Nuclear Facilities - July 1997 876 4-12 U.S. Nuclear Regulatory Commission, NUREG-1530, Reassessment of NRCs Dollar 877 per Person-Rem Conversion Factor Policy - December 1995 878 4-13 ZionSolutions Technical Support Document 14-016, Description of Embedded Pipe, 879 Penetrations, and Buried Pipe to Remain in Zion End State 880 4-134-14 U.S. Nuclear Regulatory Commission, NUREG/CR-5884, Volume 2, Revised 881 Analyses of Decommissioning for the Reference Pressurized Water Reactor Power 882 Station - November, 1995 883 4-144-15 ZionSolutions Technical Support Document 14-013, Zion Auxiliary Building 884 End State Estimated Concrete Volumes, Surface Areas, and Source Terms 885
ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 1 4-26 4-154-16 ZionSolutions Technical Support Document 14-019, Radionuclides of Concern 886 for Soil and Basement Fill Model Source Terms 887