Decommissioning Health Physics presents many of the technical issues and challenges that arise during the planning and implementation of decommissioning and decontamination (D&D) projects. The focus is on the final status survey performed during the later stages of decommissioning projects. It expands upon and provides greater technical detail than Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) in areas of survey design strategies.Featuring a number of completely worked examples of final status survey strategies, the book prepares the reader for the real-world application of MARSSIM at D&D projects. One chapter is devoted to the specific decommissioning concerns relevant to specific facility types, power reactors, uranium and thorium facilities and sites, and universities or other research facilities. The book thoroughly discusses practical applications of statistics in the context of decommissioning projects, from elementary statistics to hypothesis testing for a number of applications including data comparisons between the regulator and licensee, normality testing of the data, and survey unit compliance decisions.Decommissioning Health Physics will be beneficial for the planners, designers, and reporters of final status survey results as well as health physics technicians who will benefit from practical chapters on instrumentation and survey procedures.
Author(s): Eric.W. Abelquist
Edition: 1
Year: 2002
Language: English
Pages: 350
Contents......Page 6
Preface......Page 12
Acknowledgments......Page 13
1 Introduction: current issues in decommissioning and the MARSSIM overview......Page 16
Questions......Page 22
2.1 Decommissioning options......Page 23
2.2 Decommissioning project phases......Page 27
2.3 Radiological surveys performed during decommissioning......Page 29
2.4 Regulatory agency interface when designing the MARSSIM surveys......Page 31
2.4.1 NRC standard review plans......Page 32
2.4.2 Verification process......Page 34
2.4.3 Verification program experiences and lessons learned......Page 40
Questions......Page 46
3.1 Introduction......Page 47
3.2 Objectives of characterization and data quality objectives (DQOs)......Page 51
3.3 Characterization survey design and considerations......Page 52
3.4 Characterization survey activities......Page 57
3.4.2 Land area surveys......Page 58
3.5 Characterization survey results to support the MARSSIM final status survey design......Page 60
Questions and problems......Page 62
4 Guidelines and dose-based release criteria......Page 64
4.1 Historic release criteria and guidance documents......Page 65
4.2 Dose-based release criteria and the NRC decommissioning rule-making......Page 70
4.3 Clearance of materials and ANSI N13.12......Page 76
Questions and problems......Page 78
5 Exposure pathway modeling—DCGLs and hazard assessments......Page 79
5.1 Screening versus site-specific—when is it time to go beyond the screening DCGLs?......Page 80
5.2.1 The NRC Policy and Guidance Directive PG-8-08......Page 82
5.2.2 NUREG/CR-5512 and NUREG-1549......Page 84
5.2.3 Pathway modeling parameters......Page 87
5.3 Modeling codes......Page 89
5.3.1 RESRAD and RESRAD—build models......Page 90
5.3.2 D&D model......Page 91
5.4 Determination of DCGLs and area factors......Page 92
5.4.1 Dose modeling to obtain DCGLs......Page 93
5.4.2 Modeling to obtain area factors......Page 102
5.5 Hazard assessments—an early application of dose-based release criteria?......Page 106
5.5.1 Hazard assessment for contaminated roof panels at a uranium site......Page 107
5.5.2 Hazard assessment for contaminated underground pipes at a sealed source facility......Page 115
Questions and problems......Page 118
6 Preliminary survey design concerns and application of DCGLs......Page 120
6.1 Direct application of DCGLs......Page 121
6.2 Use of DCGLs for sites with multiple radionuclides......Page 122
6.2.1 Use of surrogate measurements......Page 125
6.2.2 Gross activity DCGLs for surface activity......Page 134
6.2.3 Use of the unity rule......Page 137
Questions and problems......Page 139
7 Background determination and background reference areas......Page 141
7.1 Background reference areas and related considerations......Page 142
7.2 Surface material backgrounds......Page 144
7.3 Scenario B survey design—indistinguishable from background......Page 146
7.4 Scenario A versus scenario B final status survey designs......Page 152
Questions and problems......Page 156
8.1 Calibration for surface activity measurement instruments......Page 158
8.2 Overview of survey instrumentation and philosophy of instrument selection......Page 160
8.3.1 Overview of field survey instruments......Page 162
8.3.2 Conventional survey instrument types......Page 164
8.3.3 Advanced survey instrument types......Page 170
8.3.4 Environmental effects on survey instrument operation......Page 175
8.4 Determination of instrument efficiency for surface activity measurements......Page 178
8.5 Survey instrumentation for exposure rate measurements......Page 184
8.5.2 Micro-R and micro-rem meters......Page 185
8.6 Laboratory instrumentation......Page 187
Questions and problems......Page 188
9 Detection sensitivity—static and scan MDCs......Page 190
9.1 Critical level and detection limit......Page 191
9.2 Static MDC......Page 201
9.3.1 Signal detection theory for scanning......Page 203
9.3.2 Decision processes of the surveyor (human factors)......Page 205
9.3.3 Scan MDCs for structure surfaces......Page 208
9.3.4 Scan MDCs for land areas......Page 217
9.3.5 Scan MDCs for multiple contaminants for structure surfaces and land areas......Page 225
9.3.6 Empirically determined scan MDCs......Page 233
Questions and problems......Page 235
10 Survey procedures and measurement data interpretation......Page 239
10.1.1 Surface efficiency (ε[sub(s)])......Page 240
10.1.2 Building material—specific backgrounds......Page 246
10.2 Scanning building surfaces and land areas......Page 250
10.3.1 Calibration standards and geometries for soil analyses......Page 253
10.3.2 Interpreting gamma spectrometry data......Page 254
Questions and problems......Page 257
11.1 Basic population statistics and confidence interval testing......Page 259
11.1.1 Basic statistics......Page 260
11.1.2 Confidence interval testing......Page 262
11.2.1 Binomial distribution......Page 263
11.2.2 Poisson distribution......Page 265
11.2.3 Normal distribution......Page 266
11.2.4 Student's t distribution......Page 267
11.3 Hypothesis testing......Page 268
11.3.1 Hypothesis testing fundamentals and examples......Page 269
11.3.2 Chi-square test—a hypothesis test for evaluating instrument performance......Page 274
Questions and problems......Page 276
12 The MARSSIM final survey design and strategies......Page 277
12.1.1 NUREG/CR-2082 Guidance......Page 278
12.1.2 NUREG/CR-5849 Guidance......Page 280
12.2 Overview of the MARSSIM survey design......Page 284
12.2.1 Sign test example—Co-60 in soil......Page 285
12.2.2 WRS test example—uranium and thorium in soil......Page 293
12.3 Surface activity measurements: Wilcoxon Rank Sum test or Sign test?......Page 299
12.3.1 Surface activity measurements......Page 300
12.3.2 WRS test for surface activity assessment......Page 301
12.3.3 Sign test for surface activity assessment......Page 303
12.3.4 Simulation study conceptual design......Page 308
12.4 Comparison of the MARSSIM and NUREG/CR-5849 final status surveys for nuclear power plant decommissioning projects......Page 309
12.5 Annotated MARSSIM examples......Page 313
12.5.1 Example 1—class 1 interior survey unit......Page 314
12.5.2 Example 2—class 2 interior survey unit......Page 317
12.5.3 Example 3—class 1 exterior survey unit......Page 320
12.5.4 Example 4—class 1 interior survey unit with multiple contaminants......Page 323
12.6 The MARSSIM final status survey design strategies—understanding the power curve......Page 329
Questions and problems......Page 337
13 The MARSSIM data reduction......Page 339
13.1 Data quality assessment for the Sign test for Co-60 in soil......Page 340
13.2 Data quality assessment for the WRS test for uranium and thorium in soil......Page 348
13.3 What if the survey unit fails?......Page 351
Questions and problems......Page 353
14.1 Uranium sites......Page 355
14.2 Thorium and radium sites......Page 360
14.3 Power reactor......Page 364
14.4 University/research facilities......Page 367
Questions and problems......Page 368
15 Final status survey reports......Page 369
15.1 Final status survey report content......Page 370
15.2 Reporting survey results: measurement uncertainties and error propagation......Page 373
Questions and problems......Page 377
16.1 Test for data normality......Page 378
16.1.1 Shapiro–Wilk (W test)......Page 379
16.1.2 D'Agostino test......Page 381
16.2 Applications of statistics in decommissioning—comparison of data sets......Page 382
16.2.1 t test with unequal variances: evaluating automated soil sorter performance......Page 384
16.2.2 Pairwise t test: evaluating 'wet' versus processed gamma spectroscopy results......Page 386
16.2.3 Confirmatory analyses using non-parametric statistics......Page 389
16.3 Case study: comparing Cs-137 concentration in a class 3 area with background reference area using both the t test and the WRS test......Page 392
16.3.1 Two-sample t test......Page 393
16.3.2 Mann–Whitney test: comparing Cs-137 concentrations in a class 3 area with a background reference area......Page 405
Questions and problems......Page 409
17 International decommissioning perspectives......Page 410
Solutions to selected questions and problems......Page 413
A Radionuclide and natural decay series characteristics......Page 429
B The MARSSIM WRS and Sign test sample sizes (from the MARSSIM tables 5.3 and 5.5)......Page 438
C Example decommissioning inspection plan for final status survey program......Page 441
References......Page 446
H......Page 451
S......Page 452
W......Page 453
