Safety Standards for Decommissioning Activities Koji OKAMOTO The University of Tokyo (Chair of AESJ Decommissioning Standard Committee)
Status of decommissioning in Japan Nuclear Power Plant (NPP) under decommissioning Tokai 1 NPP(GCR) Mihama NPP Unit 1 (PWR) Fugen NPP(ATR) Mihama NPP Unit 2 (PWR) Hamaoka NPP Unit 1(BWR) Genkai NPP Unit 1 (PWR) Hamaoka NPP Unit 2(BWR) Tsuruga NPP Unit 1 (BWR) Shimane NPP Unit 1 (BWR) Transition to decommissioning Ikata NPP Unit 1(PWR) Monju NPP (FBR) 1
Points on Decommissioning Management (no R&D) Status and conditions change every day Scheduling and work control Human Resource and Budget control Graded Approach Decreasing amount of radioactive materials Comprehensive Risk Reduction Focus on high-risk task Minimize radioactive waste
Project Management Decommissioning activities are completely different from Operation Optimize under the boundary conditions Confinement of radioactive materials Prevention of radioactive material release Mitigation of accidents Workers safety not only radiation, but also health and injury Minimize radioactive waste Organization and budget should be identical from Operating organization
Graded Approach Risk on radioactive material release Radioactive materials inventory Characterization of Radioactive materials Good practices in US Decommissioning Inspection Program (Instead of ROP) Licensee could modify or remove SSCs without permission of NRC NRC checks overall determination by licensee
for Safety Decommissioning AESJ Standard (Atomic Energy Society of Japan) Safety Requirement for Decommissioning Decommissioning Planning Safety Assessment, and so on Decommissioning Practice Seismic protection, and so on Low-level Radioactive Waste Safety storage for VLLW, and so on Clearance methods
Work flow of preparatory tasks for decommissioning (1/2) 1 Radiological characterization Data flow 1 Radiological characterization 2 Investigation for plant characteristics 3Planning for To evaluate radioactivity inventory, which are information about both amount and characteristics of activated materials and contaminated materials. Iteration loop 4Safety assessment for Time 5 Estimation for decommissioning cost 2 Investigation for plant characteristics To obtain the information about current situation of the NPP, by referencing to the design charts, the maintenance records, the operation history etc.,
Work flow of preparatory tasks for decommissioning (2/2) 1 Radiological characterization 2 Investigation for plant characteristics Data flow 3 Planning for To design decontamination actions and dismantling actions and planning waste processing. To schedule the decommissioning activities. 3Planning for Iteration loop 4Safety assessment for Time 5 Estimation for decommissioning cost 4 Safety assessment on To assess public exposure, occupational exposure and environmental impact due to the decommissioning. To assess the occupational safety. 5 Estimation for decommissioning cost To estimate the decommissioning cost To review the planning to optimize the cost
AESJ Standards Series for Decommissioning Published standards Planning Phase Planning of the Commercial Power Reactor Decommissioning (AESJ-SC-A002:2011)[standard] Planning of Decommissioning Research Reactor and Fuel Facilities (AESJ-SC-A007:2013)[standard] Practice Phase Practice of the Nuclear Facilities Decommissioning (AESJ-SC-A003:2014) [guide] Seismic Safety Guide for Nuclear power Reactor in Decommissioning (AESJ-SC-A006:2013) [guide]
AESJ Standards Series for Decommissioning Under revision or preparing for publication Safety requirement General Safety Requirements for Decommissioning By AESJ [standard] Planning phase Planning the Commercial Power Reactor Decommissioning (revision) [standard] Safety Assessment of Decommissioning Activities [standard] Guideline of Radiological Characterization for Decommissioning [guide] Guideline of Investigation for plant characteristics for Decommissioning [guide]
- The IAEA Safety Standard Series vs. The Standards Series for Decommissioning by AESJ - SF Safety Fundamentals General Safety Requirements for Decommissioning By AESJ GSRs SSRs GSGs SSGs SRS General Safety Requirements Specific Safety Requirements General Safety Guides Specific Safety Guides Safety Report Series Planning of the Commercial Power Reactor Decommissioning (revision) Safety Assessment on Decommissioning Activities Practice of the Nuclear Facilities Decommissioning Seismic Safety Guide for Nuclear Power Reactor in Decommissioning Guideline of Radiological Characterization Guideline of Investigation for plant characteristics Hierarchy of IAEA SSS Standard Series by AESJ
Relation between tasks in decommissioning and publications by AESJ Tasks Overall period of decommissioning All tasks in preparatory tasks for decommissioning Safety assessment for decommissioning activities Radiological characterization Investigation for plant characteristics Title of Standard or Guideline General Safety Requirements for Decommissioning By AESJ Planning the Commercial Power Reactor Decommissioning (revision) Safety Assessment of Decommissioning Activities Guideline of Radiological Characterization for Decommissioning Guideline of Investigation for plant characteristics for Decommissioning Planning for / All activities in all practice period Practice of the Nuclear Facilities Decommissioning Seismic Safety Guide for Nuclear power Reactor in Decommissioning
Planning phase Practice phase 1 Radiological characterization 2 Investigation for plant characteristics Decontamination of SSCs Dismantling of SSCs 3Planning for SSCs : Systems, Structures, components Waste processing 4 Safety assessment for Decontamination of SBs 5 Estimation for decommissioning cost Dismantling of SBs Iteration loop Data flow SBs : Structures, Buildings Waste processing Time
General Safety Requirements for Decommissioning By AESJ Planning the Commercial Power Reactor Decommissioning (revision) Practice of the Nuclear Facilities Decommissioning 13
Summary Decommissioning is Management Planning of decommissioning is key for the safety AESJ published Decommissioning standards Safety requirements Management Database and Best Practice Graded approach