Supporting Report 2Repository Design and Engineering Technology

Chapter I Introduction

This Supporting Report provides a summary of the results of research and developmentstudies on repository design and engineering technology that have been conducted by theJapan Nuclear Cycle Development Institute (hereafter“JNC”). The contents of the reportbasically respond to the objectives and issues relating to repository design and engineeringdescribed in a report published in 1997 by the Advisory Committee on Nuclear Fuel CycleBackend Policy of the Atomic Energy Commission of Japan entitled “Guidelines on Researchand Development Relating to the Geological Disposal of High-Level Radioactive Waste inJapan” (hereafter the “AEC Guidelines”). In addition, the report supports the content ofChapter IV of the Project Overview Report with a view to ensuring transparency andtraceability.

1.1 Objectives

In H12, the objectives of the research and development relating to the design, manufacture,installation and construction of the engineered barrier system and the disposal facility are:

• to propose design requirements for a safe and reliable engineered barrier system anddisposal facility and

• to show that the engineered barrier system (EBS) and the disposal facility can beconstructed using currently available engineering technologies or technical advancesexpected in the near future.

At the same time, in order to manage the disposal site and to confirm repository performance,it is necessary to review the information and measurement methods required at each stage ofrepository development, from the start of construction until closure, and to prepare thetechnical basis for the management of a potential future disposal site.

1.2 Content and structure of Supporting Report 2

Supporting Report 2 consists of eight chapters. In this Chapter, the objectives and content aredescribed. In Chapter II, based on the geological disposal concept and basic safety concept inJapan, designs for the engineered barrier system (EBS) and the disposal facility are discussedand the various components of the repository are described. The factors influencing the basicdesign concepts for engineered barrier systems and disposal facilities are discussed in ChapterIII , and requirements for their investigation are provided.

In Chapter IV, the design concepts and design requirements for the engineered barrier systemand disposal facility are discussed, taking into consideration the wide range of geologicalenvironments in Japan. The geological environment at a site where the EBS would beinstalled, and the changes in the near-field environment following installation of the EBS, areconsidered in the review of the design requirements, based on the information (thermal andmechanical properties of the host rock, groundwater hydraulic properties and groundwatergeochemistry, etc.) on the geological environment given in H12 Supporting Report 1 (JNC,2000). Consideration is given to the relationship between design requirements and the