Draft Design Safety Requirements for Proposed Nigeria NPPs to SMRs and probable Application Challenges G. O. Omeje

Transcription

1 Draft Design Safety Requirements for Proposed Nigeria NPPs to SMRs and probable Application Challenges G. O. Omeje TM on Challenges in the application of Design Safety Requirements for NPPs to SMRs 4th - 8th 1

2 DR1 Safety Objectives & Concepts Fundamental Safety Objective: protect people and the environment from harmful effects of ionizing radiation to achieve the highest standards of safety that can reasonably be achieved applies for all stages in the lifetime of a nuclear power plant, including planning, siting, design, manufacture, construction, commissioning and operation, as well as decommissioning, associated transport of radioactive material and the management of spent nuclear fuel and radioactive waste Radiation Protection Objective Technical Safety Objective TM on Challenges in the applications of Design Safety Requirements for NPPs to SMRs 4th - 8th 2

3 DR1 Safety Objectives & Concepts 1.2 Application of the Technical Safety Objective Dose Acceptance Criteria Safety Goals TM on Challenges in the applications of Design Safety Requirements for NPPs to SMRs 4th - 8th 3

4 DR2 Management of Safety in Design (1) An applicant for a licence to construct and/or operate a NPP shall be responsible for ensuring that the design submitted to the Authority meets all applicable safety requirements. Design organization Management System for Plant Designs Safety of the plant design throughout the lifetime of the plant 4

5 DR3 Principal Technical Requirements- (1)Fulfilment of the following fundamental safety functions for a NPP shall be ensured for all plant states: Control of reactivity Removal of heat from the reactor and from the fuel store and Confinement (2) The design shall establish a set of OLC for safe operation of the NPP. TM on Challenges in the application of Design Safety Requirements for NPPs to SMRs 4th - 8th 5

6 DR3 Principal Technical Requirements 3.1 Fundamental safety functions Physical separation and independence of safety systems Safety classification 3.2 (OLC) Operational Limits and Conditions Operational limits and conditions for safe operation TM on Challenges in the application of Design Safety Requirements for NPPs to SMRs 4th - 8th 6

7 DR3 Other Design Considerations Safety systems, and safety features for design extension conditions, of units of a multiple NPP Systems containing fissile material or radioactive material NPPs used for cogeneration of heat and power, heat generation or desalination Control of access to the plant Prevention of unauthorized access to, or interference with, items important to safe Prevention of harmful interactions of systems important to safety Interactions between the electrical power grid and the plant 7

8 DR4 Design for a NPP The design for a NPP shall ensure that the plant and items important to safety have the appropriate characteristics to ensure that safety functions can be performed with the necessary reliability, that the plant can be operated safely within the operational limits and conditions for the full duration of its design life and can be safely decommissioned, and that impacts on the environment are minimized.) The design basis for each item important to safety shall be systematically justified and documented. 8

9 DR4 General Plant Design Categories of plant states Design basis for items important to safety Design basis accidents Design extension conditions Combinations of Events Internal and external hazards Postulated initiating events 9

10 DR4 Design Rules & Limits (1/2) Design limits A set of design limits consistent with the key physical parameters for each item important to safety for the nuclear power plant shall be specified for all operational states and for accident conditions. 10

11 DR4 Design Rules & Limits (2/2) Engineering design limits The engineering design rules for items important to safety at a nuclear power plant shall be specified and shall comply with the relevant national or international codes and standards and with proven engineering practices, with due account taken of their relevance to nuclear power technology. 11

12 DR4 Design for Reliability (1/6) Reliability of items important to safety The reliability of items important to safety shall be commensurate with their safety significance. 12

13 DR4 Design for Reliability(2/6) Common-cause failures The design of equipment shall take due account of the potential for common cause failures of items important to safety, to determine how the concepts of diversity, redundancy, physical separation and functional independence have to be applied to achieve the necessary reliability. 13

14 DR4 Design for Reliability (3/6) Single failure (SF) criterion The SF criterion shall be applied to each safety group incorporated in the plant design. Spurious action shall be considered to be one mode of failure when applying the single failure criterion to a safety group or safety system. The design shall take due account of the failure of a passive component, unless it has been justified in the SF analysis with a high level of confidence that a failure of that component is very unlikely and that its function would remain unaffected by the PIE TM on Challenges in the application of Design Safety Requirements for NPPs to SMRs 4th - 8th 14

15 DR4 Design for Reliability (4/6) Fail-safe design (FSD) The concept of FSD shall be incorporated, as appropriate, into the design of systems and components important to safety. The principle of FSD shall be applied to the design of SSCs important to safety to enable plant systems to pass into a safe state if a system or component fails, with no necessity for any action to be taken. 15

16 DR4 Design for Reliability (5/6) 4.6 Design for optimal operator performance. Systematic consideration of human factors, including the human machine interface, shall be included at an early stage in the design process for a nuclear power plant and shall be continued throughout the entire design process. 16

17 DR4 Design for Reliability (6/6) 4.7 Application of defence in depth The design of a nuclear power plant shall incorporate defence in depth. The levels of defence in depth shall be independent as far as is practicable. Defence-in-depth shall be achieved at the design phase through application of design provisions specific to the five levels of defence. 17

18 DR4 Design for Reliability 4.8 Interfaces of Safety with Security and Safeguards Interfaces of safety with security and safeguards Safety measures, nuclear security measures and arrangements for the State system of accounting for, and control of, nuclear material for a nuclear power plant shall be designed and implemented in an integrated manner so that they do not compromise one another. 18

19 DR5 Design of Specific Plant Systems This chapter includes; Performance for Fuel Element and Assemblies Reactor Coolant Systems Containment Structure and Containment System Instrumentation and Control Systems Emergency Power Supply Auxiliary Systems Fuel Handling and Storage Systems Radiation Protection 19

20 Challenges Requirements still in draft form Insufficient competence Licensability of SMRs due to unproven technology Non competitiveness (Bid Invitation) Lack of Capacity to verify & validate safety analysis for NPPs and SMRs 20