R&D of the Instrumentation Systems for Severe Accidents in Nuclear Power Plants. (Summary)

Transcription

1 1 SA 計装開発情報 : クラス C R&D of the Instrumentation Systems for Severe Accidents in Nuclear Power Plants (Phase Ⅰ) (Summary) May, 2012

2 Contents 2 1. Purpose of R&D 2. Promoting Organization 3. Role of Councils 4. Implementation Plan for fiscal years 2011 to R&D Plan Schedule

3 1.Purpose of R&D 3 After TEPCO's Fukushima Daiichi Nuclear Power Station Accident (TEPCO's Fukushima Daiichi Accident) on March 11, 2011, we launched into the research & development of instrumentations and systems to contribute to the improvement of the safety of Nuclear Power Plants (NPPs). In order to achieve the safety of NPPs at the highest global standards, enhancements to the safety technology and infrastructure are now strongly required. Nuclear Emergency Response Headquarters (Government of Japan) has published reports, Report of Japanese Government to IAEA Ministerial Conference on Nuclear Safety (June, 2011) and Additional Report of Japanese Government to IAEA - Accident at TEPCO's Fukushima Nuclear Power Stations (The Second Report), on the lessons learned from TEPCO's Fukushima Daiichi Accident and the approaches to the findings. In this project, we research and develop the highly difficult matters of improvement on safety measures in NPPs based on one of the findings of the above lessons learned Enhancement of Instrumentation systems for Reactor and Containment Vessels (*1). 1 (14) Enhancement of instrumentation for reactors and PCVs The Instrumentation System for Reactor and Containment Vessels did not completely work during the severe accident. It made it difficult to immediately and accurately grasp important information (e.g., water level and pressure for RV, the source of radiation and the amount of released radioactive materials). Because of this, enhancements of Instrumentation System for Reactor and Containment Vessel is necessary for the system to work sufficiently during a severe accident. Working Team for the Sever Accident Instrumentation Systems R&D

4 2.Promoting Organization 4 Steering Meeting Report Evaluate, Advise Advisory Committee (Third party experts) Chairperson, secretariat Report project plans and progresses Approve, direct on basic principle, etc Working Team for the Severe Accident Instrumentation Systems R&D Prepare project/development plan Approve Primary members of Working Team BWR WG (BWR Electric Power Companies, Hitachi-GE and Toshiba) PWR WG (PWR Electric Power Companies and MHI) B/P Manufacturers Working Groups

5 3.Role of Councils 5 (1) Steering Meeting In the steering meeting, Japanese government, electric power companies and manufactures participate to determine basic principles of this project. The steering meeting approves project plans and development plans which the Working Team for the Severe Accident Instrumentation Systems R&D has established. The steering meeting also performs checks and reviews on the progress and results. Moreover, the steering meeting organizes the advisory committee, which consists of experts from third party organizations. (2) Advisory Committee The advisory committee strictly evaluates and advises the support entities activities for these projects. The purpose of the advisory committee is to make this project efficient and effective. (3) Working Team for the Severe Accident Instrumentation Systems R&D The main members of the Working Team for the Severe Accident Instrumentation Systems R&D are electric companies and support entities. The project plan and the development plan are settled by Working Team for the Severe Accident Instrumentation Systems R&D. In order to facilitate the management, the Working Team for the Severe Accident Instrumentation Systems R&D is organized. Each working group whose main members are to support entities promotes specific research based on the project plans or the development plans. (*) Basic principle : the mid-term principle regarding the technical development, costs and organization Project plan : the specific plan regarding the technical development, costs and organization Development plan : the detailed plan of each technical development

6 4. Implementation Plan for fiscal years (1 of 4) 6 (1)Defining the requirements for instrumentation systems (fiscal year 2011) (A) Selection of parameters required for Severe Accident (SA) Based on TEPCO's Fukushima Daiichi Accident, we will extract and define the measurement parameters to be required for SA management in the PRV,RV Systems and Spent Fuel Pool Systems for this research and development. While defining the parameters, a representative scenario during the SA will be applied for evaluation. (B) Setting for the environment conditions, etc. We will define the environment conditions and the design conditions to be considered when the object parameter is measured. These conditions are based on the actual measurement values in TEPCO's Fukushima Daiichi Accident including estimated values and analytic values. (C) Defining the requirements According to above (A) and (B), we will define the requirements for the development of instrumentation systems.

7 4. Implementation Plan for fiscal years (2 of 4) 7 (2) Settling the primary development plan (fiscal year 2012) (A) Public Offering of Technical Ideas We will hold a "Public Offering of Technical Ideas" to examine instrument systems developed in this project and to accept ideas widely from industries besides the nuclear industry. At the appearance of an idea that is feasible to this project, we will investigate a development plan. (B) Setting for the basic specifications on instrumentation systems We will set the basic specifications on the specific instrumentation system which satisfy the requirements such as process conditions, measuring ranges, power sources, etc. (C) Study of the development plan on instrumentation systems Based on the basic specifications (above (B)), we will inquire into whether the existing instrumentation technology is feasible. If difficult, we will investigate new instrumentation technology, and formulate a development plan. (D) Investigate the development plan priority After the development plan is formulated, we will assign priority of the development entries and decide on the implementation to the extent of this research phase I.

8 4. Implementation Plan for fiscal years (3 of 4) 8 (3) Development of the SA instrumentation systems (from fiscal years 2012 to 2014) Based on (1) and (2) explained in the previous slides, we will produce a prototype instrumentation system to develop and on which conduct basic tests and analyses. After the fundamental specification is satisfied, we will confirm the adaptability for the actual production system or feasibility of the system by performing a qualification test. The progress of work will be divided into two parts; one is the development process in which the existing technology is applied, and the other is the process in which advanced technology is applied. These two types of developments will be managed separately. The development which has priority on speed will be completed by fiscal year The development with advanced technology will be completed by fiscal year (A) Design and production of prototype instrumentation system Based on the development entry formulated in the previous slide (2), we will design the instrumentation system in detail and produce a prototype. (B) Basic test and analysis on instrumentation systems We will perform the basic test and analysis in order to confirm the fundamental specification on the prototype instrumentation system. (C) Qualification tests on instrumentation systems Given the resistance to environment and aging deterioration, we will perform the qualification test to prove the practicability.

9 4. Implementation Plan for fiscal years (4of4) 9 (4) Drawing up standards and guidelines (fiscal years ) We will prepare drafts of standards and guidelines of the instrumentation system which has acquired the specification formulated in the previous slide (3). Concurrently, we will investigate overseas standards. (A) Investigation of overseas standards We continue to research overseas standards and extract the requirements for the severe accident instrumentation system. (B) Drawing up standards and guidelines We will prepare drafts of standards and guideline on the required specification on the developed severe accident instrumentation system. (5) Summary of outcomes (fiscal year 2014) We will conclude and summarize the outcomes from (1) to (4) as a report.

10 5.R&D Plan Schedule 10 R&D Plan contents Fiscal 2011 Fiscal 2012 Fiscal 2013 Fiscal Defining the requirements for instrumentation systems 1 Selection of parameters required for SA 2 Setting for the environment conditions and etc. of SA 3 Defining the requirements 2.The settling of the primary development plan 1 Public offering of technical ideas 2 Setting for the basic specification on instrumentation systems 3 Study of the development plan on instrumentation systems 4 Investigation of the priority of the development plan 3.The development of the SA instrumentation systems 1 Design and prototype production of instrumentation systems 2 Basic test and analysis on instrumentation systems 3 Qualification tests on instrumentation systems 4.Drawing up standards and guidelines for SA 1 Investigation of overseas standards 2 Drawing up standards and guidelines PhaseⅡ: The operation test will be performed if necessary (from 3Q/2014) System Installation for actual NPPs : after completing tests (from 1Q/2014) Working Team for the Sever Accident Instrumentation Systems R&D

11 11 Attachment Development Plan (Draft)

12 Development Instrumentation Parameters(Draft) 12 1)Water Level 1-1) PCV ( D/W S/C) 1-2) RPV 1-3) SFP 1-4) Thimble tube Room 2)Dose Rate 2-1) D/W 2-2) R/B 3)Hydrogen 3-1) D/W S/C 3-2) R/B 3-3) CV 3-4) Annulus 4)Temperature 4-1) Thimble tube Room 4-2) D/W S/C, RPV Surface

13 Development Plan (Draft) Thermocouple Type RPV Level Monitor (Example for BWR Application) [Existing System] The system measures the differential pressure corresponded to the reactor water level outside PCV via instrumentation tubing from the RPV. Condenser pot keeps constant water level as the reference pressure. Existing System (Differential Pressure Type) Range of measurement PCV In TEPCO's Fukushima Daiichi Accident, high temperature conditions inside PCV caused evaporation of referential water leading to incorrect water level indications. Measuring the water level lower than BAF was difficult to achieve. Condenser Pot (Reference leg) RPV Existing Neutron Detector Tube Thermocouple with heater [Development Goal] Sensors installed inside RPV measures water level from the fuel area to the vessel bottom at SA conditions. It is also able to detect core damage. [Example ] Heater Enlarged Target System Insulator Thermocouple 13 Development Schedule 1.Design, manufacture 2.Basic test 3.Demostration test DP sensor BAF 2012/B 2012/E 2013/B 2013/E 2014/B New range of measurement Level meter Thermocoupl e Independent type thermocouple with heater Heat Isolation Heater Differential type thermocouple Jacket tube Enlarged Thermocouple with differential type heater The sensor detects a level with the difference of the temperature increase between liquid and steam when the heater activates. Working Team for the Sever Accident Instrumentation Systems R&D

14 Development Plan (Draft) Hydrogen Gas Monitor Inside the PCV (Example for BWR Application) 14 [Existing System] The system measures hydrogen concentration in sampled gas which is drawn to the outside from the PCV. The sample is chilled and dehumidified. (Sampling method) Hydrogen Gas Monitor inside PCV did not work in TEPCO's Fukushima Daiichi Accident due to the sampling system failure caused by the loss of power supply and coolant. Hydrogen Gas Monitor for R/B did not exist. [Development Goal] New sensors installed inside the PCV and R/B measure hydrogen concentration under SA conditions. Indicator % Development Schedule 1.Design, manufacture 2.Principle test 3.Demostration test Existing System Moisture separator Pressure rising pump Drain Hydrogen Sensor Sample pump Coolant Drain Cooler Steam separator Sample return Hydrogen Gas Monitor inside PCV Gas sampling R/B RPV PCV 2012/B 2012/E 2013/B 2013/E 2014/B Hydrogen Sensor Target System Signal Indicator <Example of Principle> Hydrogen storage material % Resistanc e change measurin g Battery Electrod e Measuring resistance change caused by hydrogen storage. Working Team for the Sever Accident Instrumentation Systems R&D

15 Development Plan (Draft) Hydrogen Gas Monitor Inside the CV (Example for PWR Application) 15 [Existing System] The system measures hydrogen concentration in sampled gas which is drawn to the outside from the CV. The sample is chilled and dehumidified. (Sampling method) Hydrogen Gas Monitor did not work in TEPCO's Fukushima Daiichi Accident due to the sampling system failure caused by the loss of power supply and coolant. [Development Goal] New sensors installed inside the CV measure hydrogen concentration under SA conditions. They are highly robust and need no sampling facilities. Existing System Target System Moisture 湿分分離器 Separator Cooler 冷却器 Hydrogen Sensor 水素分析器 Drain ドレン Coolant 冷却水ポンプ Pump Gas カ スサンフ リンク Sampling 蒸気発生器 SG 加圧器 PZR RV 原子炉容器 Hydrogen Sensor 水素センサ Indicator 表示装置 Signal 電気信号 % バッテリー Battery <Example of Principle> mete 電圧計 Volt r Referenc e 基準水素 Measuring gas 測定水素 Development Schedule 2012/B 2012/E 2013/B 2013/E 2014/B 1.Design, Manufacture 2.Principle test 3.Demostration test Hydrogen ion conductive solid electrolyte 水素イオン導電性固体電解質 Electrode 電極 Difference in hydrogen concentration generates voltage. Working Team for the Sever Accident Instrumentation Systems R&D