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Session Chair: Belle Upadhyaya, University of Tennessee, Knoxville, United States of America
Developments in Instrumentation and Control System Sensors and Cables for Small Modular Reactors
Alexander H. Hashemian1, Jacob R. Houser1, Shawn N. Tyler1, Edwin T. Riggsbee1, Belle R. Upadhyaya2
1Analysis & Measurement Services Corporation (AMS); 2University of Tennessee
Small modular reactors (SMRs) are under development to provide clean electricity and support new applications for nuclear energy such as industrial heat generation and water desalination. In addition, SMRs offer improved passive safety features, greater site flexibility, and reduced construction costs relative to large-scale nuclear power plants (NPPs). However, there are fundamental SMR design characteristics that present unique challenges to conventional NPP components, systems, and processes that must be addressed in the near term to facilitate timely deployment of SMRs.
Instrumentation and control (I&C) system technologies, in particular, must be developed to support the needs of SMRs. As with any NPP, the safe and efficient operation of an SMR requires accurate and timely measurement of reactor coolant system (RCS) process parameters such as temperature, pressure, level, flow, and neutron flux. For some SMR applications, conventional nuclear grade I&C sensors and cables may not be viable options. Furthermore, emerging sensors under development at national laboratories and universities may be well suited for SMR applications but far from commercial readiness.
This paper describes on-going research and development (R&D) conducted by the authors to evaluate sensors under consideration by SMR vendors for RCS process parameter measurements. More specifically, static and dynamic performance is characterized to determine if a given sensor can satisfy SMR plant technical specifications. New laboratory and in-situ sensor test methods have been developed to support this effort. In addition, several common I&C cables are being subjected to a high-temperature vacuum environment in order to evaluate the survivability of various cable insulation materials at the harsh conditions anticipated in containment of the NuScale SMR. The goal of this R&D funded by the U.S. Department of Energy (DOE) is to develop I&C technical guidance, technologies, products, and services to directly support the deployment of the first U.S.-based SMR by the mid-2020s.
Use of simplified model predesign tool for comparing nuclear reactor: Comparison of two loops PWR designs
This paper describes the COPERNIC (French acronym for Pre-designing and Evaluation Code of Nuclear Innovative Reactors using Concurrent Engineering methods) tool used for evaluations of innovative nuclear systems. Since several years, the French Atomic and Alternative Energy Commission (CEA) has been interested in the evaluation of innovative reactor concepts. CEA developed a specific tool, called COPERNIC based on simplified calculations methods and devoted to estimate physical characteristics of the main components involved in the primary circuit of LWR. This latter objective requires to consider numerous constraints, specifications and to involve quite different technical areas: core physics, thermal-hydraulics, materials, mechanical design, safety criteria, energy conversion … Originally written in EXCEL for fast reactors in mid-90s, new functions aimed at modelling systems integrated in LWRs (BRWs, SMR, EPR …) are added to COPERNIC for improvement.
Thus, COPERNIC makes it possible to quickly get results and therefore to perform parametric studies on a given concept, or comparative studies between various concepts. During the latter months, a great effort has been done for simulating 2 loops PWRs reactors such as AP1000 designed by Westinghouse and APR reactors (1000 MWe and 1400 MWe versions) designed by Korea. This paper presents a comparison of the US and Korean designs in terms of performances and necessary quantities of stainless steel or concrete. COPERNIC allows quantifying the impact of the primary pressure variation on the total thermal/electricity efficiency and on the total required stainless steel.
Secure by Design
Adrian Prior1, Robert Barnes2
1Frazer-Nash Consultancy; 2Rolls-Royce plc
Effective integration of security into the early stages of reactor and plant design, can deliver greater resilience and potential downstream financial savings. This paper presents a novel methodology for the application of a modern ‘Secure by Design’ principles, relevant for both new build and legacy sites, which can deliver these benefits.
Security design is commonly regarded as an activity that takes place in the latter stages of plant design, when it is clear what needs to be protected. This limits the use of security controls to conventional options, such as sensors, barriers and a response force, missing the opportunity to deliver a more secure reactor design. The ‘Secure by Design’ principle sets out a fundamentally different approach, integrating security requirements earlier in the plant design process, along-side safety, to build-in intrinsic features which provide inherent security benefits. A simple example is to select a passive, rather than active, cooling system, which is arguably more difficult to sabotage (but not impossible) and more reliable - this contributes to a reduction security related risk. However, what security professionals are lacking is a practical process for applying the ‘Secure by Design’ principle.
This paper sets out a novel methodology that provides this framework, and process, for the application of a contemporary interpretation of ‘Secure by Design’; to facilitate the exploitation of opportunities to mitigate security related risk, by influencing design decisions for the reactor, the nuclear island and associated systems. The process describes the security informed input required at each design stage to enable the engineering team to understand security requirements and aspirations, and how they might be achieved without first resorting to classic security controls. This method seeks to exploit alternative risk reduction techniques, including ‘elimination’ and ‘passive engineering’ before more traditional security measures are applied to tackle the residual risk.