Systems engineering introduces the holistic approach to system development that combines all interrelated disciplines to achieve an engineered product. Small modular reactors are reactors with an equivalent electric power of less than 300 MW.
This paper presents concept development of a barge mounted SMR to operate in a safe and secure way considering the available technologies. The paper adopts a needs driven approach where the needs of the customer are analyzed and various options to solve the aspirations are explored. The systems engineering approach encompasses both technical and management processes critical for decision making amongst the evaluated candidates solutions.
The concept development process is important in developing new systems or advancing improvement on the existing systems. The concept development process consists of the (a) Needs analysis (b) Concept Exploration (c) Concept definition
The trade- off matrix method is used to come up with best alternative solution to make a choice of Barge- mounted SMR.
The SMRs development allows for incremental construction which reduces significantly the capital at risk compared to large conventional nuclear power plants. The aim of SMR is to achieve enhanced safety and improved economics. The Initiation of a new system development generally comes from the fact that the counties are experiencing frequent power interruptions and electricity access rate still low. The problem of lack of clean water for use in households and irrigation has led to the need to utilize the SMR for sea water desalination and power generation.
This is the second phase of concept development. It has the following stages;
Formulation of performance requirement
The performance requirements are formulated as follows; barge mobility to be 30km/h, seismic condition of greater than 0.3 g, desalination capacity of 50000 ton/day, containment wall of 1.5m thickness, core damage frequency of above 10-6 and power output of between 50MW to 300MW.
This is the final phase of concept development process and the input to this phase is the set of output of concept exploration phase (validated performance requirements).
In concept definition, selection is based on the program risks that could result from a number of sources namely; (1) un-proven technology (2) Difficulty in performance requirements (3) Severe environment (4) In-adequate funding or staffing and (5) un-duly short schedule. These factors are used as controls and enabling mechanisms at each stage of concept definition phase. The predecessor SMR is used as a guiding concept for selection of the suitable BM SMR solution for this project.
The sea water is received from the environment and evaporated through the evaporator. The evaporated water then undergoes filtration in order to remove any impurities and the end product is fresh water.
Trade Off analysis- Select Concept
In order to select the best BM SMR candidate solution for the listed requirements, trade off analysis is done on the available SMR alternatives. The trade- off matrix method is used to come up with best alternative solution for the user to make a choice.
The tradeoff matrix compares the rating of five candidates conceptual SMRs with respect to five evaluation criteria: mobility, seismic conditions, power output, desalination capacity and the cost.
On a scale of 0-5, the maximum of 5 was assigned to seismic withstand condition due to its critical to safety. The next highest 4 was allocated to power output since it has a direct impact on the plant area required. Mobility was assigned 3 because it is not very critical but required for transportation. Desalination tank capacity was assigned value 2 because it is an auxiliary requirement for the system.
Comparing the weighted sums of the SMRs under consideration, KLT-40S scored significantly higher than the other designs. KLT-40S scored satisfactory in all the four performance criteria. It is worth noting that the cost was not considered in the criteria since the exact cost of each SMR is prorated per MW produced. RIT model scored satisfactory in the seismic category and average in the three criteria and thus ranked second with 58 points while SMART also rated score 58 with the satisfaction of seismic and output power criteria.
The result shows that KLT-40S architecture concept has the highest weighted sum and therefore should be selected as the most preferred BM SMR for the Kenya’s desalination project.