Reactor coolant system
ABSTRACT
This paper pursues to review the literature regarding the functioning and the significance of the separate parts or constituents of the RCS. Moreover, this paper discusses the research on the significant parts of the system, which are the Steam generator, rotating coolant pump, and the Hot Leg piping, as well as the various precautions that operators must observe while operating the Reactor Coolant System. However, the system mainly comprises a set of three identical loops which are connected in parallel to a reactor vessel, to facilitate the transfer of heat. However, each of the three circles contains a rotating pump and a steam generator. Other components encompassed in the system include pressurizer break reservoir, pressurizer, joining tubing, and arrangement essential for functional regulating and shield.
INTRODUCTION
The Reactor Coolant System fundamentally transmits heat, manufactured in the core connected to the steam producers where the vapor for driving the turbine producer is produced. Borated de-mineralized trivial water is rotated at the movement rate and hotness, which is reliable with attaining the reactor primary thermal-hydraulic enactment (Memmott et al., 2017). Additionally, the water serves as a neutron mediator and indicator, and as a fluid for the absorber of neutrons used in organic shim regulation.
The RCS also offers a frontier for containing the coolant under the working pressure and temperature settings. It serves a very substantial role in confining a harmful solid and limiting to satisfactory standards its discharge to the subordinate and supplementary portions of the system entity under situations of either standard or nonstandard operations of the reactor (Wang et al., 2020). However, during the transient RCS, the system’s heat capacity weakens thermal transients produced by the basic or extracted by the vapor producers. The RCS also billets fluctuations in the coolant capacity within the safeguard scheme benchmarks.
However, the thermal-hydraulic properties result in losses of energy to the RCS because pumping of the coolant is also declined to an acceptable assortment of the apathy of the vessel coolant propels. The outline of the RCS safeguards that ordinary movement proficiency ensures a forfeiture of movement to certify cool-down deprived of causing overheat of the core (Heo & Oh, 2018). Necessarily, part of the piping of the RCS is rummaged by the Reserve Core Refrigeration Scheme to supply refrigerating water to the core throughout an accident of losing coolant.
However, the following discussion evaluates the literature from various journal articles, mainly based on the working of the RCS, the significance of the steam producer, the tubing and the coolant drive, as well as safety precautions that operators should check in the event of operating an RCS which is risky to breakdown or even can cause harm to workers.
LITERATURE REVIEW
The Reactor Coolant System is regarded as very substantial with reverence to its welfare purpose in shielding the well-being and protection of the community (Jeltsov et al., 2018). However, the design of the RCS and components of reactor facilities which are very fundamental in ensuring deterrence or extenuation of the associated concerns like atomic calamities, which might result in an unjust threat to healthiness and protection of both the community and the operators. Such possible risks are identified. Then design, fabrication, and inspection techniques are identified and executed in conformity to the standard codes to assure applicability of standards and test procedures to confirm that all possible risks are catered for.
Wang et al. (2020) exemplify various forms of nuclear accidents associated with the failure of the reactor coolant pump, especially when the pump is excessively loaded during operation. However, operators are advised to ensure they are conversant with safety operations like fluctuation of pressure, rate of coolant flow since it hinders the working of the rotor, or even breaking the rotor down.
The study by Xu et al. (2018) focuses on the significance of the coolant drives and the steam producer, and how they impact the functionality of the entire RCS plant. Precisely, the authors underscore the flow of the coolant into the coolant pump, which is interconnected to the steam-generating simulator. Additionally, this study exemplifies that the flow structures of the device coolant greatly influences the functionality of the system since it determines the rotational speed, hence creates pressure which maintains uniform vibrations since pulsations are very negligible.
Memmott et al., (2017) clarified that nuclear power is renowned for providing clean and affordable electricity and added that the effectiveness of the RCS plant is determined by the compliance with the basic design standards. However, they recommend that small prefabricated reactors are preferable because they create substantial protection benefits by disregarding large bore piping, which is associated with the slow cooling effect of the reactor coolant. Furthermore, this study focuses on the basic designs of RCS components like coolant drives, thermal exchangers, and the device compression container. The essence of this study is to offer an integrated model of the RCS plant components to enhance the principal coolant scheme since it defines the functioning of the entire plant.
Heo & Oh (2018) particularly evaluates the draining piping connected to the steam generator, which removes the coolant which remains after the operation of the plant. Moreover, they mentioned that the drain pipe serves as the pressure frontier amid the secondary and primary coolant system to prevent leakages of the coolant. However, the pipe should be designed to absorb vibrations resulting from the various parts of the plant such that it cannot break or leak any coolant during the working.
Jeltsov et al., (2018) declare that leakages and ruptures in the steam generator are a major safety issue in the working of the RCS because water or coolant is injected from the secondary side of high to the primary side which has low pressure. However, the major problem associated with this is that there may be void transport to the core; hence the performance of the reactor like heat transfer is deteriorated. This depicts that the RCS requires regular servicing to ensure that there are no leakages in the steam generator to improve effectiveness and minimize accidents.
According to the study by Hastuti et al., (2018), the cause of most RCS-related accidents is greatly interlinked with the design process because when the designing standards were observed keenly, the evaluation of the risks which are exactly the accidents in future. Moreover, this study declared that reactivity insertion accident results when one inadvertently withdraws all fuel at a normal rate of operation. However, the basis of this accident shows that an operator interferes with the fuel rod detracts from the normal operation, and an accident may occur. The summary of this study depicts that when the designing of an RCS follows the standards, and when operators are equipped with the basic operational skills, possibilities of accidents are evaded. Moreover, it clarifies that operators should never interfere with the fuel rod when the system is running.
CONCLUSION
In summary, the reviewed literature portrays that all safety precautions of operating the Reactor Coolant System are all interlinked to design standards for each component, particularly the major like steam generators, coolant pumps, and piping connecting the two parts. Moreover, operators must understand the standard conditions of the nuclear plant, especially temperature and pressure, to ensure that they maintain the system pressure to avoid breaking the piping carrying coolant (Hastuti et al., 2018). Regular servicing of the steam generator is also recommended so that any possible leakages of the coolan may be identified and serviced since such leakages pose a risk to operators.
Further research is required to evaluate the corrosion rate of the material used to manufacture the components of the RCS, particularly the pipes which drain the coolants. This is because new methods of preventing rusting or corrosion of the components will minimize risks of leakages, which pose risks of accidents to operators.
References
Hastuti, E. P., Tukiran, S., Widodo, S., & Sudarmono. (2018). Abnormal control rod withdrawal analysis for innovative research reactor using PARET-ANL codes. Kerntechnik, 83(2), 96-105.
Heo, Y. H. & Oh, S. H. (2018). Design modification and shaking table test of the drain pipes of the steam generator for vibration reduction. Nuclear Engineering and Design, 340, 68-72.
Jeltsov, M., Villanueva, W., & Kudinov, P. (2018). Steam generator leakage in the lead cooled fast reactors: Modeling of void transport to the core. Nuclear Engineering and Design, 328, 255-265.
Memmott, M. J., Manera, A., Boyack, J., Pacheco, S., Wang, M., & Petrovic, B. (2017). The primary reactor coolant system concept of the integral, inherently-safe light water reactor. Annals of Nuclear Energy, 100, 53-67.
Wang, X., Lu, Y., Zhu, R., Fu, Q., Chen, Y., & Zhong, W. (2020). Experimental study on transient characteristics of reactor coolant pump under rotor seizure accident—Annals of Nuclear Energy, 136, 107039.
Xu, R., Long, Y., & Wang, D. (2018). Effects of rotating speed on the unsteady pressure pulsation of reactor coolant pumps with the steam-generator simulator. Nuclear Engineering and Design, 333, 25-44.