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Guilherme Mazui

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What is the Difference Between PWR and BWR?

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Pressurized Water Reactors (PWRs) and Boiling Water Reactors (BWRs) are both types of Light Water Reactors (LWRs) that use ordinary water as a coolant and neutron moderator. However, there are key differences between the two:

  1. Steam Generation: In a PWR, steam is generated indirectly by transferring heat from the primary reactor coolant to a secondary circuit, where steam is produced for the turbine. In contrast, a BWR produces steam directly by boiling the water coolant inside the reactor core.
  2. Coolant Circuits: A PWR employs two separate water circuits, a primary one and a secondary one, for steam generation. On the other hand, a BWR uses a single water circuit, which serves as both a coolant and a steam generator.
  3. Pressure: PWRs operate at a higher pressure compared to BWRs. This difference in pressure affects the method of steam production and the reactor's overall design.
  4. Turbine Process: In a PWR, steam and water are separated before entering the turbine, while in a BWR, the steam and water mixture directly enters the turbine. This results in radioactive steam being produced in a BWR, which is different from a PWR.

Both PWRs and BWRs are widely used in the production of electric power, with 69 out of 104 commercial nuclear power plants in the United States being LWRs as of 2016.

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  • What is the Difference Between PWR and BWR?
  • Comparative Table: PWR vs BWR

    • Comparative Table: PWR vs BWR

    Here is a table comparing the differences between Pressurized Water Reactors (PWR) and Boiling Water Reactors (BWR):

    Feature Pressurized Water Reactor (PWR) Boiling Water Reactor (BWR)
    Steam Generation Indirectly, using two water circuits Directly, using a single water circuit
    Steam Pressure High-pressure steam in a closed loop No separate steam generator system
    Water Circulation Primary and secondary water circuits Single water circuit
    Reactor Heat Heat is transferred to the secondary circuit by the steam generator Reactor core heats water, which turns to steam and drives a steam turbine
    Cooling Process Steam is condensed back into water and recycled after driving the turbine Steam and water mixture is cooled in the condenser coolant system, then returned to the steam generator
    Turbine Process Steam from the primary water circuit turns the turbine Steam from the reactor core drives the turbine
    Type of Coolant Both PWR and BWR use light water or normal water (H2O) as the coolant Both PWR and BWR use ordinary water to cool and heat the nuclear fuel
    Type of Moderator Both PWR and BWR use normal water (H2O) as the moderator Both PWR and BWR use the same type of moderator
    Fuel Enrichment Both PWR and BWR require 3-5% enriched uranium fuel Both PWR and BWR use comparable nuclear fuel
    Containment Both PWR and BWR have a containment vessel Both PWR and BWR have a similar general structure

    Both PWR and BWR reactors employ nuclear fission to generate thermal energy, which in turn is utilized to drive a turbine for generating electricity. They are both thermal reactors, requiring 3-5% enriched uranium fuel and normal water or light water as moderator, coolant, and working fluid. However, the main difference between the two lies in the process of steam generation: PWR generates steam indirectly using two water circuits, while BWR produces steam directly using a single water circuit. This difference results in varying steam pressure, water circulation, reactor heat, and turbine processes between the two reactor types.

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    Guilherme Mazui

    Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.