ENCAPSULATED NUCLEAR HEAT SOURCE REACTORS FOR ENERGY SECURITY

A spectrum of Encapsulated Nuclear Heat Source (ENHS) reactors have been conceptually designed over the last few years [1-10]; they span a power range from less than 100 MWth to over 200 MWth and consider a number of coolants and fuel types. Common features of all these designs include very long life cores \u2013 approaching or exceeding 20 effective full power years; nearly zero burnup reactivity swing; natural circulation; superb safety; autonomous load following capability; no on-site refueling; simplicity of operation and maintenance. These features make the ENHS and the like reactors of particular interest for developing countries because of the following reasons: they can provide (a) energy to communities not connected to a central electricity grid even in countries having limited technological infrastructure; (b) energy security with minimum risk of proliferation. Following a brief description of the reference ENHS reactor design (Sec. 2) we\u2019ll elaborate on the unique features of these reactors and discuss how these features could make these reactors of particular interest for developing countries (Sec. 3). A partial summary of different ENHS design options developed so far is provided in Section 4; it considers only Pb-Bi cooled uniform fuel core designs

ENCAPSULATED NUCLEAR HEAT SOURCE REACTORS FOR ENERGY SECURITY

A spectrum of Encapsulated Nuclear Heat Source (ENHS) reactors have been conceptually designed over the last few years [1-10]; they span a power range from less than 100 MW th to over 200 MW th and consider a number of coolants and fuel types. Common features of all these designs include very long life cores -approaching or exceeding 20 effective full power years; nearly zero burnup reactivity swing; natural circulation; superb safety; autonomous load following capability; no on-site refueling; simplicity of operation and maintenance. These features make the ENHS and the like reactors of particular interest for developing countries because of the following reasons: they can provide (a) energy to communities not connected to a central electricity grid even in countries having limited technological infrastructure; (b) energy security with minimum risk of proliferation. Following a brief description of the reference ENHS reactor design (Sec. 2) we'll elaborate on the unique features of these reactors and discuss how these features could make these reactors of particular interest for developing countries (Sec. 3). A partial summary of different ENHS design options developed so far is provided in Section 4; it considers only Pb-Bi cooled uniform fuel core designs. Reference ENHS Reactor The design features of the ENHS reactor include the following: • A small modular reactor; nominal power level is 125 MW th • There are no fuel assemblies in the core; each fuel rod is anchored in the factory to the grid plate • Nearly constant fissile fuel content and neutron multiplication factor; hence, very small excess reactivity built-in and very simple reactor control system that requires adjustment for burn-up only once every few years • Nearly constant power density shape across the core throughout its life • There are no pumps or valves in the primary and secondary coolant loops. The coolants flow by natural circulation • The natural circulation results in passive load following capability and autonomous control. It also makes loss-of-flow accidents inconceivable • There are no special decay heat removal systems other than a Reactor Vessel Air-Cooling System (RVACS) that uses natural air draft for the heat sink • As all structural components exposed to neutrons are disposed of with the ENHS module once in more than 20 years, the ENHS reactor lifetime might exceed 100 years. Figures 1 and 2 show simplified schematic views of the ENHS reactor. The reference ENHS reactor has two coolant circuits, both being of a pool type; the primary coolant circulates inside the ENHS module while the secondary coolant circulates in the pool the ENHS module is inserted in. The two coolant

Antiplasmodial benzophenones from the trunk latex of Moronobea coccinea (Clusiaceae)

In an effort to find antimalarial drugs, a systematic in vitro evaluation on a chloroquine-resistant strain of Plasmodium falciparum (FcB1) was undertaken on sixty plant extracts collected in French Guiana. The methanol extract obtained from the latex of Moronobea coccinea exhibited a strong antiplasmodial activity (95% at 10 mu g/ml). The phytochemical investigation of this extract led to the isolation of eleven polycyclic polyprenylated acylphloroglucinols (PPAPs), from which eight showed potent antiplasmodial activity with IC50 ranged from 3.3 mu M to 37.2 mu M

Pharmacomodulation on the 3-acetylursolic acid skeleton: Design, synthesis, and biological evaluation of novel N-{3-[4-(3-aminopropyl)piperazinyl]propyl}-3-O-acetylursolamide derivatives as antimalarial agents

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