10-06-2021-0338 - 4487/8-9,4490

 10-06-2021-0338 - 4487/8-9,4490

10-06-2021-0337 - Decay heat

 Decay heat is the heat released as a result of radioactive decay. This heat is produced as an effect of radiation on materials: the energy of the alpha, beta or gamma radiation is converted into the thermal movement of atoms.

Decay heat occurs naturally from decay of long-lived radioisotopes that are primordially present from the Earth's formation.

In nuclear reactor engineering, decay heat continues to be generated after the reactor has been shut down (see SCRAM and nuclear chain reactions) and power generation has been suspended. The decay of the short-lived radioisotopes^{[example needed]} created in fission continues at high power for a time after shut down. ^[1] The major source of heat production in a newly shut down reactor is due to the beta decay of new radioactive elements recently produced from fission fragments in the fission process.

Quantitatively, at the moment of reactor shutdown, decay heat from these radioactive sources is still 6.5% of the previous core power if the reactor has had a long and steady power history. About 1 hour after shutdown, the decay heat will be about 1.5% of the previous core power. After a day, the decay heat falls to 0.4%, and after a week, it will be only 0.2%.^[2] Because radioisotopes of all half life lengths are present in nuclear waste, enough decay heat continues to be produced in spent fuel rods to require them to spend a minimum of one year, and more typically 10 to 20 years, in a spent fuel pool of water before being further processed. However, the heat produced during this time is still only a small fraction (less than 10%) of the heat produced in the first week after shutdown.^[1]

If no cooling system is working to remove the decay heat from a crippled and newly shut down reactor, the decay heat may cause the core of the reactor to reach unsafe temperatures within a few hours or days, depending upon the type of core. These extreme temperatures can lead to minor fuel damage (e.g. a few fuel particle failures (0.1 to 0.5%) in a graphite-moderated, gas-cooled design^[3]) or even major core structural damage (meltdown) in a light water reactor^[4] or liquid metal fast reactor. Chemical species released from the damaged core material may lead to further explosive reactions (steam or hydrogen) which may further damage the reactor.^[5]

RTG pellet glowing red due to the heat generated by the radioactive decay of plutonium-238 dioxide, after a thermal isolation test.

https://en.wikipedia.org/wiki/Decay_heat

10-06-2021-0336 - void coefficient void coefficient of reactivity

 In nuclear engineering, the void coefficient (more properly called void coefficient of reactivity) is a number that can be used to estimate how much the reactivity of a nuclear reactor changes as voids (typically steam bubbles) form in the reactor moderator or coolant. Net reactivity in a reactor is the sum total of all these contributions, of which the void coefficient is but one. Reactors in which either the moderator or the coolant is a liquid typically will have a void coefficient value that is either negative (if the reactor is under-moderated) or positive (if the reactor is over-moderated). Reactors in which neither the moderator nor the coolant is a liquid (e.g., a graphite-moderated, gas-cooled reactor) will have a void coefficient value equal to zero. It is unclear how the definition of 'void' coefficient applies to reactors in which the moderator/coolant is neither liquid nor gas (supercritical water reactor).

https://en.wikipedia.org/wiki/Void_coefficient

10-06-2021-0333 - RBMK Reactor

 The RBMK (Russian: реактор большой мощности канальный, РБМК; reaktor bolshoy moshchnosti kanalnyy, "high-power channel-type reactor") is a class of graphite-moderated nuclear power reactor designed and built by the Soviet Union. The name refers to its unusual design where, instead of a large steel pressure vessel surrounding the entire core, the core is surrounded by a cylindrical annular steel tank inside a concrete vault and each fuel assembly is enclosed in an individual 8 cm diameter pipe (called a "channel") surrounded in graphite (which is in turn surrounded by the tank) which allows the flow of cooling water around the fuel.

The RBMK is an early Generation II reactor and the oldest commercial reactor design still in wide operation. Certain aspects of the original RBMK reactor design, such as the active removal of decay heat, the positive void coefficientproperties, the 4.5 m (14 ft 9 in) graphite displacer ends of the control rods^[3] and instability at low power levels, contributed to the 1986 Chernobyl disaster, in which an RBMK experienced an uncontrolled nuclear chain reaction, leading to a steam and hydrogen explosion, a large fire and subsequent core meltdown. Radioactivity was released over a large portion of Europe. The disaster prompted worldwide calls for the reactors to be completely decommissioned; however, there is still considerable reliance on RBMK facilities for power in Russia. Most of the flaws in the design of RBMK-1000 reactors were corrected after the Chernobyl accident and a dozen reactors have since been operating without any serious incidents for over thirty years.^[4] While nine RBMK blocks under construction were cancelled after the Chernobyl disaster, and the last of three remaining RBMK blocks at the Chernobyl Nuclear Power Plant was shut down in 2000, as of 2019 there were still 9 RBMK reactors and three small EGP-6 graphite moderated light-water reactorsoperating in Russia,^[1][5] though all have been retrofitted with a number of safety updates. Only two RBMK blocks were started after 1986: Ignalina-2 and Smolensk-3.

RBMK reactor class
View of the Smolensk Nuclear Power Plant site, with three operational RBMK-1000 reactors. A fourth reactor was cancelled before completion.
Generation	Generation II reactor
Reactor concept	Graphite-moderated light water-cooled reactor
Reactor line	RBMK (Reaktor Bolshoy Moshchnosti Kanalniy)
Reactor types	RBMK-1000 RBMK-1500 RBMKP-2400
Status	26 blocks: 9 operational 1 destroyed 9 cancelled 8 decommissioned 3 small EGP-6 graphite moderated BWR operational (as of December 2018)[1][2]
Main parameters of the reactor core
Fuel (fissile material)	235U (NU/SEU/LEU)
Fuel state	Solid
Neutron energy spectrum	Thermal
Primary control method	Control rods
Primary moderator	Graphite
Primary coolant	Liquid (light water)
Reactor usage
Primary use	Generation of electricity and production of weapon grade plutonium
Power (thermal)	RBMK-1000: 3,200 MWth RBMK-1500: 4,800 MWth RBMKP-2400: 6,500 MWth
Power (electric)	RBMK-1000: 1,000 MWe RBMK-1500: 1,500 MWe RBMKP-2400: 2,400 MWe

https://en.wikipedia.org/wiki/RBMK

10-05-2021-1119 - Cherylnoble Town Logos, Instagram, Flyer, etc.. drafting Draft 2021

 

above. changed the title

Let's first look at 3$3$ digit phone numbers to simplify. If the first digit is "locked" at 0$0$ only, we then have 10$10$ choices for the 2$2$nd digit and 10$10$ choices for the 3$3$rd digit, thus giving us 10$10$ x 10$10$ = 102${10}^2$ = 100$100$ possible phone numbers. Examples would be 000,001,012...010,011,012...090,091,092...099$000,001,\mathrm{012...}010,011,\mathrm{012...090},091,\mathrm{092...099}$

For 10$10$ digit phone numbers with the first digit "locked" at 0$0$ it is similar except it would be 109${10}^9$ = 1,000,000,000$1,000,000,000$ = 1$1$ billion.

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edited Nov 17 '14 at 10:44

answered Nov 17 '14 at 10:39

David

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https://math.stackexchange.com/questions/1025767/number-of-different-possible-permutations-of-a-telephone-number

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