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Plutonium-238 (238 Pu or Pu-238) is a radioactive isotope of plutonium that has a half-life of 87.7 years. Plutonium-238 is a very powerful alpha emitter ; as alpha particles are easily blocked, this makes the plutonium-238 isotope suitable for usage in radioisotope thermoelectric generators (RTGs) and radioisotope heater units .
Numismatic Guaranty Company (NGC) is an international third-party coin grading and certification service based in Sarasota, Florida. It has certified more than 60 million coins. NGC certification consists of authentication, grading, attribution, and encapsulation in clear plastic holders. NGC is a subsidiary of Certified Collectibles Group (CCG ...
CACCoin.com. Certified Acceptance Corporation (CAC) is a Far Hills, New Jersey third-party coin certification company started in 2007 by coin dealer John Albanese. The firm evaluates certain numismatically valuable U.S. coins already certified by Numismatic Guaranty Corporation (NGC) or Professional Coin Grading Service (PCGS). [1][2]
Coin grading. Coin grading[1] is the process of determining the grade or condition of a coin, one of the key factors in determining its collectible value. A coin's grade is generally determined by six criteria: strike, preservation, luster, color, attractiveness, and occasionally the country/state in which it was minted.
Professional Coin Grading Service (PCGS) is an American third-party coin grading, authentication, attribution, and encapsulation service founded in 1985. The intent of its seven founding dealers, including the firm's former president David Hall, was to standardize grading. [4][5] The firm has divisions in Europe and Asia, and is owned by parent ...
U-232 hazards, a result of its highly radioactive decay products such as thallium-208, are significant even at 5 parts per million. Implosion nuclear weapons require U-232 levels below 50 PPM (above which the U-233 is considered "low grade"; cf. "Standard weapon grade plutonium requires a Pu-240 content of no more than 6.5
International Coin Certification Service (ICCS) is a Canadian third-party coin certification company located in Toronto, Ontario. [1][2] ICCS certification consists of grading, authentication, grade qualification, variety attribution, and other determinations. ICCS grades most world coins but is particularly known for grading Canadian dollars. [3]
Reactor-grade plutonium. Reactor-grade plutonium (RGPu)[1][2] is the isotopic grade of plutonium that is found in spent nuclear fuel after the uranium-235 primary fuel that a nuclear power reactor uses has burnt up. The uranium-238 from which most of the plutonium isotopes derive by neutron capture is found along with the U-235 in the low ...