A Green Road Blog 

Isotope

Half-life (yr) x 10 to total decay into another element, usually also radioactive. The longer the half life, the more one has to multiply to get the longer half life total decay time. This is what is present in nuclear plant melt downs and after nuclear bomb explosions or accidental melt downs.

Holmium-166m - 1,200 x 10 = 12,000 years total

Berkelium-247 -  1,380 x 10 = 13,000 years total

Radium-226  - 1,600 x 10 = 16,000 years total

Molybdenum-93 - 4,000 x 10 = 40,000 years total

Holmium-153 - 4,570 x 10 = 45,000 years total

Curium-246 - 4,730 x 10 = 47,000 years total

Carbon-14 - 5,730 x 10 = 57,000 years total

Plutonium-240 - 6,563 x 10 = 65,000 years total

Thorium-229 - 7,340 x 10 = 73,000 years total

Americium-243 - 7,370 x 10 = 73,000 years total

Curium-245 - 8,500 x 10 = 85,000 years total

Curium-250 - 9,000 x 10 = 90,000 years total

Tin-126 - 10,000 x 10 = 100,000 years total

Iodine-129 - 15,700 x 10 = 157,000 years total

Niobium-94 - 20,300 x 10 = 230,000 years total

Plutonium-239 - 24,110 x 10 = 240,000 years total

Proactinium-231 - 32,760 x 10 = 327,000 years total

Lead-202 - 52,500 x 10 = 537,000 years total

Lanthanium-137 - 60,000 x 10 = 600,000 years total

Thorium-230 - 75,380 x 20 = 750,000 years total

Nickel-59 - 76,000 x 20 = 1,520,000 years total

Thorium-230 - 77,000 x 20 = 1,540,000 years total

Calcium-41 - 103,000 x 20 = 2,060,000 years

Neptunium-236 - 154,000 x 20 = 3,080,000 years

Uranium-233 - 159,200 x 20 = 3,184,000 years

Rhenium-186m - 200,000 x 20 = 4,000,000 years

Technetium-99 - 211,000 x 20 = 4,220,000 years

Krypton-81 - 229,000 x 20 = 4,580,000 years

Uranium-234 - 245,500 x 20 = 4,910,000 years

Chlorine-36 - 301,000 x 20 = 6.000,000 years

Curium-248 - 340,000 x 20 = 6,800,000 years

Bismuth-208 - 368,000 x 20 = 7,360,000 years

Plutonium-242 - 373,300 x 20 = 7,466,000 years total

Aluminum-26 - 717,000 x 20 = 14,340,000 years total

Selenium-79 - 1,130,000 x 20 = 22,600,000 years total

Iron-60 - 1,500,000 x 20 = years total

Beryllium-10 - 1,510,000 x 20 = years total

Zircon-93 - 1,530,000 x 20 =  years total

Curium-247 - 1,560,000 x 20 =   years total

Gadolinium-150 - 1,790,000 x 20 =   years total

Neptunium-237 - 2,144,000 x 20 =  years total

Cesium-135 - 2,300,000 x 20 =   years total

Technetium-96 - 2,600,000 x 20 =   years total

Dysprosium-154 - 3,000,000 x 20 =   years total

Bismuth-310m - 3,040,000 x 20 = years total

Mietnerium-53 - 3,740,000 x 20 =   years total

Technetium-98 - 4,200,000 x 20 =   years total

Palladium-107 - 6,500,000 x 20 =   years total

Hafnium-182 - 9,000,000 x 20 =   years total

Lead-205 - 15,300,000 x 20 =   years total

Curium-247 - 15,600,000 x 20 =  years total

Uranium-236 - 23,420,000 x 20 =   years total

Niobium-92 - 34,700,000 x 20 =   years total

Plutonium-244 - 80,800,000 x 20 =   years total

Samarium-146 - 103,000,000 x 20 =   years total

Uranium-236 - 234,200,000 x 20 =  total years

Uranium-235 - 703,800,000 x 20 =  total years

Potassium-40 - 1,280,000,000 x 20 =  total years

Uranium-238 - 4,468,000,000 x 20 =  total years

Rubidium-87 - 4,750,000,000 x 20 =  total years

Thorium-232 - 14,100,000,000 x 20 =  total years

Lutetium-176 - 37,800,000,000 x 20 =  total years

Rhenium-187 - 43,500,000,000 x 20 =  total years

Lanthanium-138 - 105,000,000,000 x 20 =  total years

Samarium-147 - 106,000,000,000 x 20 =  total years

Platinum-190 - 650,000,000,000 x 20 =  total years

Tellurium-123 - 10,000,000,000,000 x 20 =  total years

Osmium-184 - 560,000,000,000,000 x 20 =  total years

Gadolinium-152 - 1,000,000,000,000,000 x 20 =  total years

Tantalum-180m - 1,000,000,000,000,000 x 20 =  total years

Xenon-124 - 100,000,000,000,000 x 20 =  total years

Indium-115 - 400,000,000,000,000 x 20 =  total years

Zinc-70 - 5,000,000,000,000,000 x 20 =  total years

Hafnium-174 - 2,000,000,000,000,000 x 20 =  total years

Osmium-186 - 2,000,000,000,000,000 x 20 =  total years

Samarium-149 - 2,000,000,000,000,000 x 20 =  total years

Neodymium-144 - 2,000,000,000,000,000 x 20 =  total years

Samarium-148 - 7, 000,000,000,000,000 x 20 =  140, 000,000,000,000,000 total years

Cadmium-113 - 8,000,000,000,000,000 x 20 = 1,600,000,000,000,000,000  total years

Cerium-142 - 50,000,000,000,000,000 x 20 =  total years

Tungsten-183 - 100,000,000,000,000,000 x 20 =  total years

Vanadium-50 - 100,000,000,000,000,000 x 20 =  total years

Lead-204 - 100,000,000,000,000,000 x 20 =  total years

Chromium-50 - 100,000,000,000,000,000 x 20 =  total years

Tungsten-184 - 300,000,000,000,000,000 x 20 =  total years

Calcium-48 - 6,000,000,000,000,000,000 x 20 =  total years

Molybdenum-100 - 10,000,000,000,000,000,000 x 20 =  total years

Neodynium-150 - 10,000,000,000,000,000,000 x 20 =  total years

Zircon-96 - 40,000,000,000,000,000,000 x 20 =  total years

Selenium-82 - 100,000,000,000,000,000,000 x 20 =  total years

Tellurium-130 - 800,000,000,000,000,000,000 x 20 =  total years

Xenon-136 - 2,000,000,000,000,000,000,000 x 20 =  total years

Tellurium-128 - 2,000,000,000,000,000,000,000,000 x 20 =  total years

Sources:
http://ie.lbl.gov/toi/nucSearch.asp
http://www.webelements.com/
http://www.blackcatsystems.com/science/natRadiation.html
Serway et al. 1997, "Modern Physics"

Nuclear Power, Radiation, and Disease

www.helencaldicott.com/chapter3.pdf