Recent content by Andrew1949

So, calculating A = 0.5 x NA / t1/2 would give us the mean activity from t = 0 (present time) up to t = t1/2 ..., because during the length time t1/2, exactly 0.5 x NA atoms decay. But calculating A = NA x ln(2) / t1/2 will give the instant activity, when the number of atoms involved is the...

Activity (in Bq) of 1 mol of a radionuclide is given by formula: A = NA x ln(2) / t1/2 = 0.693 x NA / t1/2 where NA is Avogadro number and t1/2 the half-life (in seconds) Why don't we use simply A = 0.5 x NA / t1/2 ? After all, t1/2 means that, after that time, half of atoms will have decayed...

Well, I couldn't find normal ranges for blood lithium for a "normal" person ("Mr/Ms Everyone") but I accept that 0.8 mmol/L would be a real upper limit for that normal person, and something not to be done routinely when safer alternatives exist. So, bye bye lithium. On the other hand, it seems...

About toxicity of lithium : If I do not make mistakes, the molar mass of KI is 39.10 + 126.90 = 166 g/mol. Giving 130 mg of KI means giving 130 x E-3 / 166 = 7.83 x E-4 mol of KI and so, the same amount of iodine. I then understand that 7.83 x E-4 mol of iodine are recommended for blocking...

Hi, Does anyone know the reason why we use potassium iodide for thyroid protection in case of nuclear accidental event, and not sodium iodide, or lithium iodide ? (as alkali metals can give away one electron) Thanks.

That's perfect. That's what I was looking for.

"There may be several pathways." For sure ! But no one is clearly described... In this table, as an example "https://www-nds.iaea.org/wimsd/fpyield.htm#T2", I-131 is not listed as a possible direct fission product of U-235. So, I-131 does appear, of course, but the chain of reactions leading to...

Because everybody says that I131 is formed in nuclear reactors and is hazardous (so many exercises for students in physics are about Chernobyl or Fukushima and include calculations on Cesium 137 or Iodine 131), but noboby seems to know how I131 is formed in the reactors... It amazes me. And I do...

Hello Andrew, Sure, I131 doesn't come from U235 by decay. But the question still is that I have no example of nuclear reaction leading to I131. It could be U235 -> I131 + Xx + n neutrons; but then, what is the X element? ; what is the number n? Giving that we must have : 235 = 131 + x + n. It...

Hello, It seems everybody knows that iodine-131 is produced in nuclear reactors, but so far, I couldn't find any example of nuclear reactions starting with U-235 and leading to I-131...! Directly, undirectly, going through other fission products, going through beta decay... Nothing. I mean...