Wikipedia:Peer review/Plutonium/archive1

Plutonium

• A script has been used to generate a semi-automated review of the article for issues relating to grammar and house style; it can be found on the automated peer review page for January 2009.

This peer review discussion has been closed.
Article is FA now but there are some remaining comments leftover from the FAC that I'd like to address. To start this PR off, I have copied those remaining comments below. mav (talk) 01:29, 4 January 2009 (UTC)

Review by Headbomb

Physical

• Question, are allotropes and phases the same thing here?Headbomb {ταλκ κοντριβς – WP Physics} 05:51, 23 December 2008 (UTC)

• I think so, but it may be better to use "form" instead of "phase" when talking about different allotropes, so I implemented that. I also added "...following phase transitions from one allotropic form to another." to hopefully make it more clear. That particular fact comes from this sentence on page 294 of the cited ref: 3. The densities of the allotropes vary significantly, resulting in dramatic volume changes accompanying phase transitions. Although, "phase" in fact is commonly used in this context, it can be confusing for those who associate it solely with the classic solid-liquid-gas-plasma phases. --mav (talk) 02:19, 4 January 2009 (UTC)

Medical experimentation

• Details on the animal experiments would add a lot to this section

• Good point - but I couldn't find anything specific from a reliable source. Most of the animal stuff available refers to animals in context to the human experiments. Two more sentences added about the animal part: "Animal studies found that a few milligrams of plutonium per kilogram of tissue is a lethal dose." and "This was reduced to one microgram in July 1945 after animal studies found that the way plutonium distributed itself in bones was more dangerous than radium." --mav (talk) 02:19, 4 January 2009 (UTC)

Power source

• Tone down to "Is is still used to hear scuba suits?

• After looking closer, it appears that it was studied for use in scuba suits and a prototype was made and used, but I can't find any info on actual use beyond those studies. Sentence changed to: "Pu-238 was studied as way to provide supplemental heat to scuba diving suits." --mav (talk) 02:48, 4 January 2009 (UTC)

General remark

• Sometimes notes are placed before refs, other times they are after. I would consider place them all before.

• Article now is standardised on [1][note 1] format b/c the cite refers to the sentence it immediately follows while the note is for supplementary info (which should have its own ref inside the note). [note 1][1] may be interpreted as saying that the cite [1] also covers the note. Therefore, I think that the way the article now has it is better. --mav (talk) 02:57, 4 January 2009 (UTC)

I'd say I'd essentially support it as an FA, but I would like some clarification about phases and allotropes being the same thing or not. Maybe it's been addressed in the article already. The expanding on the animal experiments would be nice, but is not a deal-breaker IMO. Headbomb {ταλκ κοντριβς – WP Physics} 12:06, 29 December 2008 (UTC)

OK - I think I've addressed your concerns. Please take a look. --mav (talk) 03:12, 4 January 2009 (UTC)

Review by Nihiltres

• "These and other properties make the handling of plutonium dangerous and have led to a number of criticality accidents." This sentence needs to be revised: logical analysis reveals that the sentence could be construed as saying that "other properties […] have led to a number of criticality accidents", which is not exactly true. Specifying that it is the radioactivity that leads to criticality accidents would be better.

• Criticality accident mention moved from that sentence to the human radiation experiment sentence in lede. --mav (talk) 03:26, 4 January 2009 (UTC)

• "Fuel grade plutonium contains from 7 to less than 19% percent, and power reactor grade contains from 19% and greater Pu-240" Percent is doubled.

• Fixed. --mav (talk) 03:39, 4 January 2009 (UTC)

• "During World War II the U.S. government set-up the Manhattan Project, which was tasked with developing an atomic bomb." The phrase "set-up" up-sets me. :) Surely there's a more descriptive word that can be used here. It's also inconsistent with the nearby "Later, large 200 MW reactors were set up at the Hanford Site […]"…

• Changed to "established" and second sentence no longer exists. --mav (talk) 03:39, 4 January 2009 (UTC)

• "Mox fuel is used in […]" and "MOX fuel has been in use since […]": please make the capitalization consistent.

• Standardised on "MOX". --mav (talk) 03:39, 4 January 2009 (UTC)

• The last three sentences in the Flammability subsection of the Precautions section feel very choppy: in particular, the mention of the Rocky Flats fire seems to stick out. Rearranging this section for better flow would be advisable.

• Yikes - you are correct. Rocky Flats part moved to end and placed in ref note. I think it flows much better now. --mav (talk) 03:39, 4 January 2009 (UTC)

I think that the writing is overall pretty decent: let's fix up these little stumbles. :) {{Nihiltres|talk|log}} 04:06, 23 December 2008 (UTC)

I believe all these issues have now—that is, in this PR, as copied from the FAC—been fixed. Thanks. {{Nihiltres|talk|log}} 01:44, 5 January 2009 (UTC)

Review by Axl

From the lead section, paragraph 1: "When exposed to moist air, it expands up to 70% in volume and forms a powder that can spontaneously ignite." [Emphasis mine.] Is this really the elemental plutonium? Or is there a chemical reaction involved? From the "Flammability" section, it looks like this represents oxidation. Axl ¤ [Talk] 13:11, 26 December 2008 (UTC)

• You are correct. The sentence now reads: "When exposed to moist air, it forms oxides that expand the sample up to 70% in volume; which in turn flake off as a powder that can spontaneously ignite." --mav (talk) 19:50, 4 January 2009 (UTC)

  Thank you. Axl ¤ [Talk] 11:54, 5 January 2009 (UTC)

From "Characteristics", "Nuclear": "Plutonium is a radioactive actinide metal that, with uranium, is one of the few elements with one or more fissile isotopes." Why is uranium singled out as one of the few similar elements? Axl ¤ [Talk] 13:19, 26 December 2008 (UTC)

• That was badly worded. Changed to: "Plutonium is a radioactive actinide metal whose isotope, plutonium-239, is one of the three primary fissile isotopes (uranium-233 and uranium-235 are the other two)." --mav (talk) 20:37, 4 January 2009 (UTC)

  Thanks. Axl ¤ [Talk] 11:54, 5 January 2009 (UTC)

Why doesn't "Characteristics", "Nuclear" section describe the alpha decay of Pu-238? I added a brief comment right at the end of the section. From "Applications", "Power source", this property looks quite important. Axl ¤ [Talk] 14:03, 26 December 2008 (UTC)

• The point of that subsection is to introduce concepts related to the nuclear power and weapons industry. But a short mention of Pu-238 won't hurt - what you added seems sufficient. To avoid confusion I renamed that subsection to ===Nuclear fission===. Also, any atom that is hit with energetic enough particles will fission. So I added "easily" to the Pu-238 part. --mav (talk)

  I still think that this alpha decay process would benefit from a paragraph because the process is (or has been) used in a number of applications. Axl ¤ [Talk] 11:54, 5 January 2009 (UTC)

  Hence the space given to that isotope in the applications section. --mav (talk) 00:47, 6 January 2009 (UTC)

  Well, we disagree on this point. In my opinion, the alpha decay of Pu-238 is an important characteristic of plutonium, and deserves a place in the section entitled "Characteristics". Axl ¤ [Talk] 10:08, 6 January 2009 (UTC)

From "Characteristics", "Isotopes and synthesis", paragraph 1: "Because of its comparatively large half-life, minute amounts of Pu-244 can be found in nature." I think I know what the author means, but the sentence appears counter-intuitive. Axl ¤ [Talk] 13:30, 26 December 2008 (UTC)

• Hm. Seems fine to me, but to make it even more clear I changed it to: "Minute amounts of Pu-244 can be found in nature because it is has a comparatively long half-life and is formed as a decay product in uranium ores." --mav (talk) 21:42, 4 January 2009 (UTC)

  You've missed the point. "Minute" means "tiny". If the half-life is long, why is only a tiny amount present? With a long half-life, there should be a lot more. Axl ¤ [Talk] 11:59, 5 January 2009 (UTC)

  I see - "minor" added to the uranium decay product part. --mav (talk) 00:50, 6 January 2009 (UTC)

  It still doesn't seem quite right. How about "Trace amounts of Pu-244 occur naturally because it is formed as a minor decay product in uranium ores and it has a comparatively long half-life. Other isotopes do not occur naturally." ? Axl ¤ [Talk] 10:16, 6 January 2009 (UTC)

  Yes, that is better. But I think that a more fundamental problem is that sentence should be in the ===Occurrence=== subsection. I moved your wording (slightly modified) to there and tried to refactor that paragraph. I'm still not completely happy with the sentence & paragraph though but can't think of a better formulation right now... --mav (talk) 02:26, 8 January 2009 (UTC)

  After a few more copyedits, I'm now happy with the new paragraph. --mav (talk) 02:49, 8 January 2009 (UTC)

From "Characteristics", "Isotopes and synthesis", paragraph 1: "The primary decay modes before the most stable isotope, Pu-244, are spontaneous fission and α emission; the primary mode after is β emission. The primary decay products before Pu-244 are uranium and neptunium isotopes (neglecting the wide range of daughter nuclei created by fission processes), and the primary products after are americium isotopes." Does this mean that uranium and neptunium undergo spontaneous fission and alpha emission to form Pu-244? Pu-244 undergoes beta emission to form americium? This section could be clearer. Axl ¤ [Talk] 14:13, 26 December 2008 (UTC)

• Good point. I reorganised to group by before or after 244 instead of by decay product and mode. Text now reads: "The primary decay modes before the most stable isotope, Pu-244, are spontaneous fission and α emission; mostly forming uranium (92 protons) and neptunium (93 protons) isotopes as decay products (neglecting the wide range of daughter nuclei created by fission processes). The primary decay mode after Pu-244 is β emission; mostly forming americium (95 protons) isotopes as decay products." Proton numbers of decay products added to give the reader a better idea of what is going on. --mav (talk) 21:42, 4 January 2009 (UTC)

  I'm still not clear what the meaning of "before" and "after" are in this context. Axl ¤ [Talk] 12:09, 5 January 2009 (UTC)

  Hm. I thought that the preceding sentence, "The isotopes of plutonium range in mass number from 228 to 247", would be enough. Either way, "before" and "after" replaced by "of isotopes with mass numbers lower than" and "for isotopes with mass numbers higher than," respectively. --mav (talk) 00:47, 6 January 2009 (UTC)

  Okay, that wasn't clear to me before. Thanks for fixing it. Axl ¤ [Talk] 10:21, 6 January 2009 (UTC)

From "Characteristics", "Isotopes and synthesis", this equation does not appear to be correctly formatted:-

²³⁸U(d,2n)²³⁸Np → ²³⁸Pu + β⁻

Axl ¤ [Talk] 14:20, 26 December 2008 (UTC)

• Reference rechecked and its explanation. Both check out. That is apparently how one notes intermediate decay products in a chemical equation.... Exactly what is happening is already explained in the prose. --mav (talk) 21:42, 4 January 2009 (UTC)
• Better equation format found in German version. The article now gives:

$\mathrm {^{238}_{\ 92}U\ +\ _{1}^{2}D\ \longrightarrow \ _{\ 93}^{238}Np\ +\ 2\ _{0}^{1}n\quad ;\quad _{\ 93}^{238}Np\ {\xrightarrow[{2.117\ d}]{\beta ^{-}}}\ _{\ 94}^{238}Pu}$

Gota love the Germans. :) --mav (talk) 04:18, 5 January 2009 (UTC)

• Thanks, that's clear now. Axl ¤ [Talk] 12:09, 5 January 2009 (UTC)

From "History", "Production during the Manhattan Project", paragraph 4: "B, D and F were the initial reactors built at Hanford". I'm surprised that A, B and C weren't the initial reactors built. Axl ¤ [Talk] 15:00, 26 December 2008 (UTC)

• Oddly enough, the references I consulted did not mention those other reactors. But I don't think it is correct to assume they strictly followed an alphabetic progression; esp in regards to the specific task of producing plutonium. Besides, this article is about the element, not the Hanford Site, so I don't want to get bogged down with peripheral details like this. --mav (talk) 22:50, 4 January 2009 (UTC)

  Indeed today's main page featured article, "Hanford Site", describes the reactors in more detail. B, D & F is correct. {Although the naming of the reactors seems rather random.] Axl ¤ [Talk] 12:20, 5 January 2009 (UTC)

From "History", "Cold War use and waste": "The U.S. reactors at Hanford and the Savannah River Site in South Carolina produced 103,000 kg, and an estimated 170,000 kg of military-grade plutonium was produced in Russia. Each year about 20,000 kg of the element is still produced as a by-product of the nuclear power industry. As much as 1000 tonnes of plutonium may be in storage with more than 200 tonnes of that either inside or extracted from nuclear weapons." Why not use "tonnes" consistently throughout? Axl ¤ [Talk] 15:06, 26 December 2008 (UTC)

• Fixed. Reads better now. --mav (talk) 22:50, 4 January 2009 (UTC)

  Thanks. Axl ¤ [Talk] 12:24, 5 January 2009 (UTC)

From "History", "Cold War use and waste": "The glass consists of borosilicates mixed with as cadmium and gadolinium". The grammar is incorrect and I don't know what it should be. Axl ¤ [Talk] 21:59, 26 December 2008 (UTC)

• I'm far from an expert in grammar so I don't know what is wrong with the sentence... Is this better?: "The glass is made of borosilicates mixed with the powerful neutron absorbers cadmium and gadolinium." But then doesn't 'powerful neutron absorbers' scream for some hyphens? --mav (talk)

  Ah, I see now. The offending word in the original sentence is "as". Without that, the sentence makes sense. I'll change the article text. Axl ¤ [Talk] 12:26, 5 January 2009 (UTC)

From "History", "Cold War use and waste", is there a reference for the Yucca Mountain nuclear waste repository? Axl ¤ [Talk] 22:02, 26 December 2008 (UTC)

• Ref added. --mav (talk) 22:50, 4 January 2009 (UTC)

  Thanks. Axl ¤ [Talk] 12:15, 5 January 2009 (UTC)

The picture caption in "Applications", "Power source" reads "A pellet of plutonium-238, glowing due to blackbody radiation." However the article indicates that plutonium is silvery-white in colour. Is the pellet of Pu-238 really a black body? Axl ¤ [Talk] 22:22, 26 December 2008 (UTC)

• Ah hell - no way that can be correct. Changed to "alpha decay". --mav (talk)

  Are you sure that it's not due to pyrophoricity? Axl ¤ [Talk] 12:15, 5 January 2009 (UTC)

  Almost certainly due to alpha decay b/c the pellet is thermally isolated. But to be careful, I changed the caption to "A glowing pellet of ²³⁸PuO₂". --mav (talk) 00:35, 6 January 2009 (UTC)

  Okay, thanks. I see that you've changed the caption to indicate plutonium oxide rather than plutonium. Axl ¤ [Talk] 10:08, 6 January 2009 (UTC)

From "Precautions", "Toxicity": "The U.S. Department of Energy estimates the increase in lifetime cancer risk for inhaled plutonium as 3 × 10⁻⁸ pCi⁻¹.^[48]" Unfortunately I can't seem to view the Argonne National Laboratory's fact sheet. Can someone confirm that the fact sheet is still available? Wouldn't "sieverts" be more helpful than "curies"? I would like to review the validity of the cancer risk information. Axl ¤ [Talk] 22:39, 26 December 2008 (UTC)

• It is a PDF - I don't have any problem downloading it... I found better info in the cite and added that instead. The article now reads: "The U.S. Department of Energy estimates that the lifetime cancer risk for inhaling 5,000 plutonium particles, each about 3 microns wide, to be 1% over the background U.S. average." --mav (talk) 00:25, 5 January 2009 (UTC)

  Okay. I'll try looking for some more information. Axl ¤ [Talk] 12:31, 5 January 2009 (UTC)

From "Precautions", "Criticality potential": "Plutonium in solution is more likely to form a critical mass than the solid form due to moderation by the hydrogen in water." [Emphasis mine.] Is "moderation" a technical term? Axl ¤ [Talk] 22:45, 26 December 2008 (UTC)

Now linked to neutron moderator. --mav (talk) 00:25, 5 January 2009 (UTC)

• Okay, thanks. Axl ¤ [Talk] 12:40, 5 January 2009 (UTC)

Other reviews

Something to fix:

• "Partial exceptions include the refractory metals chromium, molybdenum, niobium, tantalum and tungsten, which, while soluble in liquid plutonium and insoluble or only slightly so in solid plutonium."

I'm not sure what this intends to say, but it's not a complete sentence. Please rewrite for clarity. Crystal whacker (talk) 22:39, 23 December 2008 (UTC)

• It looks like the writer(s) meant to say "are" instead of "and" on the second instance of the latter. Correcting that would make the sentence more clear, but the "or only slightly so" seems to be saying more "slightly soluble" than "slightly insoluble": this still needs work. If someone can confirm the facts (please), a suggestion for correction, based on my assumptions, would be "Partial exceptions include the refractory metals chromium, molybdenum, niobium, tantalum, and tungsten, which, while soluble in liquid plutonium, are insoluble or only slightly soluble in solid plutonium." {{Nihiltres|talk|log}} 23:16, 23 December 2008 (UTC)

• Somebody else changed that to: "Partial exceptions include the refractory metals chromium, molybdenum, niobium, tantalum and tungsten, which are soluble in liquid plutonium, but insoluble or only slightly soluble in solid plutonium." --mav (talk) 03:49, 4 January 2009 (UTC)

Because of its comparatively large half-life, minute amounts of Pu-244 can be found in nature. Is this true, given the age of the earth? Isn't it more likely that Pu-244 is formed from U-238, and its long half-life allows detectable amounts to build up? jimfbleak (talk) 13:37, 30 December 2008 (UTC)

• Text now reads: "Minute amounts of Pu-244 can be found in nature because it is has a comparatively long half-life and is formed as a decay product in uranium ores." Hope that helps. --mav (talk) 00:30, 5 January 2009 (UTC)

Looks excellent. < and > take a space after. Tony (talk) 15:49, 30 December 2008 (UTC)

• Thanks - fixed. --mav (talk) 00:30, 5 January 2009 (UTC)