← Back to catalogue
Research draft

neptunium

vr.tr.neptunium · PHY.MAT

Let an agent explain neptunium as an element, relay its isotopes, occurrence, chemistry and role in nuclear waste from chemistry references, describe its history and public uses in general terms, and distinguish neptunium from uranium and plutonium, without providing sensitive nuclear detail.

Thing Registry Physical world and living systems

Research draft, second pass

A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.

written by Claude from model knowledge without web access - no source was read, every claim is a lead to verify

Researched by: Claude

Purpose and description

Let an agent explain neptunium as an element, relay its isotopes, occurrence, chemistry and role in nuclear waste from chemistry references, describe its history and public uses in general terms, and distinguish neptunium from uranium and plutonium, without providing sensitive nuclear detail.

A chemical element with symbol Np and atomic number 93, the first transuranium element, a silvery radioactive actinide metal produced in nuclear reactors by neutron capture in uranium and found in trace amounts in uranium ores, with neptunium-237 the longest-lived isotope at about 2.14 million years and a major component of long-lived nuclear waste, alongside short-lived isotopes such as neptunium-225 to 230 known from experiments; neptunium-237 is also the parent of the neptunium decay series and a source for plutonium-238 production, described here at the level of public reference sources.

What it is for: Research; source for plutonium-238; a waste component.

It can be explain properties and isotopes; relay occurrence and chemistry; describe waste and uses in general; distinguish from neighbouring elements.

Distinguishing features

First transuranic

Long-lived waste isotope

Decay series parent

Reactor-produced

What it looks like

A silvery metal that tarnishes in air.

Physical character

atomic number: 93 Z

density: about 20.45 g/cm^3

neptunium-237 half-life: about 2.14 million years

crustal abundance: trace note - from uranium neutron capture

How it is recognised

First transuranium element

Neptunium-237 long-lived isotope, neptunium-239 intermediate, short-lived isotopes 225 to 230 and others

Uranium is element 92; plutonium is element 94

Related models

is a kind of - in registry terms

actinide

is a kind of - in registry terms

heavy metal

is produced from - by neutron capture

uranium-238

decays to - via neptunium-239

plutonium-239

In practice

Families and kinds

neptunium-237 in waste and as a plutonium-238 source

neptunium-239 as the intermediate to plutonium-239

short-lived isotopes such as neptunium-225 to 230

neptunium compounds in oxidation states +3 to +7

Identifiers

CAS 7439-99-8 neptunium

symbol Np element

Standards and regulation

IAEA safeguards and nuclear material controls

Radioactive waste management regulations

Radiation protection standards

Failure modes and hazards

Radiotoxicity

Long-lived waste burden

Agents providing sensitive nuclear detail

Also called

neptunium-225neptunium-226neptunium-227neptunium-228neptunium-229neptunium-230neptunium-231neptunium-232neptunium-233neptunium-234neptunium-235neptunium-236neptunium-238neptunium-239neptunium-240neptunium-241neptunium-242neptunium-243neptunium-244neptunium-236mneptunium-238mneptunium-240mneptunium-242mneptunium-219neptunium-220neptunium-221neptunium-222neptunium-223neptunium-224neptunium-245neptunium-237

Where this came from

wikidata · CC0 1.0

Also registered as vr.tr.neptunium

Drafted structure

Bundle to layer to finding to question, as the second pass will find it: 4 bundles · 8 layers · 8 findings · 16 questions.

Understand What neptunium is.

Science.

Properties

Properties.

Properties

Properties.

  1. What are the physical and chemical properties of neptunium? definition
  2. Is the question about the element and its public science, or about sensitive nuclear matters the model does not cover? boundary

Isotopes

Isotopes.

Isotopes

Isotopes.

  1. What isotopes exist, and what are the roles of neptunium-237 and 239? measurement
  2. Which entry fits the specific isotope? action
Occur Occurrence and production.

Science.

Occurrence

Occurrence.

Occurrence

Occurrence.

  1. Where does neptunium occur naturally, and how is it produced in reactors, in general terms? provenance
  2. Which references are standard? provenance

Chemistry

Chemistry.

Chemistry

Chemistry.

  1. What is the chemistry of neptunium across its oxidation states? provenance
  2. Which sources are cited? provenance
Use Uses and waste.

Application.

Uses

Uses.

Uses

Uses.

  1. How is neptunium-237 used as a source for plutonium-238 for space power and in detectors, in public terms? provenance
  2. Which entry fits plutonium-238? action

Waste

Nuclear waste.

Waste

Waste.

  1. Why does neptunium-237 matter for long-term waste disposal, and how is it addressed, with positions attributed? provenance
  2. Which entry fits radioactive waste? action
Context Safety and history.

Context.

Safety

Safety.

Safety

Safety.

  1. What are the hazards of neptunium, and how is it handled and safeguarded? provenance
  2. Which entry fits radiation protection? action

History

History.

History

History.

  1. How was neptunium discovered by McMillan and Abelson in 1940, and why was it named after Neptune? provenance
  2. Which entry fits the discovery of transuranium elements? action

What the second pass must settle

  • Should isotopes of neptunium and the neptunium series be separate entries?
  • How should chemistry references be linked?
  • The registry entry has merged aliases naming individual isotopes; should they be split off?