# 2. Depletion Chain – chain.xml¶

A depletion chain file has a <depletion_chain> root element with one or more <nuclide> child elements. The decay, reaction, and fission product data for each nuclide appears as child elements of <nuclide>.

## 2.1. <nuclide> Element¶

The <nuclide> element contains information on the decay modes, reactions, and fission product yields for a given nuclide in the depletion chain. This element may have the following attributes:

name

Name of the nuclide

half_life

Half-life of the nuclide in [s]

decay_modes

Number of decay modes present

decay_energy

Decay energy released in [eV]

reactions

Number of reactions present

For each decay mode, a <decay> Element appears as a child of <nuclide>. For each reaction present, a <reaction> Element appears as a child of <nuclide>. If the nuclide is fissionable, a <neutron_fission_yields> Element appears as well.

## 2.2. <decay> Element¶

The <decay> element represents a single decay mode and has the following attributes:

type

The type of the decay, e.g. ‘ec/beta+’

target

The daughter nuclide produced from the decay

branching_ratio

The branching ratio for this decay mode

## 2.3. <reaction> Element¶

The <reaction> element represents a single transmutation reaction. This element has the following attributes:

type

The type of the reaction, e.g., ‘(n,gamma)’

Q

The Q value of the reaction in [eV]

target

The nuclide produced in the reaction (absent if the type is ‘fission’)

branching_ratio

The branching ratio for the reaction

## 2.4. <neutron_fission_yields> Element¶

The <neutron_fission_yields> element provides yields of fission products for fissionable nuclides. Normally, it has the follow sub-elements:

energies

Energies in [eV] at which yields for products are tabulated

fission_yields

Fission product yields for a single energy point. This element itself has a number of attributes/sub-elements:

energy

Energy in [eV] at which yields are tabulated

products

Names of fission products

data

Independent yields for each fission product

In the event that a nuclide doesn’t have any known fission product yields, it is possible to have that nuclide borrow yields from another nuclide by indicating the other nuclide in a single parent attribute. For example:

<neutron_fission_yields parent="U235"/>