# Spent Fuel Pool Drum

Each drum slot holds one item, which is replaced by the first entry of the first output position; `count` is ignored.

## Fields

| Field | Meaning and default | Range |
| - | - | - |
| `type` | Selects the `hbm:fuel_pool` recipe format. | |
| `name` (Optional) | Internal lookup name; defaults to the last segment of the recipe resource path. | |
| `input_items` | Ordered counted item inputs; defaults to an empty list. | |
| `input_items.ingredient` | Item ID, item tag, or loader ingredient object. | |
| `input_items.count` (Optional) | Items required from one stack; default 1. The item stack limit bounds a usable count. | `[1, i32::MAX]` |
| `input_items.components` (Optional) | Exact item-component values. | |
| `input_items.predicates` (Optional) | Item-component predicates. | |
| `output_items` | Fixed or weighted item-output positions; defaults to an empty list. | |
| `output_items.item ID` | Fixed output: String form for one item. | |
| `output_items.id` | Item ID in a stack object. | |
| `output_items.count` (Optional) | Stack size; default 1. | `[1, 99]` |
| `output_items.components` (Optional) | Item-component values. | |
| `output_items.chance` (Optional) | Output chance; omit for a guaranteed output. Some machines roll each item of the stack separately. | Rounds to weight `[1, 999]` of 1000 |
| `output_items.data` | Weighted choice: Stack object or an empty object for no output. | |
| `output_items.weight` | Relative selection weight; a positive total selects an output. | `[0, i32::MAX]` each; $\sum_i w_i \le \texttt{i32::MAX}$ |
| `order` (Optional) | Sort position within the recipe table; lower values first, default 2147483647. | `i32` |

## Example

Source path: `data/hbm/recipe/fuel_pool/fuel_pool.pwr_fuel_hot_mea.json`

```json
{
  "type": "hbm:fuel_pool",
  "input_items": [
    {
      "ingredient": "hbm:pwr_fuel_hot_mea"
    }
  ],
  "order": 25,
  "output_items": [
    "hbm:pwr_fuel_depleted_mea"
  ]
}
```