"Underfeeding their machines means they end up with excess uranium ... Enrichers then sell their excess uranium into the spot market". I've often read similar statements and wondered exactly how it works.
If enrichers underfeed, they'll have excess unenriched UF6 leftover. How do they sell this into the spot market, which is U3O8? Do they have to convert it back to U3O8?
It depends on the details of the contract. Sometimes contracts have the enricher responsible for conversion too, so they only send the amount of U3O8 to conversation partners that they choose. Other times the utility manages the conversion contract separately, which does leave the enricher with excess UF6, but that’s not really a problem as UF6 is traded as easily as U3O8 (neither are easy to trade, so to speak, but both have markets!). There can also be realistic relationship between enrichers and utilities, where the enricher is honest about underfeeding and thus only asks the utility to convert a portion of the contracted U3O8 while transferring ownership of the remnant U3O8 to the enricher.
Long story short, you pegged a detail correctly, but no it doesn’t get converted back.
"Underfeeding their machines means they end up with excess uranium ... Enrichers then sell their excess uranium into the spot market". I've often read similar statements and wondered exactly how it works.
If enrichers underfeed, they'll have excess unenriched UF6 leftover. How do they sell this into the spot market, which is U3O8? Do they have to convert it back to U3O8?
It depends on the details of the contract. Sometimes contracts have the enricher responsible for conversion too, so they only send the amount of U3O8 to conversation partners that they choose. Other times the utility manages the conversion contract separately, which does leave the enricher with excess UF6, but that’s not really a problem as UF6 is traded as easily as U3O8 (neither are easy to trade, so to speak, but both have markets!). There can also be realistic relationship between enrichers and utilities, where the enricher is honest about underfeeding and thus only asks the utility to convert a portion of the contracted U3O8 while transferring ownership of the remnant U3O8 to the enricher.
Long story short, you pegged a detail correctly, but no it doesn’t get converted back.