RELATED PARTY - Schedule of transactions - General Atomics (Details) - General Atomics - USD ($) $ in Thousands		3 Months Ended
	Apr. 01, 2024	Mar. 31, 2024	Mar. 17, 2022
Related Party
Balance of funds remaining on deposit with General Atomics as a prepaid expense at beginning of period	$ 2,629	$ 3,435
Funds transferred to General Atomics during the period		2,000
Company's share of Demonstration Plant project costs incurred during the period		(2,806)
Balance of funds remaining on deposit with General Atomics as a prepaid expense at end of period		2,629
Commitment amount		$ 17,700	$ 5,318
Subsequent Event
Related Party
Funds transferred to General Atomics during the period	4,000
Commitment amount	$ 21,700