v3.26.1

MINERAL RIGHTS (Details) - USD ($)		3 Months Ended		6 Months Ended		12 Months Ended
MINERAL RIGHTS (Details) - USD ($)	Jul. 14, 2010	Feb. 28, 2026	Feb. 28, 2025	Dec. 31, 2025	Dec. 31, 2024	Nov. 30, 2025	Jun. 30, 2025	Nov. 30, 2024	Jun. 30, 2024
PROPERTY, PLANT AND EQUIPMENT
Purchase price		$ 18,155	$ 300,000			$ 1,193,415		$ 70,000
Oregon Energy LLC
PROPERTY, PLANT AND EQUIPMENT
Purchase price	$ 2,000,000
Net Smelter Royalty (as a percent)	1.50%
Mineral rights	$ 2,000,000			$ 0			$ 0		$ 0
Maintenance fees on mining claims				75,368	$ 76,227		76,227		$ 95,691
Future annual maintenance payments				$ 72,200			$ 72,200

The amount of expense related to annual maintenance fees on mining claims.

+ References

No definition available.

+ Details

Name:	nucl_MaintenanceFeesOnMiningClaims
Namespace Prefix:	nucl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of future payments related annual maintenance fees.

+ References

No definition available.

+ Details

Name:	nucl_MineralClaimsFutureAnnualMaintenancePayments
Namespace Prefix:	nucl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The percentage of net smelter royalty.

+ References

No definition available.

+ Details

Name:	nucl_NetSmelterRoyaltyPercent
Namespace Prefix:	nucl_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount at the balance sheet date of mineral rights, or rights to extract a mineral from the earth or to receive payment in the form of a royalty for the extraction of minerals, net of amortization.

+ References

No definition available.

+ Details

Name:	us-gaap_MineralRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow from the acquisition of a mineral right which is the right to extract a mineral from the earth or to receive payment, in the form of royalty, for the extraction of minerals.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 13
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

Name:	us-gaap_PaymentsToAcquireMineralRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=nucl_OregonEnergyLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Eagle Nuclear Energy Corp. S-1/A