Sec Form 3 Filing - Airhart Steven @ Deep Isolation Nuclear, Inc. - 2025-07-23

FORM 3 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Airhart Steven 2. Issuer Name and Ticker or Trading Symbol Deep Isolation Nuclear, Inc. [ NONE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Pres, Freestone Env Svcs (Last) (First) (Middle) C/O DEEP ISOLATION NUCLEAR, INC., 2001 ADDISON STREET, SUITE 300 3. Date of Earliest Transaction (MM/DD/YY) 07/23/2025 (Street) BERKELEY, CA94704 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 381,100 ( 1 ) D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Stock Option (Right to Buy) $ 0.2 ( 3 ) 07/23/2025( 2 ) 02/01/2032 Common Stock 25,837 ( 3 ) D Stock Option (Right to Buy) $ 0.2 ( 5 ) 07/23/2025( 4 ) 04/09/2035 Common Stock 25,837 ( 5 ) D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Airhart Steven C/O DEEP ISOLATION NUCLEAR, INC. 2001 ADDISON STREET, SUITE 300 BERKELEY, CA94704 Pres, Freestone Env Svcs Signatures /s/ Steven Airhart 08/12/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Received in connection with the Issuer's merger (the "Merger") with Deep Isolation, Inc. ("Deep Isolation") in accordance with the terms of the Agreement and Plan of Merger and Reorganization dated as of July 23, 2025, by and among the Issuer (f/k/a Aspen-1 Acquisition Inc.), Deep Isolation Acquisition Corp. and Deep Isolation (the "Merger Agreement"), in exchange for 14,750 shares of Deep Isolation common stock held by the Reporting Person immediately prior to the effective time of the Merger. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, each issued and outstanding share of Deep Isolation capital stock was converted into the right to receive 25.837283 shares of the Issuer's common stock (the "Conversion Ratio"), rounded to the nearest whole share. The Merger closed on July 23, 2025. ( 2 )2. In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 Equity Incentive Plan (the "2018 EIP"), including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares vested as of November 23, 2022 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date. ( 3 )Received in connection with the Merger in accordance with the terms of the Merger Agreement, in exchange for options to acquire 1,000 shares of Deep Isolation common stock at an exercise price of $5.20 per share held by the Reporting Person immediately prior to the effective time of the Merger. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of shares of Deep Isolation common stock subject to each outstanding but unexercised option to purchase Deep Isolation common stock (each such option, an "Outstanding Option," and such number of shares of Deep Isolation common stock subject to such Outstanding Option, the "option shares") was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent. ( 4 )In connection with the Merger and effective as of immediately prior to the effective time of the Merger, Deep Isolation's Board of Directors approved the accelerated vesting of all outstanding and unexercised stock options previously issued under Deep Isolation's 2018 EIP, including the stock options reported herein. Prior to such acceleration, the stock option was subject to a 4-year vesting schedule, whereby 25% of the option shares were scheduled to vest as of April 1, 2026 and 1/48th of the remaining shares were scheduled to vest monthly over the 36-month period thereafter, subject to the Reporting Person's continued service through each vesting date. ( 5 )Received in connection with the Merger in accordance with the terms of the Merger Agreement in exchange for options to acquire 1,000 shares of Deep Isolation common stock at an exercise price of $5.13 per share held by the Reporting Person immediately prior to the effective time of the Merger. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, the number of option shares subject to each Outstanding Option was converted into an option to purchase the number of shares of the Issuer's common stock equal to the option shares multiplied by the Conversion Ratio, rounded to the nearest whole share, and the exercise price of each Outstanding Option was divided by the Conversion Ratio, rounded to the nearest whole cent. The Merger closed on the Merger Closing Date.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.