(b) any equipment or device designed or used for (1) separating the isotopes of uranium or plutonium, (2) processing or utilizing spent fuel, or (3) handling, processing or packing waste.

(c) any equipment or device used for the processing, fabricating or alloying of special nuclear material if at any time the total amount of such material in the custody of the Insured at the premises where such equipment or device is located consists of or contains more than 25 grams of plutonium or uranium 233 or any combination thereof, or more than 250 grams of uranium 235.

(d) any structure, basin, excavation, premises or place prepared or used where any of the foregoing is located, all operations conducted on such site and all premises used for operations; Nuclear reactor means any apparatus designed or used to sustain nuclear fission in a self-supporting chain reaction or to contain a critical mass of fissionable material; with respect to injury to or destruction of property, the word injury or destruction includes all forms of radioactive contamination of property.

### III. DEFINITIONS

1. **Damages** are all sums that the Insured is legally obligated to pay because of bodily injury, personal injury, property damage or advertising injury covered by this policy. This obligation of the Insured to pay arises out of a final decision of a court or is the result of a settlement which we have approved in writing. Damages include interest which accumulates on a civil court judgment from the time the suit is brought until the final judgement is entered by the courts. Damages include defense expense to the same extent included in the controlling underlying insurance policy(ies). Damages do not include fines or penalties. Damages do not include damages for which insurance is prohibited by law or public policy in construction of this policy.

2. **Underlying Insurance** means the underlying insurance policies contributing to the total limit stated in item 4 of the declarations and includes any renewals or replacements thereof.

3. **Controlling underlying insurance policy(ies)** means the insurance policy(ies) designated as such in Item 5 of the declarations.

4. **Insured** means the Insured named in the Declarations, any Insured under the controlling underlying insurance policy(ies) and any additional Insured added to the policy by endorsement attached hereto.

### IV. CONDITIONS

1. **MAINTENANCE OF UNDERLYING INSURANCE**

This policy is subject to the same terms, definitions, exclusions and conditions (except as otherwise provided herein) as are contained in or as may be added to the controlling underlying insurance policy(ies) stated in Item 5 of the Declarations.

You agree to maintain all insurance policies affording in total the coverage and limits as stated in Item 4 of the declaration in full force and effect during this policy period, except for reduction of aggregate limits where applicable, solely as a result of the payment of claims for occurrences which take place on or after the effective date of this policy.

You agree to notify us within sixty days if any company replaces or changes any terms or conditions of any of the underlying insurance. Your failure to comply with the foregoing shall not invalidate this policy, but in the event of such failure, we shall be liable only to the extent that we would have been liable had you complied herewith.

2. **NOTICE OF OCCURRENCE, CLAIM OR SUIT**

Whenever it appears that an occurrence, claim or suit is likely to involve payment under this policy, written notice shall be given to us or our authorized representative by you or your designated representative as soon as practicable. Such notice shall contain particulars sufficient to identify the Insured and also reasonably obtainable information respecting the time, place and circumstance of the occurrence, claim or suit, the names and addresses of the injured and of available witnesses.

3. **OTHER INSURANCE**

The insurance afforded by this policy shall be excess insurance over all underlying insurance covering a loss covered by this policy whether or not valid and collectible. It shall also be excess insurance over all other valid and collectible insurance (except other insurance purchased specifically to apply in excess of this insurance) which is available to the Insured, covering a loss also covered by this policy.

4. **ACTION AGAINST COMPANY**

No action shall lie against us unless, as a condition precedent thereto, there shall have been full compliance with all of the terms of this policy, nor until the amount of the Insured's obligation to pay shall have been finally determined either by judgement against the Insured, after actual trial, or by written agreement by the Insured, the claimant and us.

5. **SUBROGATION**

In the event of any payment under this policy, we shall participate with the Insured and any underlying insurer in the exercise of all the Insured's rights of recovery against any person or organization liable therefore, and the Insured shall execute and deliver instruments and papers and do whatever else is necessary to secure such rights. The Insured shall do nothing to prejudice such rights.