Eleven officers and sailors from a San Diego-based Navy submarine have been disciplined for falsifying tests on a nuclear reactor and cheating on officer advancement exams.

A Navy report released Friday said crew members of the attack sub Hampton falsified weekly chemical tests as far back as November 2006. The tests involved the highly pure water used to cool the sub's reactor.

Improper chemical levels can lead to erosion.

However, no damage to the reactor core was found when the sub returned to San Diego after a seven-month deployment to the Pacific last year.

The sub's commanding officer and chief engineer were dismissed.