Firefighters were called out to HMP La Moye on Saturday night to tackle a blaze in the prison kitchen.
Prison staff called 999 shortly after 8pm, and all the emergency services were dispatched as a precaution.
The fire was put out a short time later.
No one was injured during the incident, and the Prison Service says there is 'no suggestion' of any suspicious activity or the fire being started deliberately.
Contingency plans have been brought in to make sure prisoners are being fed as normal.


First Jersey oyster shipment arrives through Granville facility
Storm Austen: Clean-up continues
Storm Austen: All you need to know
Haut Du Mont: Jury fails to reach verdict on third gas worker
Storm Austen: Government schools to close on Friday
Haut du Mont: Gas workers convicted of manslaughter
Campaign encourages potential child sex offenders to seek help
Electric car charger grant to end in December