Seal arrangement for in-core instrument housing

In combination, a nuclear reactor in-core instrument housing, an in-core instrument inserted within said instrument housing, and a seal arrangement for providing a seal between said instrument and said instrument housing, the seal arrangement comprising:

• a first seal assembly surrounding an outer portion of said in-core instrument housing;
• a second seal assembly surrounding an outer portion of said in-core instrument;
• a seal housing having first and second ends, said seal housing enclosing said first and second seal assemblies;
• and
• first and second compression assemblies positioned on said first and second ends of said seal housing, respectively, said first compression assembly engaging said first seal assembly to maintain a seal between said first end of said seal housing and said outer portion of said in-core instrument housing, and said second compression assembly engaging said second seal assembly to maintain a seal between said second end of said seal housing and said outer portion of said in-core instrument.

A method of sealing a nuclear reactor in-core instrument housing, comprising the steps of:

• positioning a first compression assembly and first seal assembly around an outer portion of the in-core instrument housing;
• positioning a seal housing over an end of said in-core instrument housing;
• positioning a second seal assembly and second compression assembly around an outer portion of an in-core instrument contained within the in-core instrument housing;
• and
• threading respective drive nuts of said first and second compression assemblies onto said seal housing to maintain a compressive sealing force against said first and second seal assemblies.