In a nuclear installation, an instrument includes a sensor module connected to a process flange. The sensor module includes a support conduit with support conduit threads. An electronic circuit is wired to a connector that includes a key that is aligned with field circuit contacts of the connector. A thermal and nuclear radiation shield encloses the electronic circuit and includes a shock protection annulus. The connector is secured inside the shock protection annulus. The thermal and nuclear radiation shield includes shield threads that rotatably engage the support conduit threads to rotate an alignment of the key relative to the process flange.