Release surveys
Before any container leaves the decay-storage room — to ordinary trash, to a broker, or to the sanitary sewer — it must be surveyed with alpha-capable instruments and documented per RSO procedure. Release-survey discipline is the single most inspector-visible part of the waste program.
Procedure elements
Direct frisking
ZnS scintillation probe at fixed probe-to-surface distance (typically ≤1 cm), scan rate per written procedure. Result must clear background by the threshold defined in your written procedure on both alpha and gamma channels.
Wipe test
Wipe representative interior and exterior surfaces, count on the low-background alpha (or alpha/beta) counter. Wipe tests catch fixed contamination that direct frisking can miss. Both tests must pass before release.
Documentation
Date, isotope, container ID, surveyor, instrument and serial number, calibration date, background reading, container reading, result, and disposition. Counter-signed where your procedure requires.
Failure pathway
Containers that fail release survey return to decay storage with a new expected release date and a note in the inventory log. Never re-survey-and-release without documenting the original failure — that is the audit-trail break inspectors look for.
Common release-survey mistakes
What goes wrong
Gamma-only survey on alpha-bearing waste. Background reading not recorded with each survey. Same surveyor signing as both performer and verifier. Re-release after a failure with no documented re-test.
What good looks like
Alpha + gamma channels, both documented. Background re-measured at the start of each session. Performer and verifier are different people. Every failure has a release-or-rework record attached.
Pre-printing the release-survey form with the required fields helps. Hand-written free-form notes are a common reason survey records fail audit — not because the survey was bad, but because the documentation is illegible or missing a field.
- 10 CFR §35.92 — Decay-in-storage.
- 10 CFR §20.1501 — General radiation survey requirements.