ANSI/ANS-55.6-2026

Liquid Radioactive Waste Processing System for Light Water Reactor Plants

This standard sets forth minimum design, construction, and performance requirements, with due consideration for operation, of the liquid radioactive waste processing system (LRWPS) for light water reactor (LWR) plants for design-basis inputs. It is applicable to routine operation, including design-basis fuel leakage and other design-basis occurrences.  For the purposes of this standard, the LRWPS begins at the interfaces with the reactor coolant system pressure boundary, at the points of discharge for lines from other systems, or at the discharge from the building sumps that are provided for the collection of liquid waste that has the potential of containing radioactive material. The system excludes drywell sumps and safety-related systems. The system terminates at the point of interface with the waste solidification system, at the point of recycle back to storage for reuse, and at the point of controlled discharge to the environment.  The LRWPS components are not nuclear safety related (SR or Q). The system is important to safety and may be classified as augmented or graded QA (S) or non-safety (NS). See Sec. 3.3 of ANS-51.1-1983 (withdrawn) and Sec. 3.3 of ANS-52.1-1983 (withdrawn) for definitions of “safety class” and “non-nuclear safety.”