Document: NUREG-0800
Document ID: 09e53ce5-bec3-4415-82d1-82ee125cb7c1
Document Type: srp
Title: describes the design acceptance criteria for the LWMS.  The classification of
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070720635.pdf
Revision Date: 2023-06
Chapter: 11
Section ID: 11.2
CFR Part: 
CFR Title: 

Content:
LWMS equipment and piping and bases governing design criteria should be developed in accordance with the guidelines of Regulatory Guide 1.143, as described in SRP acceptance BTP 11-6-2 March 2007 criteria. In addition, the design should incorporate features to reduce leakage and spills, and facilitate operation and maintenance in accordance with the guidance of Regulatory Guide 1.143 and requirements of 10 CFR Part 20.1406. LWMS design features and characteristics differ among plants, but the most important common characteristic among plants is that designs incorporate the guidance of Regulatory Guide 1.143. As a result, a gross failure of the LWMS is considered highly unlikely, e.g., such as a failure involving the near total loss of the system’s inventory of radioactive materials. However, the malfunction of a tank and its components, a valve misalignment, tank overflow, or an operator error appear more likely and are assumed to be types of failures warranting an evaluation of their consequences. Although no specific types of system failures have been designated as being representative, it was considered that for the safety evaluation of the LWMS, the type of malfunction analyzed should be limited to the postulated failure of a tank or pipe rupture, located outside of containment. The evaluation considers the impact of the failure on the nearest potable water supply, and the use of water for direct human consumption or indirectly through animals (livestock watering), crops (agricultural irrigation), and food processing (water as an ingredient). The purpose of this BTP is to provide guidelines in defining the mechanism of the failure, assumptions used for the analysis, and approach applied in assessing the radiological impact. The objective is to develop an estimate of the amounts of radioactive materials released in an unrestricted area, and provide reasonable assurance that the radiological consequences of the failure of an active component in the LWMS will not