4.158. A hydrogen monitoring or sampling system should be provided within the containment for determining the hydrogen concentrations at represent­ative points over time in accident conditions, especially those caused by a LOCA. If mixing of the containment atmosphere cannot be guaranteed, proper location is essential for the monitoring or sampling devices to be representative of the areas and locations where hydrogen might accumulate.

4.159. If the systems for hydrogen monitoring or sampling could transport radionuclides outside the containment, they should be considered extensions of the containment and should be designed to meet the same criteria as the containment itself.

4.160. Systems for hydrogen removal, deliberate ignition, homogenization or inerting should be provided so as to avoid reaching the hydrogen ignition limit globally or locally inside the containment at any time during or after a postulated LOCA.

4.161. If hydrogen control systems could transport radionuclides outside the containment, they should be considered extensions of the containment and should be designed to meet the same criteria as the containment itself.