Low pressure coolant injection modification for boiling water reactors

A conventional low pressure coolant injection system for boiling water reactors is provided. With the modification, the cross tie conduits and associated valves remain open between two LPCI divisions. On the occasion of a LOCA, the LPCI pumps (90,91) are activated and injection valves (120,124) for each of the LPCI divisions are opened to commence coolant injection in the recirculation loops (56,57) in simultaneous fashion. However, the rate of flow of water coolant within each injection system is controlled by a hydraulic resistance (118), which is selected to achieve reactor core cooling within requisite time and in requisite quantities from one injection path. Thus, even though coolant water may flow through a rupture within one recirculation loops, sufficient water will be injected in the other loop to achieve core cooling.