High-pressure coolant injection

High-pressure coolant injection and reactor core isolation cooling when residual heat removal has failed... 

Core make-up keep core flooding High pressure coolant injection system (2) Low pressure coolant injection system (2) Accumulator tank (2) High pressure coolant injection system (2) Low pressure coolant injection system (2) Rehieling tank (1) Core makeup water tank (2) Automatic depressurization system (2) Accumulator tank (2j Containment vessel water (Water-filled containment vessel) (1)... 

US BWRs have level 8 trips to protect the reactor from getting water in the steamlines, into turbine-powered high-pressure coolant injection (HPCI) turbine, reactor feedwater pump turbines and the main turbine. The SRV s are not designed to relieve liquid as presently configured. 

Increase in reactor coolant inventory - This category of events is eliminated in IRIS since IRIS does not utilize high-pressure coolant injection following a LOG A. The inadvertent actuation of the small emergency boration tanks can be accommodated by the large pressurizer volume with no overpressure or overfill of the RV. 

Inadvertent startup High Pressure Coolant Injection (HPCI or HPCS)... 

Coolant Inventory Control and Core Heat Removal High Pressure Coolant Injection System Reactor Core Isolation Cooling System Low Pressure Coolant Injection System Low Pressure Core Spray System Control Rod Drive Cooling System Condensate System High Pressure Service Water System... 

Low-Pressure Systems High-Pressure coolant injection Core spray... 

The cable spreading room below the control room is significant but not dominant in the fire analysis. The scenario of interest is a fire-induced transient coupled with fire-related failures of the control power for the high-pressure coolant injection system, the reactor core isolation cooling system, the automatic depressurization system, and the control rod drive hydraulic system. The analysis gave credit to the automatic CO2 fire-suppression system in this area. 

These plants are designed with two independent high-pressure injection systems, namely reactor cooling sure coolant injection (HPCl). The associated pumps are each potiered fay turbine. also have a multi-loop core spray system and a multi-mode residual heat re sy.stem that can be aligned for low-pressure coolant injection, shutdown cooling, suppre.ssion pc containment spray functions. 

In order to develop rehable products with a long lifespan, it is necessary to predict possible causes of future damage in the use phase during the early construction phases already. Over the whole product life cycle, mechatronic products (e.g. electronic coolant pumps, high pressure fuel injection pumps, alternators) exhibit highly complex damage causes due to the interactions between the different subcomponents. 

A technical specification for the surveillance of and allowable limit for primary coolant iodine activity implements the corresponding requirements of the NRC STS. The System 8 0+ Standard Design has high head high pressure safety injection, so that additional requirements are not necessary. 

Number of HPSI systems - the number of high-pressure safety injection systems designed to make up for reactor coolant losses in the case of a relatively small leakage, when the pressure drop is small. For reactors without a HPSI system, data providers should enter "N/A". 

Auxiliary feedwater failure not recognized for 8 min Stuck-open relief valve not recognized Loss of coolant not recognized High-pressure safety injection turned off Incorrectly opened drain line valve Steam in primary coolant system not recognized... 

In Siemens BWRs, both, high and low pressure coolant injection systems feed water from the pressure suppression pool into the reactor pressure vessel either via the feedwater line or via separate nozzles directly connected to the feedwater spargers. 

Results from MELCOR (Version 1.8.0) calculations of three accident sequences in a W-PWR 900 Mwe three loop plant are presented. The scenarios considered include an AB sequence and two V type events a rupture of the Low Pressure Coolant Injection System in the auxiliary building, and the rupture of ten steam generator tubes in all cases without the intervention of the active emergency core cooling systems. Emphasis is put on the release and transport of core materials. It has been found that deposition of vapors from the most volatile species is high within the core structures. Later in the accident, revaporization induced by decay heat takes place, at times in coincidence with the production of steam due to core slumping, what may change the nature and composition of source terms. 

Several other systems are available to control room operators to keep the reactor cool during an emergency. These include the High Pressure Core Spray System, Low Pressure Core Spray System, Residual Heat Removal System, Low Pressure Coolant Injection, and Suppression Pool Cooling. All of these systems require both AC and DC power, plus a sufficient flow of coolant water connected to the ultimate heat sink. At Fukushima this ultimate heat sink was the Pacific Ocean (US Nuclear Regulatory Commission, n.d.a). 

The core make-up water tanks are used in the design of AC600/1000 so as to eliminate the high-pressure safety injection pumps and increase reliability of the safety system. The function characteristics and coolant flow transient of core make-up water tank, accumulator and automatic depressurization system can be tested using NPIC core make-up water tank experiment facility to simulate a small LOCA. The facility parameters are as the following ... 

Passive core make-up water tank is used so as to eliminate high pressure safety injection pumps. Transient characteristic research of core make-up water tank in the case of small LOCA were performed. The break sizes are 2, 6, 12, 18, 30 mm respectively. Thermal hydraulic behaviors of pressurizer and draining flow rate measurement from core make-up water tank to primary coolant system following small LOCA were researched and carried out in the test. A total of 80 sensors were used to measure temperatures, liquid level and flow rate. 

In some BWR transient scenarios, the high pressure injection systems are postulated to fail. To make use of the low pressure injection system, it is necessary to depressurize the reactor coolant system, a function performed by the automatic depressurization system (ADS). In the scenario considered, ADS actuation is manual because the signals for automatic initiation of the system are not present. 

A similar technique is applied to low-density polyethylene reactors. Some of these systems operate in cooled tubular reactors at a very high pressure. Since the reactor has a thick tube wall, the temperature response to changes in the coolant is slow. Instead, the reaction rate (and thereby temperature.) is controlled by injecting initiator at select places along the length of the reactor tube (see Fig. 4.28). 

Fluidization allows better removal of the heat generated by the reaction, by means of coils sunk in the catalyst mass, conveying a coolant fluid and producing high-pressure steam. However, it requires auxiliary units, including cydone separators to recover entrained solid particles, reactant injection and distillation systems, etc. 

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