Reactor emergencies

S. S. Grossel, Design and Sizing of Knockout Drums/Catchtanks for Reactor Emergency Relief Systems, Plant /Operations Progress (July 1986). 

In most cases, a two-phase (vapour/ liquid or gas/ liquid) mixture is vented from a reactor emergency relief system. The relief system required for a two-phase mixture is very often larger (by, in some cases, several times the flow area) than for gas or vapour alone. It is therefore essential to take account of two-phase relief to size a relief system properly. J ... 

S S Grossel, "Design and Sizing of Knock-out Drums/ Catchtanks for Reactor Emergency Relief Systems", Plant/Operations Prog, 5 (3), 129-135,1986... 

A novel type of membrane reactor, emerging presently, is the pervaporation reactor. Conventional pervaporation processes only involve separation and most pervaporation set-ups are used in combination with distillation to break azeotropes or to remove trace impurities from product streams, but using membranes also products can be removed selectively from the reaction zone. Next to the polymer membranes, microporous silica membranes are currently under investigation, because they are more resistant to chemicals like Methyl Tertair Butyl Ether (MTBE) [23-24], Another application is the use of pervaporation with microporous silica membranes to remove water from polycondensation reactions [25], A general representation of such a reaction is ... 

Totally 104 failures have occurred over a total operation period. The abnormal operation events due to equipment and system failures resulted in 28 plant shutdowns of which 18 shutdowns involved reactor scrams (5 events involved manual reactor emergency shutdowns). In the remainder the plant power reductions took place. 

On the upper unit of V-392 reactor 121 nozzles are provided for the members of reactivity control system and reactor emergency protection (CPS) in comparison with 61 nozzles in V-320 reactor. This gives a possibility to vary the number and arrangement of CPS members and to optimise each fuel cycle for reaching the best characteristics of the core safety and efficiency. 

Westinghouse Owner Group. Pressurized Water Reactor Emergency Operating Procedure Manual. USNRC Technical Training Center. 

A Reactor Emergency Plan and Site Emergency Plan (Ref. 6-23, 6-59) have been developed and implemented at SRS. These plans include the following ... 

Provisions for notification and activation of reactor emergency re nse team Technical assessment and mitigation of area emergency conditions Media/public mf( mation... 

Operational intervention levels are not restricted to power-reactor emergencies. They can be calculated for all other types of activities based on the radionuclides present, the exposure pathways and the types of measurement instruments available. 

In practice, for a nuclear reactor emergency, stable iodine should be stocked and distributed at the time of an accident to all staff and emergency workers who are expected to work within the potentially affected area. Stocks should be maintained and replaced after the shelf time recommended by the manufacturer has been exceeded. 

Let us assume for the moment that the difficulties of electrode erosion and of the short-circuiting current can be overcome. In that case a picture of a reactor emerges based on the following features ... 

For the example of the reactor emergency cooling system (Figure 4.8) for which the fault tree had already been set up, the incident sequence... 

Hard-wired interlocks should be provided to prevent opening of the SOj/air isolation valve until the reactor emergency system is primed. The system should be activated by a hard-wired interlock to an organic flow sensor. 

Three rods are intended for reactor emergency shutdown other three rods compensate for reactivity effects and provide power control. 

C. K. Leeper, How safe are reactor emergency cooling systems , Phys. Today 26(8), 30-35... 

The reactor emergency protection system (insertion of the control rods in the core by the effect of gravity). 

Absorber rods in the shutdown systems are standardized in terms of absorber element diameter and number in the shroud tube and also in terms of the dimensions of the shroud tube with rods developed for the BN-800 reactor. The effective density of the absorber material, boron carbide, is also standardized. Five rods are intended for reactor emergency protection, five rods for compensation of the reactivity effects (all rods with B enrichment of 60%) and two rods with natural boron carbide for power control. The reactivity balance during reactor refuelling is given in Table XXI-3. 

The Core-Cooling Task Force report entitled "Report of the Advisory Task Force on Power Reactor Emergency Cooling," which became available in late 1967, concluded that augmented emergency core cooling system was... 

ANSI N320-1979, "Performance Specifications for Reactor Emergency Radiological Monitoring Instrumentation ... 

Provisions for notification and activation of the reactor emergency response team, including the primary and backup means of notification and communication. 

Emergency drills and exercises shall be conducted prior to restart, and at least annually thereafter, to test and verify the adequacy of the reactor emergency plans. The drills and exercises shall (1) Demonstrate the effectiveness of coordination between emergency response team members in the reactor control room, the TSC and the EOF (2)... 

Personnel with reactor safety analysis expertise for augmenting reactor emergency response teams. 

Normal shutdown of the GTR could be accomplished by withdrawing the moveable reflectors and/or inserting the safety rod(s). The GTR will likely also need a rapid shutdown function for reactor emergencies. The fomn of this shutdown function has not yet been determined and requires consideration of such aspects as public safety requirements, single-failure criteria and the desire for the reactor module to be as prototypical as possible to the flight unit. 

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