Nuclear Plant - Active Component (Valves)

[MastersBound]

This is for all you System guys. What are the classifications for a valve to be considered an Active Component? Also, if the valve is classified as an Active Component does it automatically mean that the valve is a Safety Related Valve? I have several valves in my system (Check, Control, Isolation) that are Safety Related Valves but are not considered Active Components... Why?

Any NRC, IAEA, or the likes reference material is helpful.

Thanks

 

[NUCENG]

This is for all you System guys. What are the classifications for a valve to be considered an Active Component? Also, if the valve is classified as an Active Component does it automatically mean that the valve is a Safety Related Valve? I have several valves in my system (Check, Control, Isolation) that are Safety Related Valves but are not considered Active Components... Why?

Any NRC, IAEA, or the likes reference material is helpful.

Thanks

A valve is an active component because it changes state. It is safety related and active if it has to reposition to accomplish its safety function. (For example an isolation valve must close to perform its safety function, an RHR vslve has to open to create the flowpath for its safety function, and an SRV must both open and close to perform its safety functions.) Not every valve is safety related, but every valve is an active component. An isolation valve that is installed for maintenance in a safety system may not be required to reposition for a safety function if it is normally open. In this case the valve has a safety function of pressure boundary, but no active safety functoion.

I will see if I can find a discussion reference and edit this post. In the meantime you may want to search for :active component: or :active safety function: on the NRC website

edit:
10 CFR 50 Appendix A Criterion 43 specifies valves as "active" components. The safety function for a valve requires that the system have a safety function. Any activation, isolation or repositioning of the valve during a mode change of the system will result in the valve having an active safety function. If the valve doesn't reposition it still has a passive safety function if the system is safety related.

 

[raining Pete]

for the question! The classifications for a valve to be considered an Active Component can vary depending on the specific system and standards being used. Generally, an Active Component is defined as a component that is necessary for the normal operation of a system, and is capable of being controlled, monitored, or manipulated. This includes valves that are used for control, regulation, or isolation purposes.

However, just because a valve is classified as an Active Component does not necessarily mean that it is also a Safety Related Valve. Safety Related Valves are those that are specifically designated for the safety of the system or plant. These valves are typically required to meet stricter design and testing standards and may have redundant or fail-safe features.

It is possible for a valve to be classified as an Active Component but not be considered a Safety Related Valve. This could be due to a variety of factors such as the level of risk associated with the valve, its location within the system, or the specific design and function of the valve.

As for sources for more information on these classifications, the Nuclear Regulatory Commission (NRC) and the International Atomic Energy Agency (IAEA) both have guidelines and standards for the design and operation of nuclear power plants. These can be helpful resources for understanding the classifications and requirements for valves in these systems.

I hope this helps clarify the classifications for Active Components and Safety Related Valves in your system. If you have any further questions, don't hesitate to ask or consult with the appropriate regulatory agency for more specific information.