Nuclear power plants – Instrumentation important to safety – Temperature sensors (in-core and primary coolant circuit) – Characteristics and test methods
|Publication Date:||1 June 2010|
|ICS Code (Nuclear power plants. Safety):||27.120.20|
This International Standard is applicable to general aspects of system and component design, manufacturing and test methods for temperature sensors used in-core and for the primary coolant circuit in nuclear power reactors.
These sensors include thermocouples and RTDs (Resistance Temperature Detector-RTD). Emphasis is placed on the features specific to the nuclear application and recommendations concerning components and sensors are made only when they relate to the containment of such components within the reactor primary envelope and/or in high radiation fields.
The conditions imposed by reactor use are often different from those which occur in nonnuclear applications. Parts of the in-core system may be located in very severe environments.
Exposure to high neutron and gamma radiations is liable to cause error due to nuclear transformations, heating and structural changes, and to affect the mechanical and electrical properties of the equipment so that extra care has to be taken in the standards adopted for installations and in the choice of materials.
Furthermore, design consideration needs to be given to the effects of high environmental pressure, high temperature, temperature gradients and temperature cycling as well as to the way in which the temperature measuring system could influence the safety or economic performance of the reactor.
The consequences of nuclear conditions for temperature sensors lead to strong requirements regarding qualification.
This standard deals with specific requirements for nuclear applications of temperature sensors. It has two purposes:
a) to provide a guide which will help to ensure that the reactor conditions do not damage the temperature sensors;
b) to ensure that the in-core temperature measuring system and the sensor installation do not prejudice the safe operation and the availability of the reactor.
Statements of general applicability are made but detailed consideration is restricted to thermocouples and RTDs.