6.1: Reliability Of ESBWR Safety Systems
6.1 ESBWR safety conclusions
a) Reliability of ESBWR safety systems
The passive safety systems used in ESBWR are innovative and since they never been used before, there was a need to verify them. Several tests have been conducted to proof their reliability[7]. The most important were the GDCS Integral System Test(GIST) the qualification test of GDCS in a full-height, scaled volume test facility[1] and the PCCS and containment performance test, done in a low pressure, full height model in PANDA facility[7]. Both tests proven the concepts of these passive safety systems.
b) Core damage frequency
Thanks to the safety systems used in ESBWR the core damage frequency 1.7 x 10-8 per reactor year was achieved[1]. It is much lower than the US Nuclear Regulatory Commission requirement, which is 10-4 per reactor year[11]. It is also lower than in the previous GE reactor, the ABWR, where the frequency is 1.6 x 10-6[5]. The main …show more content…
The probable reason for this is the higher redundancy used in ESBWR.
b) Containment cooling system
As it was said before, both projects incorporate Passive Containment Cooling Systems, but designed with a completely different approach. The compact wet ESBWR containment seems to be a better concept, because of some concerns about the AP1000 containment. In the Westinghouse design there is no secondary containment, which should be present according to the defense in depth principle. This issue was addressed in a report written by Arnold Gundersen[12], where he noticed that the steel containment can be vulnerable to corrosion and the concrete shield is open to the atmosphere. In case of a leakage from the steel containment, radioactive gases and liquids will be vented to the environment and the stack effect will even enhance the
a) Reliability of ESBWR safety systems
The passive safety systems used in ESBWR are innovative and since they never been used before, there was a need to verify them. Several tests have been conducted to proof their reliability[7]. The most important were the GDCS Integral System Test(GIST) the qualification test of GDCS in a full-height, scaled volume test facility[1] and the PCCS and containment performance test, done in a low pressure, full height model in PANDA facility[7]. Both tests proven the concepts of these passive safety systems.
b) Core damage frequency
Thanks to the safety systems used in ESBWR the core damage frequency 1.7 x 10-8 per reactor year was achieved[1]. It is much lower than the US Nuclear Regulatory Commission requirement, which is 10-4 per reactor year[11]. It is also lower than in the previous GE reactor, the ABWR, where the frequency is 1.6 x 10-6[5]. The main …show more content…
The probable reason for this is the higher redundancy used in ESBWR.
b) Containment cooling system
As it was said before, both projects incorporate Passive Containment Cooling Systems, but designed with a completely different approach. The compact wet ESBWR containment seems to be a better concept, because of some concerns about the AP1000 containment. In the Westinghouse design there is no secondary containment, which should be present according to the defense in depth principle. This issue was addressed in a report written by Arnold Gundersen[12], where he noticed that the steel containment can be vulnerable to corrosion and the concrete shield is open to the atmosphere. In case of a leakage from the steel containment, radioactive gases and liquids will be vented to the environment and the stack effect will even enhance the