Beneficiary Organisation Details

Slovenske Electrarne (Slovakia)
http://www.seas.sk/

CEZ (Czech Republik)
http://www.cez.cz/eng/

Project Aims

• Assessment of sump intake currently installed at Bohunice and Dukovany NPP versus safety requirements related to clogging. Currently installed NEROFIL thermal insulation and future JERZIL HF insulation (planned for Dukovany NPP) have been considered;
• Assessment of sump clogging testing methods;
• Proposal for a new sump intake design coping with safety requirements related to clogging.

Project Results

First objective:

• Sump intake currently installed at Bohunice NPP does not allow to fulfil safety requirements related to sump screen clogging: a new design is clearly needed;
• Insulation planned to be installed at Dukovany NPP (JERZIL HF) does not improve (and even makes worse) safety status of the plant versus sump screen clogging issue.

Second objective:

• Thermal ageing of insulation can widely modify results of clogging tests. In case of NEROFIL, aged insulation leads to faster clogging;
• Debris generation (i.e. insulation destruction) can be performed with a cold water jet, as it is easier for use. Comparison of realistic hot water/steam jet with more simple cold water jet does not lead to significant changes of sump screen clogging results.

Third objective:

• A new sump intake detailed design has been proposed. This new design, structurally simple and conservative, allows to meet safety requirements related to sump screen clogging issue. “Box strainer” design has been selected, and special design provisions have been proposed (additional filtering planes outside sump pit) for centre sump, which is rather small in comparison with side sumps.

Further Project Results

a) See the attached file;
b) Further information on the project results could be sought from the beneficiary organisation.