The RSK was informed, among others by the BMU, about the status of the EU stress tests and on the progress of work of the RSK ad hoc working groups (see 445th RSK meeting).

The RSK discussed and adopted the following statements:

"Loss of the ultimate heat sink",
"Stress analysis and testability of the weld at the joint between the cylinder and lower bottom head in reactor pressure vessels (RPVs) of nuclear power plants with boiling water reactors of the BWR-69 type Krümmel (KKK), Brunsbüttel (KKB), Philippsburg, Unit 1 (KKP-1) and Isar, Unit 1 (KKI-1)", and
"Recommendations on the maximum permissible critical boron concentration to ensure subcriticality after operation in 'reflux condenser mode' during a small-break loss-of-coolant accident".

The RSK laid down its consultation programme under consideration of the findings from the events in the Japanese plant in Fukushima. Furthermore, the agenda for the closed meeting in September was discussed.

The RSK adopted the recommendation "Regulations on plant conditions after occurrence of an incident" (in German).

The RSK adopted its statement on the proof of the technical qualification of nuclear power plant personnel. The report of the RSK Committee on ELECTRIC INSTALLATIONS (EE) "Testing and monitoring programme for oil-paper insulated transformers and dry transformers in German nuclear power plants" was discussed. The consultations on the topic of robustness have been continued and on the RSK’s understanding of the safety philosophy started.

At its 442nd meeting, the RSK was informed by the Federal Network Agency regarding the supply security of German nuclear power plants in view of possible stability problems in the German power grid. Further consultations are to take place in the ad-hoc working group NETZ (grid) of the RSK Committee on ELECTRIC INSTALLATIONS (EL). The RSK adopted its short definition of the term "robustness" under the boundary conditions of the EU stress tests, in which the terms cliff edge effect and robustness are explained according to the definitions of the IAEA and ENSREG. A more detailed description will follow.

The RSK was informed, among others by the BMU, about the status of the EU stress tests.
The RSK discussed and adopted the following statements:

Plant-specific safety review (RSK-SÜ) of German research reactors in the light of the events in Fukushima-1 (Japan) (“Anlagenspezifische Sicherheitsüberprüfung (RSK-SÜ) deer Forschungsreaktoren unter Berücksichtigung der Ereignisse in Fukushima I (Japan)”) (in German),
Leakages from steam generator (SG) tubes to be postulated: multiple tube rupture/leak opening of wall thickness-reduced SG tubes (“Zu unterstellende Leckagen an Dampferzeuger(DE)-Heizrohren: Mehrfachrohrbruch/Lecköffnung wanddickengeschwächter DE-Heizrohre”) (in German), and
Application of the operating manual during operation of German nuclear power plants (“Anwendung des Betriebshandbuches im Fahrbetrieb deer Kernkraftwerke”) (in German).

The RSK-structured its consultations in connection with the RSK safety review, taking into account the EU stress test process, and defined the terms outage operation and post-operational phase for this work. Furthermore, the current situation regarding the storage of irradiated fuel elements in the decommissioned German plants was presented and discussed. The consultations on the detailed definition of the RSK’s understanding of robustness have started.

The 440th meeting was held on 15.09. as a closed meeting and on 16.09 as a regular meeting. At the closed meeting, the RSK adopted a representation of its understanding of its tasks and its way of working. The consultations on a "memorandum of the RSK to ensure the best possible safety of nuclear installations" have begun.

At the meeting on 16.09., the RSK structured the work on the final assessment of the “Plant-specific safety review (RSK-SÜ) of German nuclear power plants in the light of the events in Fukushima-1 (Japan)” and established several ad hoc working groups for it. The RSK has been informed about the report "Computer-based safety I&C for use in the highest safety category in German nuclear power plants - presentation of the consultation results of the RSK working group USE OF COMPUTER-BASED I&C (ERL)" (in German).

At the meeting, GRS reported on the evaluation of periodic safety reviews of German nuclear power plants. The RSK intends to request reports on the implementation of measures resulting from the reviews.

At the meeting, the RSK took note of the report of the RSK Committee on PLANT AND SYSTEMS ENGINEERING (AST) on the “Superposition of events with system operating conditions of short duration” (in German) and continued the consultations on the statement “Operating documents: requirements and conditions of safe operation” and on the “RSK’s understanding of the safety philosophy”.

The RSK discussed assessment criteria for the evaluation of the operator reports within the framework of the "Plant-specific safety review of German nuclear power plants in the light of the events in Fukushima-I ".

The discussions have to be continued at the next meeting.

The discussions on the assessment criteria for the evaluation of the operator reports, started at the 435th meeting, were completed.