At this meeting, the prevailing topic of discussions was the further proceeding regarding the project on update of the nuclear rules and regulations of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) after its follow-up (module Version B) on the basis of the workshop series. The RSK agreed on a proceeding with five working groups which primarily review different module topics by means of an assessment catalogue. Their results shall be compiled for the RSK. On the basis of the preparatory work of a working group, scope and contents of this assessment were discussed.

At this meeting, the prevailing topic of discussions was the further proceeding regarding the project on update of the nuclear rules and regulations of the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) after its follow-up (module Version B) on the basis of the workshop series. The RSK agreed on a proceeding with five working groups which primarily review different module topics by means of an assessment catalogue. Their results shall be compiled for the RSK. On the basis of the preparatory work of a working group, scope and contents of this assessment were discussed.

The statement on defective medium-voltage cables with safety significance at German nuclear power plants (in German) prepared by the RSK Committee on ELECTRIC INSTALLATIONS (EE) and the statement on radiation damage in rock salt (in German) prepared by the RSK Committee on FUEL SUPPLY AND WASTE MANAGEMENT (VE) were adopted.

At its 366th meeting, the discussions of the RSK concentrated on the following topics:

Damages at the control assemblies in boiling water reactors,
seismic safety for longer-term interim storage of low and intermediate level wastes,
alerting of the civil protection authority by the operators of nuclear installations,
draft standards of the Nuclear Safety Standards Commission (KTA), and
further development of the nuclear rules and regulations.

Due to damages at control assemblies identified a two Japanese and one American nuclear power plant, the RSK discussed above all, with regard to the applicability of these events to German plants, the damage mechanisms, their significance for the shut-down safety of the reactor and measures for their prevention. The RSK arrived at the conclusion that under consideration of specified boundary conditions no damages are to be expected which might impair the shut-down safety of the reactor. The details are included in a RSK statement (in German).

Following several discussions, the RSK discussed the need for modification regarding the review of the seismic design of storage facilities for the longer-term interim storage of low and intermediate level wastes. It adopted a modification of Section 2.7.1 of its "Safety requirements on the interim storage of low and intermediate level waste in the longer term".

The Commission on Radiological Protection (SSK) and the RSK revised the version of the above-mentioned alerting criteria of 1994. With regard to system design, the update consists of a revision as well as an extension to the low-power and shut-down operation and to the fuel pool. The updated joint recommendation of the SSK and the RSK is available here (in German).

The annual meeting of the Nuclear Safety Standards Commission (KTA) on 11.11.2003 dealt, among others, with the update or amendment of technical standards of the KTA. For this purpose, the RSK, as member of one of the fractions in the KTA, decided on a vote for each of these standard revision projects.

Within the framework of a BMU project on the general revision of the nuclear rules and regulations, the RSK intends to update the RSK guidelines for pressurised water reactors of 1996. First of all, it discussed structurings and procedures.

The discussion of the RSK extended to the following subject maters:

Corrosion at the reactor pressure vessel of the Davis Besse nuclear power plant (USA),
non-availability of valves at the Unterweser nuclear power plant (KKU), and
criticality safety for the final disposal of plutonium.

March 2002, a corrosion cavity (width of 100 to 125 mm) and a gap (length of about 180 mm) - caused by boric acid leaks - was detected on control rod drive mechanism nozzles of the RPV head. The major part of the steel of the reactor pressure vessel with a wall thickness of about 168 mm was corroded down to the cladding. The medium thickness of the remaining cladding in this area was about 6.5 mm. Laboratory analyses showed a crack at the surface of the cladding with a length of about 9.5 mm which was not through-wall. This event to be regarded as severe one, gave reason to examine its applicability to nuclear power plants in Germany. In the opinion of the RSK, the event is mainly due to deficiencies in the maintenance management of this US-American plant operator. At German plants, there is a more stringent maintenance management and monitoring system. The RSK will discuss in depth questions related to the materials, corrosion processes and plant management before it concludes its statement.

Regarding the reportable event at the Unterweser nuclear power plant (KKU) of 6.6.1998 (unavailability of one of four main steam safety and relief valves when demanded), the RSK adopted a statement (in German) prepared by the RSK Committee on REACTOR OPERATION (RB). It arrives at the conclusion that the plant operator established an appropriate programme in the organisational/administrative area in order to counteract a recurrence of such events. The programme includes a modern, process-oriented management system which the RSK regards as relevant also for other plants.

On the criticality safety for the final disposal of plutonium, the Committee on SUPPLY AND WASTE HANDLING (VE) had submitted a status report to the RSK. The report includes the procedures and boundary conditions that would have to be considered when emplacing plutonium-containing radioactive wastes and irradiated fuel elements in a repository in order to avoid also over geological periods of time that a condition may occur which leads to criticality. In view of the geometric, geological and geochemical conditions changing over very long periods of time, some of the scenarios to be considered could only be based on processes in an idealised form and a conservative approach. The status report, shall contribute to the continuation of the scientific discussion and the promotion of the further development of the methods so that the scenarios and boundary conditions for the future selection of a repository site can be derived specifically for the host rock selected.

DThe RSK discussed and assessed the improper handling during the transport of a fuel element at the Neckarwestheim I nuclear power plant (GKN-I) and a primary neutron source at GKN II (in German). The events occurred in June 2002. The RSK based its discussion on the examination of its Committee on REACTOR OPERATION (RB) which started to discuss the causes of the events in January 2003 and assessed the corrective measures of the plant operator. The RSK is of the opinion that the technical and organisational measures of the plant operator initiated in this connection are target-oriented, systematic and well structured. It still sees possibilities to improve the experience feedback system, training measures and ergonomics.

Against the background of the revision of the nuclear rules and regulations within the framework of a project of the Federal Ministry for the Environment, the RSK continued its discussions on the update of the RSK guidelines for pressurised water reactors of 1996 (summary report of the 366th RSK meeting). The update shall include the boiling water reactors and - more detailed than before - requirements on man- technology-organisation and present the requirements on the verification methods. A first structuring of the new guidelines has been established, the committees of the RSK are now dealing with the further specification.

This meeting concentrated on the ageing management at nuclear power plants and probabilistic methods and procedures regarding safety-related questions. The RSK discussed instructions prepared by its committees, how, in particular, it can be avoided for mechanical components, electrical components, I&C components, structural components, integrated operation management systems, and for the personnel competence that the safety level is reduced due to ageing processes by respective measures. The RSK intends to compile the result of these discussions in a recommendation that will also include the RSK statement of 10.01.2002.

Within the framework of the planned update of the RSK guidelines (summary report of the 368th RSK meeting), the RSK discusses the significance of probabilistics in supervision procedures by means of practical applications and the need for implementation in the new rules and regulations.

The RSK will continue the discussion on both topic areas.

At this meeting, the RSK concluded its previous discussions on the applicability of corrosion indications at the American 'Davis Besse' nuclear power plant to nuclear power plants in Germany. Although the circumstances and conditions as existing at Davis Besse are not directly applicable to German nuclear power plants (summary report of the 367th RSK meeting), the RSK arrived at the conclusion to recommend some measures by way of precaution, in view of the great safety significance of the event, which, above all, intensify the controls with regard to leakages and corrosion phenomena.

The discussion of the drafts on ageing management was continued. For the updates of the RSK guidelines, the RSK discussed the surveys submitted by its committees and interfaces regarding future contributions of the Commission on Radiological Protection (SSK). The discussions will be continued for both topics.

At this meeting, the RSK dealt with the need for revision of KTA 2201.1 "Design of Nuclear. Power Plants against Seismic Events; Part 1: Principles". In the view of the RSK, not all parts of this standard comply with the state of the art in science and technology. It therefore regards it as necessary to perform a revision of the standard dating back to the year 1990. One and half year ago, the RSK established the working group seismology of the RSK Committee on PLANT AND SYSTEMS ENGINEERING (AST) which investigated the need for revision as preparatory work for the RSK. On the basis of the results now submitted by the working group, the RSK started the discussion of a statement in which the need for revision of KTA 2201.1 will be presented in detail.
Further, the RSK continued its discussions on the preparation of a recommendation on ageing management. In another part of the meeting, the BMU project on the revision of the nuclear rules and regulations was discussed.

The RSK continued its discussions on the need for revision of KTA 2201.1 "Design of Nuclear. Power Plants against Seismic Events; Part 1: Principles" and concluded it with the adoption of a statement on the revision of this standard.

The BMU plans a first discussion as of autumn 2004 of the results of a BMU project on the revision of the nuclear rules and regulations that will be available until then. At the meeting, the RSK prepared its proceeding for this discussion.

At this meeting, the RSK discussed first of all internal issues. This was followed by an in-depth discussion of further chapters of the RSK recommendation on ageing management at nuclear power plants, which is at issue. The discussions on this recommendation shall be concluded at the 374th meeting. Regarding the requirements on the verification of the effective emergency core cooling during loss-of-coolant accidents involving the release of insulation material, the RSK discussed the currently available results of its Committee on PLANT AND SYSTEMS ENGINEERING (AST). Also in this case, a conclusion of the discussions and adoption of a statement is expected in the near future.