Optimizing fuel cycle costs by increasing the final burnup leads to reduced generation of plutonium. Under properly defined boundary conditions thermal recycling in mixed oxide (MOX) fuel assemblies (FAs) reduces further the amount of plutonium which has to be disposed of in final storage. Increasing the final burnup requires higher initial enrichments of uranium fuel to be matched by an advanced design of MOX FAs with higher plutonium contents. The neutronic design of these MOX FAs has to consider the licensing status of nuclear power plants concerning the use of MOX fuel. The Siemens Nuclear Fuel Cycle Division, with more than 20 years' experience in the production of MOX fuel, has designed several advanced MOX FAs of different types (14 x 14 to 16 x 16) with fissile plutonium contents up to 4.60 w/o.

KARMEN denotes an experimental program of neutrino physics using a pulsed source of neutrinos νμ, νeandνμ with energies up to 52.8 MeV and a 56 t scintillation calorimeter. Major physics aims are the measurement of charged current (CC) as well as neutral current (NC) neutrino nucleus interactions on 12C with their implications for specific weak couplings, nuclear formfactors, μ-e universality and the search for neutrino oscillations νμ → νeandνeandνμ → νe. We present the results of the KARMEN experiment from its first two years of data taking.

The charged current nuclear transition C-12(nu(e), e-) N-12(g.s.) has been observed in the KARMEN experiment. The flux average cross section for nu(e) from mu+ decay at rest is determined to be [sigma] = [8.1 +/- 0.9(stat.) +/- 0.75(syst.)] x 10(-42) cm2. For the first time also the energy dependence of the cross section has been measured for neutrino energies up to 50 MeV.

The neutral current nuclear excitation 12(v,v′)12C∗ (1+, 1; 15.1 MeV) has been observed for the first time. For ve and vμ from μ+ -decay at rest the flux averaged cross section was determined to be <σNC(ve+vμ) > = [10.8±5.1 (stat.) ±1.1 (syst.)]×10−42 cm2.

KARMEN is a 56 t scintillation calorimeter designed for beam dump neutrino experiments at the neutron spallation facility ISIS of the Rutherford Appleton Laboratory. The calorimetric properties are demonstrated by cosmic muons and laser calibration. The measured energy resolution of the detector is σE/E ≈ 11.5%/√E[MeV], the position resolution σx = 5 cm and the timing resolution σt ≈ 350 ps.

An anticounter for the KARMEN experiment was built for effective suppression of background induced by cosmic muons. A special arrangement of 136 plastic scintillator sheets (NE 110, 3 cm thick) with 180° light coupling provides tight enclosure of the 56 t central calorimeter, reducing the leakage of the anticounter for cosmic muons to less than 1.5%.