[en] This work comprises the results of investigations conducted in connection with the cessation of a near surface LILW repository at Kjeller, Norway. The nearly 1000 drums in the repository was retrieved in the autumn of 2001 after 31 years of storage within the clay barrier. The repository contained 80 GBq plutoinum, 2.5 Gbq uranium and more than 1 TBg each of 90Sr and 137Cs. Studies of the integrity of the clay barrier showed that with two minor exceptions no contamination were present outside of the repository. Typically the radioactive species that had leaked from the few damaged drums were contained in the 2 cm of clay closest to the drum surface. Investigations of the physical condition of one waste drum subjected to 23 years of repository storage showed that little or no degradation had taken place either in the concrete shielding or in the inner steel container material. Except from 20 drums set aside for further studies, the whole inventory of the near surface repository have now been transferred to the KLDRA-Himdalen repository and storage site. (author)

[en] By means of particle-γ coincidence measurements the decay modes for highly excited low spin states in some Dy isotopes have been investigated. We have studied also: couplings between two-quasiparticle states and vibration in the energy region from 1.5 to 2.5 MeV, non-statistical cooling in the energy region from 2.5 to 6.5 MeV, the neutron emission from threshold up to approximately 40 MeV of excitation. 9 refs., 15 figs. (author)

[en] The structure and decay properties of levels between 1 and 40 MeV of excitation energy in rare earth nuclei have been studied. In particular, coupling phenomena and signatures of non-statistical cooling are discussed. (orig.)

[en] Published in summary form only

[en] The strength function and the angular distribution of the high energy γ rays emitted by the giant dipole resonance (GDR) in hot rotating^109,110Sn nuclei have been measured at temperature T=1.8 MeV and at four values of the angular momentum I. The GDR width is ∼2 times larger than at T=0 and increases by ∼20% as I goes from 40 to 54ℎ. The a₂(E_γ) increases by a factor of ∼2. Based on these two facts and on the comparison with theory we conclude that large deformations driven by I and combined with shape and orientation fluctuations are responsible for the measured increases. Collisional damping is constant and practically equal to the T=0 case

[en] In a plunger experiment the mean life of the (νf₆²x3^-x3^-)12⁺ state at 3.981 MeV in ₆₄¹⁴⁸Gd₈₄ was measured at τ=83(10) ps, giving 77(11)B_W for the 1286 keV 12⁺→9^- E3 transition rate, confirming the double-octupole character of the 12⁺ state. The observed deviations in energy and transition rate from harmonic vibration are shown to be caused by the exclusion principle acting between nucleons in the two phonons and are related to the dominant contributions to the ¹⁴⁸Gd octupole phonon of the low-lying Δl=Δj=3 proton and neutron in-shell 3^- excitations which are of vital significance for the octupole mode in open-shell nuclei

[en] Substantial amounts of produced water containing elevated levels of ²²⁶Ra and ²²⁸Ra are discharged into the sea as a result of oil and gas production on the Norwegian continental shelf. The average concentration in the discharges is 3.3 and 2.8 Bq/L of ²²⁶Ra and ²²⁸Ra, respectively. The main objective of the project described in the paper is to establish radiological safe discharge limits for radium, lead and polonium in produced water produced by oil and gas installations on the Norwegian continental shelf. One of the objectives of the study is to provide information to enable risk assessment based on doses from ionizing radiation to marine biota and man. Reference organisms for the North Sea area have been chosen for calculation of absorbed dose to biota. The dose calculations rely on specific knowledge of activity concentration in the reference organism, activity concentration in seawater and sediments, dose conversion factors and time spent at different locations relative to the point of discharge. Based on the calculated doses to marine biota, 'potential no effect concentrations' are recommended. (author)

[en] In a plunger experiment the mean life of the (ν f₆²x3^-x3^-)12⁺ state at 3.981 MeV in ₆₄¹⁴⁸Gd₈₄ was measured as τ=83(10)ps, giving 77(11)B_w for the 1286 keV 12⁺ → 9^- E3 transition rate, which confirms the double-octupole character of the 12⁺ state. The observed deviations in energy and transition rate from harmonic vibration are shown to be caused by the exclusion principle acting between nucleons in the two phonons and are related to the dominant contributions to the ¹⁴⁸Gd octupole phonon of the low-lying Δl=Δj=3 proton- and neutron in-shell 3^- excitations which are of vital significance for the octupole mode in open-shell nuclei. (author). 17 refs., 2 figs