O.E.C.D. HALDEN REACTOR PROJECT FOURTH ANNUAL REPORT, 1962
During the first quarter of 1962, the modification and preparatory work for operation on the second fuel charge was completed, and the research program on the second core was started in March. A low power program was subsequently carried out to measure the excess reactivity, control rod effectiveness, and void andd temperature reactivity coefficients. The reactor was brought up to a power level of 15 Mw during October, 1962. The first power measurements with the reactor were aimed at determining its transient characteristics by perturbing reactivity and steam load demand. From these messurements it was found that the reactor was very sensitive to perturbations in which the nuclear power is reduced below the power being removed by the primary heat exchangers. It was found that negative power transients were caused by moderator boiling. Since the moderator of HBWR is working at close to saturation temperature, even a small decrease in moderator pressure will result in moderator boiling. As a result of moderator flashing, the reactor wss actually found to be divergently unstable at power levels above 17 Mw at maximum subcooling. In the development of a theoretical model for describing the observed instability, the uncertainties in rate of formation and distribution of flashing steam bubbles have, due to lack of experimental data, been treated parametrically in order to obtain agreement with the reactor observations. Since the long range goal of the Halden program is to assess the characteristics of large heavy-water boiling reactors, some preliminary investigation on the dynamic properties of large reactors were initiated. An analytical solution was found to the problem of space dependent kinetics. The development and in-core testing of instrumented fuel assemblies and the improvement of the data reduction system have required a major part of the development. An electrical test facility that would permit hydraulic investigations of the performance of both second charge fuel elements and new fuel elements was constructed. Test sections for the loop contain instruments identical to those used in-core. All experimental perturbation equipment was rebuilt for second charge pressures andd temperatures. The new sinusoidal reactivity oscillator performed satisfactorily at power after installation of a forced air cooling system. The reactivity step generator has undergone outof- pile commissioning. (auth)
- Research Organization:
- Norway. Institutt for Atomenergi. OECD Halden Reaktor Prosjekt
- NSA Number:
- NSA-18-003187
- OSTI ID:
- 4134047
- Report Number(s):
- NP-13301
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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