Stability measurements in the German nuclear power plant Wuergassen during cycle 14

Journal Article · Thu Dec 01 00:00:00 EST 1994 · Nuclear Technology; (United States)

OSTI ID:6985686

Pollmann, E ^[1]; Schulze, J; Kreuter, D ^[2]

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1. PreussenElektra, Beverungen (Germany). Kernkraftwerk Wuergassen
2. Siemens AG Offenbach (Germany)

In a boiling water reactor, nuclear-thermal-hydraulic instabilities can occur if extreme operating conditions prevail. In various nuclear reactors, stability measurements have been carried out during which the location and the shape of the stability threshold was measured at a certain exposure point during the cycle. Earlier sensitivity studies have already shown that fuel assembly parameters have only a small influence on stability compared with plant parameters. The influence of plant parameters has been verified by measurements that were carried out in the German boiling water reactor Wuergassen every 4 to 6 weeks during cycle 14. The results of the measurements showed for the single-loop operation point (least stable point in the core map) a strong variation of the stability threshold power during the cycle. From the beginning of cycle to the middle of cycle, the stability threshold power decreases by [approximately]16% (relative). After the minimum was reached, the stability threshold power increased again. Smaller variations of the stability threshold power in the core map at natural circulation indicate that not only the stability threshold varies during the cycle, but also the shape of the stability threshold is changed. Analyses with the code system STAIF have shown that the stability behavior during the cycle can clearly be correlated with the variation of the axial and radial power density profile due to control rod maneuvering and fuel burnup. Furthermore, it could be shown that for the estimation of the neutronic feedback not only the density coefficient must be taken into account but also the void variation caused by a power perturbation.

• OSTI ID: 6985686
• Journal Information: Nuclear Technology; (United States), Vol. 108:3; ISSN 0029-5450
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
WUERGASSEN REACTOR
REACTOR STABILITY
POWER DENSITY
REACTOR CORES
REACTOR SAFETY
S CODES
TRANSIENTS
VARIATIONS
BWR TYPE REACTORS
COMPUTER CODES
ENRICHED URANIUM REACTORS
POWER REACTORS
REACTOR COMPONENTS
REACTORS
SAFETY
STABILITY
THERMAL REACTORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
220900* - Nuclear Reactor Technology- Reactor Safety
210100 - Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled