AKW- Lebensdauer: von Bauteilen beschränkt

Nun hat die Regierung knurrend schliesslich die Übertragung von Restlaufzeitmengen aufgegeben.
Und dem schrittweisen Abschalten zu konkreten Terminen zugestimmt.




Was ist mit den Hintertüren ?
Warten wir einmal ab, welche Kröten das parlamentarische Verfahren noch hervorzaubert, bis die Tinte trocken ist.

Der Spiegel	Der Spiegel Wer profitiert also ? Was ist mit der Endlagerung ? Welche Summen wird die Regierung den Stromkonzernen noch anbieten, um sie zufrieden zu stellen ? Und was machen wir bis 2022 ? Ist das Risiko vor 2022 etwa geringer ? Sollen wir solange auswandern ? Wie ist das eigentlich mit der Lebensdauer von in den Steuerungen verwendeten Microchips, Halbleiterbauelemente ? Wie lang ist eigentlich die Speicherdauer der Programme, die in den Microkontrollern der Prozesssteuerungen von AKW ablaufen ? Welchen Einfluss hat die ionisierende Strahlung auf Speichererhalt und Lebensdauer der Chips ?  Wie verhalten sich die elektronischen Steuerungen im Falle einer Nuklearexplosion (EMP)? Nuclear reactors produce gamma radiation and neutron radiation which can affect sensor and control circuits in nuclear power plants. Nuclear explosions produce a short and extremely intense surge through a wide spectrum of electromagnetic radiation, an electromagnetic pulse (EMP), neutron radiation, and a flux of both primary and secondary charged particles. In case of a nuclear war they pose a potential concern for all civilian and military electronics.... Two fundamental damage mechanisms take place: Lattice displacement, caused by neutrons, protons, alpha particles, heavy ions, and very high energy gamma photons. They change the arrangement of the atoms in the crystal lattice, creating lasting damage, and increasing the number of recombination centers, depleting the minority carriers and worsening the analog properties of the affected semiconductor junctions. Counterintuitively, higher doses over short time cause partial annealing ("healing") of the damaged lattice, leading to a lower degree of damage than with the same doses delivered in low intensity over a long time. This type of damage is especially important for bipolar transistors, which are dependent on minority carriers in their base regions; increased losses caused by recombination cause loss of the transistor gain. See neutron effects. Ionization effects are caused by charged particles, including the ones with energy too low to cause lattice effects. The ionization effects are usually transient, creating glitches and soft errors, but can lead to destruction of the device if they trigger other damage mechanisms, e.g. a latchup. Photocurrent caused by ultraviolet and x-ray radiation may belong to this category as well. Gradual accumulation of holes in the oxide layer in MOSFET transistors leads to worsening of their performance, up to device failure when the dose is high enough; see total ionizing dose effects. The effects can vary wildly depending on all the parameters - the type of radiation, total dose and the radiation flux, combination of types of radiation, and even the kind of the device load (operating frequency, operating voltage, actual state of the transistor during the instant it is struck by the particle), which makes thorough testing difficult, time consuming, and requiring a lot of test samples. ... The sensitivity of the devices may increase together with increasing level of integration and decreasing size of individual structures. There is also the risk of induced radioactivity caused by neutron activation, which is a major source of noise in high energy astrophysics instruments. Induced radiation, together with residual radiation from impurities in used materials, can cause all sorts of single-event problems during the device's lifetime. GaAs LEDs, common in optocouplers, are very sensitive to neutrons.  Total ionizing dose effects: The cumulative damage of the semiconductor lattice (lattice displacement damage) caused by ionizing radiation over the exposition time. It is measured in rads and causes slow gradual degradation of the device's performance; total dose greater than 5000 rads delivered to silicon-based devices in seconds to minutes will cause long-term degradation. In CMOS devices, the radiation creates electron–hole pairs in the gate insulation layers, which cause photocurrents during their recombination, and the holes trapped in the lattice defects in the insulator create a persistent gate biasing and influence the transistors' threshold voltage, making the N-type MOSFET transistors easier and the P-type ones more difficult to switch on. The accumulated charge can be high enough to keep the transistors permanently open (or closed), leading to device failure. Transient dose effects: The short-time high-intensity pulse of radiation, typically occurring during a nuclear explosion. The high radiation flux creates photocurrents in the entire body of the semiconductor, causing transistors to randomly open, changing logical states of flip-flops and memory cells. While normal commercial-grade chips can withstand between 50 and 100 gray (5 and 10 krad), space-grade SOI and SOS chips can survive doses many orders of magnitude greater. Since radiation effects damage the memory content even when the system is not accessing the RAM, a "scrubber" circuit must continuously sweep the RAM; reading out the data, checking the parity for data errors, then writing back any corrections to the RAM. Nicht unbedingt Beruhigendes aus den AKW-Störmeldungen: "Aufgrund eines spontanen Fehlschließens des Volllastregelventils im Hauptspeisewasserstrang ..kam es ..zur auslegungsgemäßen Auslösung der Reaktorschnellabschaltung (RESA). Der Ablauf der automatischen Maßnahmen war bestimmungsgemäß und verlief störungsfrei... konnte der Fehler nicht reproduziert werden. Weitere Untersuchungen werden noch durchgeführt -" "Reaktorschutzsystem..Aufgrund eines ..aufgetretenen Fehlers ..konnte [Ventil]nicht geschlossen werden. ...Ursache des Fehlers im Einschub wird noch weiter untersucht.. dient der Verhinderung von Aktivitätsfreisetzung an die Umgebung...Der Betreiber hat es in die Stufe 0 der internationalen Bewertungsskala INES eingestuft" Quellen Wikipedia Freescale