For the first time in a long time, the fog began to lift around the fatal accident, which completely and permanently disabled PAVETS “Chaira”. The pumped-storage hydropower plant, which is unique in terms of its scale and importance for the national electricity system, “catastrophized” in March 2022 under strange circumstances – during a start-up test after the major repair of one of the four hydro units had been completed.
The damage turned out to be so serious that since then the entire plant has been shut down, inspections, investigations and analyzes are ongoing. But on Thursday in the National Assembly, the Minister of Energy Rumen Radev revealed shocking facts, explaining at least to some extent why the serious accident happened. Radev was summoned to a hearing to acquaint the deputies with the situation.
One of Bulgaria’s key energy facilities – PAVETS “Chaira” will remain out of order for a long time.
It turns out that PAVETS “Chaira” has been severely exploited over the years, working in overload modes to “balance” the multiplying RES plants – solar and wind. This powerful underground water power plant, executed according to a unique innovative project of the Japanese “Toshiba” and put into operation in the 90s of the last century, was actually conceived mainly as a “substitute” for the Kozloduy NPP (during planned repairs and emergency stops), and not to be used as a buffer during the frequent changes in the production of photovoltaics and fins. The “squeezing” of the possibilities of the Chaira PAVEC was particularly intense in the period 2016-2019 (when there was a boom in the connection of RES capacities). This became clear from the minister’s words.
Even his predecessor from the official office, Rosen Hristov, claimed that one of the possible reasons for the serious accident during the start-up of the rehabilitated fourth hydro unit was “fatigue of the metal”. In practice, the current minister also confirms this version. What “fatigue” – it is known that the metal used in PAVETS “Chaira” should have a life of 60 years, not 30, expressed amazement of an MP. In this connection, Rumen Radev explained that probably due to the excessive load on the plant, the metal has worn out ahead of schedule and huge cracks have opened in places on the “stator columns”.
Minister Radev also revealed another shocking fact – the mandatory periodic basic inspections and repairs of the Chaira Pavement Plant were skipped and delayed by five years. The capacities launched in the 1990s had to be inspected and rehabilitated every 12 years. Instead, the first large-scale survey in terms of volume and scope was conducted in 2013, and the repair and restoration works did not start until 2019, Rumen Radev explained to the deputies.
After the serious accident of March 2022, inspections and conversations were held with numerous companies and experts, incl. with representatives of “Toshiba”, the project’s insurer and energy consultants. Everyone was of the opinion that the accident at the Chaira PAVEC was without precedent and that technological solutions should be sought that have not been applied anywhere so far, the minister said.
The details presented by Radev add to the suspicions of corruption during the repairs and sabotage of the plant’s work and another nuance – the accident happened because of long-standing criminal negligence of the people who managed the Bulgarian energy industry, NEK and PAVETS itself. The intelligence services are churning out all kinds of versions, but so far it is not known what they found. nia.
When asked by a member of parliament if there is any evidence that the accident was caused by faulty software and who wrote the programs, the minister said that he was not prepared to answer and would check further. Asked why the rehabilitation, which began in 2019 under the management of GERB, was awarded not to the equipment manufacturer Toshiba, but to a “Romanian garage company”, he explained that there was a public contract won by the ABB&VoIth Hydro consortium, and the entire procedure took place under the control of the Kozloduy International Fund and the European Bank for Reconstruction and Development, which participated in the financing.
Radev nevertheless brought a dose of optimism into the gloomy picture – he announced that there is already a road map for the repairs of each of the units and that next week the Swiss company that analyzes the causes and circumstances surrounding the accident is expected to present its report and conclusions.
For a fourth unit, however, it will be necessary to supply new equipment.
The minister’s forecast for the necessary funds surprised the people’s representatives. According to him, the necessary sum for the repairs plus the new equipment will be less than BGN 100 million, while earlier the acting minister Rosen assumed that about BGN 2 billion would be needed.
The road map
First stage, hydro unit 1
The repair and restoration activities will be carried out by “Toshiba”, and the company is expected to submit a binding offer. (Work meetings and site visits were held between NEK and representatives of the company. The possibilities for restoring the turbine and the scope of the necessary repair activities were discussed.)
Second stage, hydro unit 2
An annex to the main rehabilitation contract has been concluded and a technical study is underway to modify the unit, which will allow it to be returned to work for a limited period of time.
Third stage, hydro unit 3
Its rehabilitation has been completed according to the current contract, with partial tests of the systems and facilities. However, operations have been suspended pending the determination of the cause of the accident with hydro unit 4 last March. If the modification of the second unit is successful, it will be applied to the third as well.
Fourth stage, hydro unit 4
A “root cause” analysis is being conducted to determine the root cause of the March 22, 2022 incident. Metal samples have been sent to a licensed metallurgical laboratory at the Technical University of Stuttgart, Germany. Until now, studies have been carried out on the composition and strength indicators of the material of the stator columns, a digital model has been prepared and the hydraulic processes in the hydro unit have been analyzed. Low-cycle strain-controlled fatigue tests were performed on the material.
If you want to support independent and quality journalism in “Sega”,
you can donate via PayPal
2023-11-18 11:09:49
#Minister #Radev #revealed #scandalous #facts #collapse #Chaira #Pavement
