Sunday, March 13, 2011

Can Nuclear Power Plants on Taiwan Withstand Earthquakes and Tsunamis?

Can Nuclear Power Plants on Taiwan Withstand Earthquakes and Tsunamis?
China Times editorial (Taipei, Taiwan, ROC)
A Translation
March 14, 2011

Japan has experienced an "earthquake of the century" measuring 9,0 on the Richter Scale. Its destructive power was terrifying, and captured the world's attention. Two nuclear power plants along the coast, in Fukushima Prefecture, suffered tsunami damage. This is the first time in history that a nuclear power plant has suffered severe damage from an earthquake and tsunami. Did its safety features work as intended? As of today, the eastern Japan earthquake has been the only real world test of nuclear safety measures against natural disasters.

Fukushima Nuclear Power Plants One and Three face the most serious threat. They are in danger of level one reactor core meltdowns. Once this happens, no one can predict how far the radioactive contaminants might spread. The Japanese government has expanded the size of the evacuation zone, from ten kilometers from to twenty kilometers. It has evacuated hundreds of thousands of residents. But that number is about to increase.

This was a super earthquake. The public on Taiwan is particularly sensitive to the dangers of earthquakes. Taiwan too is in a seismic zone. Taiwan too has three nuclear power plants close to the sea. Following the east Japan earthquake, a tsunami warning was issued for Taiwan's northeastern coast. This is where Nuclear Plants One and Two are located. As a result the public is deeply concerned about the spread of radioactive contaminants. They hope radioactive contaminants will not spread to Taiwan. The prospecgt has provoked controversy, and received substantial media coverage.

At one time the Three Mile Island nuclear incident in the US, and the Chernobyl nuclear disaster in the former Soviet Union commanded the media's attention. But distinctions must be made. The Three Mile Island reactor core did in fact melt down. But the power plant's safety provisions contained the radioactive contaminants within the structure. No contaminants leaked or affected local residents. The Chernobyl nuclear power plant on the other hand, had a completely different design. It was unlike most Western-style nuclear power plants. The biggest difference was a highly flammable graphite reactor core, instead of a design enabling containment and defense in depth. Human negligence also contributed to the catastrophic explosion. Large amounts of radioactive contaminants were released. An estimated 30 million people were affected.

Now compare the three nuclear power plants on Taiwan with Fukushima Nuclear Plants One and Three. All three are Boiling Water Reactors. All three have the same basic design. But the power plants at Fukushima were built in the 1950s. Nuclear Plants Number One and Two on Taiwan were built during the 1970s and 1980s. Twenty to thirty years of improvements, resulted in a more secure design and better construction materials.

Their safety concepts and design features may be very different. But the Fukushima Nuclear Power Plant teaches us an important lesson about nuclear power generation on Taiwan. Violent and sudden changes have occurred in the earth's climate. Earthquake intensity has steadily increased. Huge earthquakes of magnitude seven, eight, or even nine on the Richter Scale are now common. Will nuclear power plants built according to the old seismic design standards still hold up? After 20 or 30 years of operation, are these power plants still as safe as they were when originally designed?

Nuclear power plants on Taiwan must face another problem. We have detailed records for natural disasters. But we lack information tsunamis. The current nuclear power plants were designed to resist 12 meter high waves. But the south Asian tsunami waves already exceeded this height. And no one can guarantee that no more earthquakes or tsunamis will occur in the future. In fact, the probability is high. Government agencies must conduct detailed reviews, and establish detailed preventive measures, in advance.

The east Japan earthquake has once again demonstrated Japanese self-restraint and calm in the face of disaster. Ten to twenty million people were evacuated. Traffic in the disaster area was blocked the entire night. But no one lost his patience or sounded his horns. One could not characterize it as orderly. But few traffic disputes or arguments occurred. Such behavior is an indicator of national character. It is also the result of public understanding and peacetime training.

On Taiwan, by contrast, nuclear power plant disaster exercises are just that -- exercises. No one takes them seriously. No one engages in genuine disaster relief efforts. Frankly, many members of the public merely show up for free lunches and to party. Admittedly the public has never attached much importance to these exercises. But government agencies have also failed to promote them properly, They have failed to make the public aware of the importance of disaster prevention. They have failed to inculcate disaster prevention awareness.

Nuclear safety on Taiwan must take into account the other side of the Taiwan Strait. Mainland China currently has a dozen nuclear power plants in operation. Most are located on the southeast coast. Over ten are currently under construction. The two sides are close. They often share the same weather system. In the event of a radiation leak, it is likely they will affect each other. Domestic experts have long called for the establishment of a nuclear safety reporting system, as soon as possible. Such a system must be established, even if it is never used. Alas, this "technical" problem is something the two sides never discuss.

The Japanese have long maintained high standards for industrial safety. Its nuclear safety record in particular, has been exemplary. But in recent years, a string of human errors have led to nuclear safety accidents. Japan's safety record has been shattered. Today, Japan faces a nuclear disaster, caused by a natural disaster. It is testing the resilience and self-confidence of the Japanese people. A neighboring nation has suffered a misfortune, We empathize with its people. The government and public must also acquire a new understanding of nuclear safety. All aspects of nuclear safety, including psychology, design specifications, and security systems, must be bolstered. If we fail to do everything humanly possible, then we cannot place all the blame on natural disasters.

中國時報  2011.03.14
台灣核電廠頂得住巨震海嘯嗎?
本報訊

 日本發生芮氏規模九.○的百年巨震,在強大而恐怖的摧毀力量之後,更令世界關注的,是災區之一福島縣沿海兩座遭海嘯破壞的核電廠。這是世界核能發電史以來,第一次有核電廠在地震、海嘯中嚴重損毀,當初各種安全設計是否能發揮作用,東日本大地震成為至今唯一的多重天災與核安的實地測驗。

 目前福島核電廠一號機、三號機都面臨最嚴重的核災等級─爐心融毀。一旦發生這種情形,輻射汙染程度與如何擴大,沒人能預料。日本政府對當地居民的撤離範圍,也由十公里擴大到廿公里,疏散數十萬人,而且還會再增加。

 對於這起超級震災,台灣人民特別有感。台灣也是多震帶,也有三座核電廠位於海邊;東日本大地震發生後,海嘯警報範圍一度包括台灣東北沿岸,就是核一、二廠所在地。因此民眾高度關切是否有輻射汙染物質外洩、輻射落塵會不會飄到台灣等,成為熱門話題,媒體也大幅報導。

 一時間,美國三哩島核災、前蘇聯車諾比核電廠核災的字眼充斥媒體。要區分清楚的是,即使三哩島發生了真正的爐心融毀,但因電廠安全設計,所有輻射汙染物被圍阻在廠內,沒有外洩影響居民。而車諾比核電廠設計更與西方式核電廠完全不同,最大差異是,不但沒有圍阻體與層層深度防禦設計,爐心還是易燃的石墨材質,加上人為疏忽才會釀成爆炸巨災,大量輻射汙染物外洩,受災人數估計超過卅萬。

 再比較我國的三座核電廠與福島一、三號機,雖然都是沸水式反應爐,基本設計原理相同,但福島核電廠興建於一九五○年代,我國的核一、二廠建於七○與八○年代,經過廿到卅年的改善,安全設計與材質要求都更高。

 儘管安全理念與設計有很大不同,但福島核電廠對台灣及所有核能發電國家最大的啟示是,如今的地球處於氣候暴烈驟變期,地震強度一個比一個大,規模七、八、九的巨震屢見不鮮。現有核電廠當年的抗震設計,真頂得住嗎?在經過廿、卅年的運轉後,電廠是否仍能維持當年設計的安全係數?

 台灣的核電廠必須面對的另一個問題是,我國的災難史紀錄中,一直缺乏海嘯的資料,目前的核電廠是以十二公尺大浪為安全設計。但南亞海嘯引起的浪高已經超過這個設計,而沒有人可以保證未來不會有更大的地震或海嘯─事實上,機率頗高─政府有關單位也有必要就此深入檢討,及早擬定防範措施。

 此外,在這次東日本大地震中,我們再一次看到日本人面對災難時的克制與冷靜。十幾廿萬人的疏散過程中,災區交通塞整夜,但沒有人聽到因不耐等待而發出的喇叭噪音;雖不能說是井然有序,也鮮少看到爭道糾紛與爭吵。這樣的表現,是民族性,也是民眾對災難的了解與平時訓練所致。

 反觀國內,每次核電廠舉行防災「演習」,都像在「演戲」,現場完全看不到嚴肅防災,確實執行救災的畫面。坦白說,很多民眾也抱著「領便當」的心情客串上場。這固然因為國人向來不重視各種演習,但相關單位平時疏於有效宣導,無法讓民眾感受到防災的重要、進而建立防災意識有關。

 台灣的核安還要顧及對岸因素。目前大陸運轉中的核電廠有十幾處,多在東南沿海,興建中也超過十處。而兩岸緊鄰、常屬同一個天氣系統,一旦發生輻射外洩事件,互相影響的機率極高。國內專家早就呼籲,盡速建立核安通報系統,備而不用。但這種「技術」問題,似乎從來就不是雙方會談的重點。

 日本人對工業安全的要求向來維持高標準,核安方面更是模範生。但近年因陸續發生幾次人為操作疏失的核安意外,這個紀錄已經被打破。如今又面臨自然災害造成的核災變,在在考驗日本人的應變能力與信心。面對鄰國的不幸,我們除了感同身受,政府和民眾對核安都要有重新的認知,從心理、設計規範、安檢制度各方面加強;不盡人事,就不能全怪天災了。

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