Featured Research

from universities, journals, and other organizations

Hiroshima Porcelain Pieces Provide Insight Into Exposure Levels

Date:
March 27, 2002
Source:
Geological Society Of America
Summary:
Scientists are still studying the after-effects of the nuclear disaster caused by an atomic bomb dropped on Hiroshima on August 6, 1945. The amount of neutron fluence, for example, has been calculated from the site to establish what might be a safe level of exposure for humans. (Neutron fluence is the number of neutrons from the blast found per square centimeter.) The advent of nuclear accidents such as Three Mile Island and potential nuclear accidents in the future makes accurate information imperative. But scientists have recently realized that there are discrepancies in earlier estimates and have been looking for ways to resolve them. According to the latest research, the standards for a safe level of exposure to humans might be too conservative.

Scientists are still studying the after-effects of the nuclear disaster caused by an atomic bomb dropped on Hiroshima on August 6, 1945. The amount of neutron fluence, for example, has been calculated from the site to establish what might be a safe level of exposure for humans. (Neutron fluence is the number of neutrons from the blast found per square centimeter.) The advent of nuclear accidents such as Three Mile Island and potential nuclear accidents in the future makes accurate information imperative. But scientists have recently realized that there are discrepancies in earlier estimates and have been looking for ways to resolve them. According to the latest research, the standards for a safe level of exposure to humans might be too conservative.

Analyzing the neutron-induced fission tracks on certain objects found in Hiroshima enables scientists to calibrate the nuclear fluence. Geologist Robert L. Fleischer (Union College in New York), S. Fujita (Radiation Effects Research Institute in Japan), and M. Hoshi (Research Institute for Nuclear Medicine and Biology in Japan) have published their findings on a glass button found near ground zero in Hiroshima in the Health Physics Society Journal.

More recently, Union College geology student Jonathan MacDonald joined the team to determine the track density of fission tracks in porcelain fragments that were also found near ground zero. This study complements the previous work.

“At face value, these results are fluence values from a specific bomb event that will hopefully never be used again. These fission events occurred when thermal neutrons from the bomb caused fission in the normal trace amounts of uranium in the material,” MacDonald explained. “We determined the track density on the exterior glaze (glass), on the outside of one porcelain fragment and in a cross section of the glaze in another.”

While the value of the one sample nearly matches the previous estimates, the other one is 2 to 2.5 times higher. MacDonald will report the new values at the Geological Society of America’s North Eastern Section Meeting on March 25.

“If correct, the latter value may be important for regulation of human exposures in the U.S., because many of the current regulations are based on theoretical calculated values,” MacDonald said. “If this latter dose is correct—being higher than what is currently assumed—then the current standards should be less restrictive.”


Story Source:

The above story is based on materials provided by Geological Society Of America. Note: Materials may be edited for content and length.


Cite This Page:

Geological Society Of America. "Hiroshima Porcelain Pieces Provide Insight Into Exposure Levels." ScienceDaily. ScienceDaily, 27 March 2002. <www.sciencedaily.com/releases/2002/03/020327072750.htm>.
Geological Society Of America. (2002, March 27). Hiroshima Porcelain Pieces Provide Insight Into Exposure Levels. ScienceDaily. Retrieved July 24, 2014 from www.sciencedaily.com/releases/2002/03/020327072750.htm
Geological Society Of America. "Hiroshima Porcelain Pieces Provide Insight Into Exposure Levels." ScienceDaily. www.sciencedaily.com/releases/2002/03/020327072750.htm (accessed July 24, 2014).

Share This




More Matter & Energy News

Thursday, July 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

TSA Administrator on Politics and Flight Bans

TSA Administrator on Politics and Flight Bans

AP (July 24, 2014) TSA administrator, John Pistole's took part in the Aspen Security Forum 2014, where he answered questions on lifting of the ban on flights into Israel's Tel Aviv airport and whether politics played a role in lifting the ban. (July 24) Video provided by AP
Powered by NewsLook.com
Creative Makeovers for Ugly Cellphone Towers

Creative Makeovers for Ugly Cellphone Towers

AP (July 24, 2014) Mobile phone companies and communities across the country are going to new lengths to disguise those unsightly cellphone towers. From a church bell tower to a flagpole, even a pencil, some towers are trying to make a point. (July 24) Video provided by AP
Powered by NewsLook.com
Algonquin Power Goes Activist on Its Target Gas Natural

Algonquin Power Goes Activist on Its Target Gas Natural

TheStreet (July 23, 2014) When The Deal's Amanda Levin exclusively reported that Gas Natural had been talking to potential suitors, the Ohio company responded with a flat denial, claiming its board had not talked to anyone about a possible sale. Lo and behold, Canadian utility Algonquin Power and Utilities not only had approached the company, but it did it three times. Its last offer was for $13 per share as Gas Natural's was trading at a 60-day moving average of about $12.50 per share. Now Algonquin, which has a 4.9% stake in Gas Natural, has taken its case to shareholders, calling on them to back its proposals or, possibly, a change in the target's board. Video provided by TheStreet
Powered by NewsLook.com
Robot Parking Valet Creates Stress-Free Travel

Robot Parking Valet Creates Stress-Free Travel

AP (July 23, 2014) 'Ray' the robotic parking valet at Dusseldorf Airport in Germany lets travelers to avoid the hassle of finding a parking spot before heading to the check-in desk. (July 23) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins