Search Results

You are looking at 1 - 7 of 7 items for

  • Author or Editor: N. Wogman x
  • Refine by Access: All Content x
Clear All Modify Search

Summary  

In view of the terrorist threats to the United States, the country needs to consider new vectors and weapons related to nuclear and radiological threats against our homeland. The traditional threat vectors, missiles and bombers, have expanded to include threats arriving through the flow of commerce. The new commerce-related vectors include: sea cargo, truck cargo, rail cargo, air cargo, and passenger transport. The types of weapons have also expanded beyond nuclear warheads to include radiation dispersal devices (RDD) or “dirty' bombs. The consequences of these nuclear and radiological threats are both economic and life threatening. The defense against undesirable materials entering our borders involves extensive radiation monitoring at ports of entry. The radiation and other signatures of potential nuclear and radiological threats are examined along with potential sensors to discover undesirable items in the flow of commerce. Techniques to improve radiation detection are considered. A strategy of primary and secondary screening is proposed to rapidly clear most cargo and carefully examine suspect cargo.

Restricted access

Abstract  

The sensitivity of environmental sampling and analysis for the estimated atmospheric concentrations of radionuclides in effluents from clandestine nuclear facilities may require many sampling sites and exorbitant costs to monitor such large areas. An assessment has been made of the key factors necessary to support the operation of a nuclear facility, e.g., the existence of a nearby transportation network, main electrical power supply, and population centers. Screening, the subject of this paper, evaluates how cartographic data and satellite imagery can be used to identify areas most capable of supporting undeclared nuclear operations. As a result, large geographical areas can be eliminated from environmental monitoring and sampling. This leads to reduced costs, a reduction in the number of sampling sites required, and a reduction in the overall level of effort required to accomplish effective environmental monitoring. The screening methodology and techniques are described and examples given.

Restricted access

Abstract  

Nuclear proliferation signature radionuclides can be delivered to the aquatic environs via direct liquid discharges or atmospheric routes. The candidate radionuclides for detection are 3H, 90Sr, 95Nb, 95Zr, 99Tc, 106Ru, 125Sb, 129I, 134Cs, 137Cs, 144Ce, 147Pm, NatU, 238U, 235U, 237Np, 239Pu, 240Pu, and 241Pu. The criteria for detection are the limits of radionuclide analysis, the nature and variability of background oncentrations, and the transport characteristics between the source and sample site. The type of sample to be taken is determined by the signature radionuclides sorption on/in the media sampled. Non-sorbing radionuclides such as 3H, 99Tc, and 129I are in the water, whereas the Pu radionuclides are in the transported sediments. Results are discussed for monthly releases of radionuclides such as 90Sr, 137Cs, and 239Pu for variable flow-rate conditions with typical backgrounds and typical detection limits.

Restricted access

Abstract  

A method of prospecting for uranium and thorium is proposed based on uptake of their radioactive daughters226Ra and228Ra by plants, the collection of plant material by herbivores, the concentration of the radioactive species by specific animal tissues, and the subsequent gamma-ray analysis of the tissues.

Restricted access

Abstract  

A rare earth group separation scheme followed by normal Ge(Li), low energy photon detector (LEPD), and Ge(Li)−NaI(Tl) coincidence-noncoincidence spectrometry significantly enhances the detection sensitivity of individual rare earth elements (REE) at or below the ppb level. Based on the selected γ-ray energies, normal Ge(Li) counting is favored for140La,170Tb and169Yb; LEPD is favored for low γ-ray energies of147Nd,153Sm,166Ho and169Yb; and noncoincidence counting is favored for141Ce,143Ce,142Pr,153Sm,171Er and175Yb. The detection of radionuclides152mEu,159Gd and177Lu is equally sensitive by normal Ge(Li) and noncoincidence counting;152Eu is equally sensitive by LEPD and normal Ge(Li); and153Gd and170Tm is equally favored by all the counting modes. Overall, noncoincidence counting is favored for most of the REE. Precise measurements of the REE were made in geological and biological standards.

Restricted access

Abstract  

A seabed nuclear probe has been developed which permits the measurement of up to 33 elements at the parts per thousand to parts per million levels in continental shelf areas. The probe consists of a neutron irradiation source,252Cf, which neutron activates the elements in the minerals of interest. These resulting radioactive elements emit characteristic gamma radiation which is analyzed in situ in 2- to 10 min counting intervals with a Ge(Li) detector system. Details of the irradiation source, the Ge(Li) detector, and spectra taken in situ in a marine environment are discussed with respect to the detection of the minerals at concentrations of economic interest.

Restricted access

Summary  

The U.S. Department of Energy supports 24 fellowships for students to attend six-week programs at either San Jose State University in California, or Brookhaven National Laboratory (BNL) in New York. The American Chemical Society through the Division of Nuclear Science and Technology operates both schools. The twelve students at the BNL program are enrolled in the State University of New York at Stony Brook (SUNYSB) and receive 3 college credits for the lecture course (CHE-361) and 3 additional credits for the laboratory course (CHE-362). In addition to lectures and laboratories, students tour various nuclear facilities offsite, at BNL, and at SUNYSB. Opportunities are given the students to interact with faculty and scientists within the profession through the Guest Lecture Program. Further details are discussed along with results of student surveys for the years 1999 through 2002.

Restricted access