Radiological environmental assessment of the recycle of LMFBR advanced fuels

The environmental impact resulting from the release of radioactive material during reprocessing and refabrication of spent LMFBR advanced fuels was compared with that from similar treatment of reference oxide fuel. Candidate advanced fuels include carbide ((U,Pu)C) in addition to nitride ((U,Pu)N) with selected concentrations of /sup 15/N. Several techniques for preparing enriched /sup 15/N were reviewed and estimates were made of the cost of preparing nitrogen enriched to greater than 99 percent by each method. Core neutronics, fuel management, and designs appropriate for each fuel were used with the ORIGEN code to calculate the compositions of spent core and blanket fuel. The mass of fuel recycled annually was that providing 50 GW(e)-years of energy at the burnup attained by each fuel. Confinement factors for each isotope were identified for reprocessing and refabrication operations and were used to calculate source terms describing isotopic release rates. These source terms were used in the AIRDOS-II code to estimate the 50-year dose to the maximally exposed individual and to both the local and world populations. Total body dose commitments to the maximally exposed individual for oxide and carbide fuels are about 2.8 millirem, while nitride fuel would result in a range of 59 to 3.4 millirem as the /sup 14/N content in fresh fuel is varied from 99.64 percent to zero

Whiplash following rear end collisions: a prospective cohort study

Objective: The purpose of this study was to investigate the factors which predict neck pain initially and at 1 year following a rear end collision. Methods: All people who reported a rear end collision to the Devon and Cornwall Constabulary were identified and formed the basis of the cohort. People were excluded if they were under 18 years of age or had suffered a head injury. The main outcome measures were neck pain lasting for more than a week after the accident and neck pain at least 1 day a week at 1 year. Logistic regression was used to investigate associations between demographic and accident related variables and outcomes. Results: A total of 1147 people reported rear end collisions to the police during the study period and 503 (44%) agreed to take part in the study. Of the respondents, 78% had neck pain lasting for more than a week and 52% still had pain at 1 year. Age (odds ratio, 95% confidence interval: 0.957, 0.942–0.972) and prior history of neck pain (8.32, 2.89–23.89) were the most important predictors of early neck pain. The most important predictors of pain at 1 year were the initial neck visual analogue scale (VAS) score (1.03, 1.01–1.05) and the presence of a compensation claim (4.09, 1.62–10.32). There was only weak evidence that measures of the severity of the impact were associated with outcomes. Conclusion: Demographic variables and the presence of a compensation suit show the strongest correlation with acute and chronic neck pain following rear end collisions

Incidence and outcome of subarachnoid haemorrhage: a retrospective population based study

OBJECTIVES—The purpose was to define the incidence and case fatality rates of subarachnoid haemorrhage in the population of Devon and Cornwall.
METHODS—A retrospective population based design was employed with multiple overlapping methods of case ascertainment. A strict definition of subarachnoid haemorrhage was used. Age and sex specific incidence rates and relative risks for death at different time intervals are calculated.
RESULTS—Eight hundred cases of first ever subarachnoid haemorrhage were identified; 77% of cases were verified by CT, 22% by necropsy, and 1% by lumbar puncture. The incidence rates are higher than those previously reported in the United Kingdom. The age standardised incidence rate (/100 000 person-years) for females was 11.9 (95% confidence interval (95% CI) 9.5-15.0), for males 7.4 (5.4-10.0), and the total rate was 9.7 (7.5-12.6). The case fatality rates at 24 hours, 1 week, and 30 days were 21 (18-24)%, 37 (33-41)%, and 44 (40-49)% respectively. The relative risk for death at 30days for those over 60 years:under 60 years was 2.95 (2.18-3.97).
CONCLUSION—The incidence of subarachnoid haemorrhage in the United Kingdom is higher than previously reported. Three quarters of the mortality occurs within 3days.


Incidence of brain tumours in two English counties: a population based study

OBJECTIVE—To define the incidence of brain tumours in Devon and Cornwall and to discover which case finding methods are the most fruitful. To examine what happens to patients after the diagnosis of a brain tumour.
METHODS—The primary method of case ascertainment was a review of all CT with contrast and MRI of the head performed on the population of Devon and Cornwall between 1 April 1992 and 31 March 1997.Secondary sources included registrations with the South and West Cancer Intelligence Unit and a search for all patients either admitted to hospital with a brain tumour or operated on for a brain tumour during the same period.
RESULTS—16 923 scans were reviewed of which 8774 (52%) were normal. The scan review found 2483 incident intracranial tumours, of which 861 were metastases. Secondary sources of case ascertainment disclosed 46 further cases. Cases were missed by the scan review mainly for technical reasons and only three patients were found who were diagnosed by non-imaging methods. The incidence of primary intracranial tumours standardised to the population of England and Wales was higher than any previously reported (21.04 (17.18-25.62)/100 000person-years). Overall, 21% of cases were not admitted to hospital. The categories least likely to be admitted were those with sellar and cranial nerve tumours. Those not admitted to hospital were significantly older than those who were.
CONCLUSION—One fifth of patients are not admitted to hospital after the diagnosis of a brain tumour and incidence studies must use case finding methods which will capture these cases. An audit of imaging results provides almost complete case ascertainment. This study shows that the incidence of primary brain tumours is considerably higher than previously thought. Official figures from the cancer intelligence units significantly underestimate brain tumour incidence, especially for benign tumours.