HSE's safety assessment principles for criticality safety.

The Health and Safety Executive (HSE) published its revised Safety Assessment Principles for Nuclear Facilities (SAPs) in December 2006. The SAPs are primarily intended for use by HSE's inspectors when judging the adequacy of safety cases for nuclear facilities. The revised SAPs relate to all aspects of safety in nuclear facilities including the technical discipline of criticality safety. The purpose of this paper is to set out for the benefit of a wider audience some of the thinking behind the final published words and to provide an insight into the development of UK regulatory guidance. The paper notes that it is HSE's intention that the Safety Assessment Principles should be viewed as a reflection of good practice in the context of interpreting primary legislation such as the requirements under site licence conditions for arrangements for producing an adequate safety case and for producing a suitable and sufficient risk assessment under the Ionising Radiations Regulations 1999 (SI1999/3232 www.opsi.gov.uk/si/si1999/uksi_19993232_en.pdf).

HSE's Safety Assessment Principles for radiation protection.

The Health and Safety Executive (HSE) published its revised Safety Assessment Principles for Nuclear Facilities (SAPs) in December 2006. The SAPs are primarily intended for use by HSE's inspectors when judging the adequacy of safety cases for nuclear facilities. The revised SAPs refer in part to HSE's expectations relating to the technical discipline of radiation protection. The purpose of this paper is to describe for the benefit of a wider audience HSE's reasoning behind the final published SAPs and to set out the purpose of each specific radiation protection (RP) principle. The paper also discusses principles in other sections of the SAPs which are relevant to radiation protection. The paper notes that the SAPs should be viewed as a reflection of good practice in relation to nuclear facilities in the context of interpreting relevant parts of primary legislation such as the Nuclear Installations Act 1965.

A single amino acid substitution in the viral polymerase creates a temperature-sensitive and attenuated recombinant bovine parainfluenza virus type 3.

Bovine parainfluenza virus type 3 (bPIV3) is under development as a live virus vaccine vector. The RNA genome of a recombinant bPIV3 harbored four nucleotide changes, one of which resulted in a mutation of the viral polymerase (A. A. Haller et al., 2000, J. Virol. 74, 11626-11635). The contribution of this conservative amino acid substitution (I1103V) in the polymerase to the temperature-sensitive and attenuation phenotypes of r-bPIV3 was investigated by creating a new virus, r-bPIV3(I), that expressed the wild-type polymerase. r-bPIV3(I) was not temperature-sensitive for growth in vitro and the replication of r-bPIV3(I) was no longer restricted in hamsters. The effect of the amino acid substitution in the polymerase was also studied in a chimeric bovine/human PIV3, a virus that displayed temperature-sensitive and attenuated phenotypes (A. A. Haller et al., 2000, J. Virol. 74, 11626-11635). It was not clear whether these defects were due to the impaired polymerase or the replacement of the bPIV3 surface glycoproteins with those of hPIV3. The results showed that the altered polymerase was indeed responsible for the temperature-sensitive phenotype of bovine/human PIV3 but did not appear to play a role in the attenuation phenotype.

Immunity to rubella in prepubertal girls in Prince Edward Island.

A survey of rubella immunity was conducted among prepubertal girls in Prince Edward Island. Of the 431 girls enrolled in grade 4 in a random sample of schools 83% had a school record of having been vaccinated after their first birthday. A screening test of finger-prick samples revealed that 95% of the girls with a written history of vaccination after their first birthday were immune, 79% of those vaccinated before their first birthday or for whom the date of vaccination was uncertain were immune, and 40% of unvaccinated girls were immune. Of the 49 susceptible girls 43 were vaccinated; all but 2 were found to be immune on retesting. The findings support the recommendation of the National Advisory Committee on Immunization to vaccinate all prepubertal girls without a written history of rubella vaccination after their first birthday.