{"data":{"id":"us/10-cfr-71.51","jurisdiction":"us","citation":"10 CFR 71.51","heading":"Additional requirements for Type B packages.","body":"(a) A Type B package, in addition to satisfying the requirements of §§ 71.41 through 71.47, must be designed, constructed, and prepared for shipment so that under the tests specified in:\n(1) Section 71.71 (“Normal conditions of transport”), there would be no loss or dispersal of radioactive contents—as demonstrated to a sensitivity of 10−6 A2 per hour, no significant increase in external surface radiation levels, and no substantial reduction in the effectiveness of the packaging; and\n(2) Section 71.73 (“Hypothetical accident conditions”), there would be no escape of krypton-85 exceeding 10 A2 in 1 week, no escape of other radioactive material exceeding a total amount A2 in 1 week, and no external radiation dose rate exceeding 10 mSv/h (1 rem/h) at 1 m (40 in) from the external surface of the package.\n(b) Where mixtures of different radionuclides are present, the provisions of appendix A, paragraph IV of this part shall apply, except that for Krypton-85, an effective A2 value equal to 10 A2 may be used.\n(c) Compliance with the permitted activity release limits of paragraph (a) of this section may not depend on filters or on a mechanical cooling system.\n(d) For packages which contain radioactive contents with activity greater than 10 5 A2, the requirements of § 71.61 must be met.","path":["Title 10—Energy","CHAPTER I—NUCLEAR REGULATORY COMMISSION","PART 71—PACKAGING AND TRANSPORTATION OF RADIOACTIVE MATERIAL","Subpart E—Package Approval Standards"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-10.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:24:09Z","sha256":"0c85a810a96c7ab5c64a7c571297b410f255a4151aede4a9089541b21d714595","source_id":"us-cfr","stale":true,"prev":"us/10-cfr-71.47","next":"us/10-cfr-71.53"},"notice":"GroundRules: Original legal text. Not legal advice."}