ISO INTERNATIONAL STANDARD 26802 First edition 2010-08-01 Nuclear facilities Criteria for the design and the operation of containment and ventilation svstems for nuclear reactors Installations nucléaires- Criteres pour la conception et I'exploitation des systemes de confinement et de ventilation des reacteurs nucleaires Reference number ISO 26802:2010(E) @ISO 2010 py IHS under ted without license from IHS Not for Resale ISO 26802:2010(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The IsO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by IsO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHTPROTECTEDDOCUMENT @ISO2010 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, isO's member body in the country of the requester. ISO copyright office Case postale 56. CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland @ Iso 2010 - All rights reserved I without license from IHS Not for Resale ISO 26802:2010(E) Contents Page Foreword Introduction .vi 1 Scope 2 Normative references.. 3 Terms and definitions 4 Functions ensured by the ventilation system. .6 4.1 General 4.2 Main functions .. 5 Architecture and description of the different ventilation systems . .8 5.1 Ventilation of the volumes within the primary containment envelope ..8 5.2 Ventilationofthevolumeslocatedwithinthesecondaryconfinement. .10 5.3 Ventilation of the volumes located outside the secondary confinement. 10 5.4 Miscellaneous ventilation systems not connected with containment envelopes . 11 6 Safety aspects for ventilation systems .. 6.1 General principles... 6.2 Risk assessment procedure - -General. 12 6.3 Risk assessment procedure for severe accidents.. 14 7 Requirements for the design of ventilation systems.. 7.1 Confinement of radioactive material .. 16 7.2 Filtration ... 7.3 Reactor specificities.. 35 8 Management of specific risks .. 38 8.1 Control of combustible gases in the reactor building ... 38 8.2 Management of ambient conditions ..... 39 8.3 Prevention of risks linked to releases of heat, gases or toxic vapours . 41 8.4 Prevention of risks linked to the deposition of matter in ventilation ducts ... 41 8.5 42 8.6 Consideration of external hazards ... ..45 9 Dispositions concerning the management and the operation of the ventilation systems 9.1 Organization and operating procedures ... .46 9.2 Technical operating instructions... .46 9.3 Operational management issues .. 47 9.4 Test procedures and maintenance .47 9.5 Monitoring of the ventilation system... 50 9.6 Control of the ventilation system to prevent fire hazards.... 51 10 Control and instrumentation 53 10.1 10.2 Instrumentation .. 10.3 Alarms.... 54 Annex A (informative) Typical radioactive products in nuclear reactors... ..55 Annex B (informative) Examples of general confinement concepts for nuclear power reactors.......58 Annex C (informative) Examples of safety classification for nuclear power reactors... ..64 Annex D (informative) Examples of classification of working areas according to radiological contamination hazard . .66 Copyrght International OrganizaionStadardizaonghtsreserved ili out license from IH