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Information Notice No. 81-12: Guidance on Order Issued January 9, 1981 Regarding Automatic Control Rod Insertion on Low Control Air Pressure
SSINS No.: 6835 Accession No.: 8011040284 IN 81-12 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 March 31, 1981 Information Notice No. 81-12: GUIDANCE ON ORDER ISSUED JANUARY 9, 1981 REGARDING AUTOMATIC CONTROL ROD INSERTION ON LOW CONTROL AIR PRESSURE Description of Circumstances: The attached guidance has been provided to NRC inspectors to assist in the verification of BWR licensee action taken in implementation of the Order issued January 9, 1981 regarding automatic control rod insertion on low control air pressure. This guidance may also be of interest to BWR licensees, but does not in itself establish new or additional requirements. No written response to this information is required. If you need additional information regarding this matter, please contact the Director of the appropriate NRC Regional Office. Attachments: 1. Guidance on Order 2. Recently issued Information Notices . Attachment 1 IN 81-12 March 31, 1981 GUIDANCE ON ORDER The requirements of Section IV of the January 9, 1981 Order are quoted below with the appropriate guidance following each item. "(1) An automatic system shall be operable to initiate control rod insertion on low pressure in the control air header, which meets the following criteria:" "(a) The system shall automatically initiate control rod insertion at 10 psi or greater above scram outlet valve opening pressure." GUIDANCE In addition to the 10 psi requirement the base setpoint should be at least 50 psi. If the setpoint is not at least 50 psi, NRR should be informed to determine whether any further action might be necessary. "(b) The system shall not degrade existing safety systems (e.g., reactor protection system)." GUIDANCE If the system is interconnected with the reactor protection system, its components shall be qualified and its design shall be safety grade (i.e., conform with applicable IEEE standards). If the system is fully isolated or does not interconnect with the reactor protection system, its components shall be of a quality consistent with the requirements of item (d) below. "(c) The system shall allow for scram reset." GUIDANCE Scram reset is intended to accomplish only the return of control air and the subsequent closing of scram valves and opening of scram discharge instrumented volume (SDIV) vent and drain valves. "(d) The design shall consider the potential for inadvertent or unnecessary scrams." GUIDANCE This consideration would suggest the use of safety grade equipment for operational reliability reasons, but, as a minimum, control grade equipment may be used. "(e) Any required power supply should not be subject to any failure mode which could also initiate the degraded-air conditions, unless it can be demonstrated that an automatic scram will occur promptly because of the failure mode of the power supply." GUIDANCE This statement is self-explanatory. "(f) The system is not subject to the requirements of Appendices A and B of 10 CFR 50." . Attachment 1 IN 81-12 March 31, 1981 Page 2 of 2 GUIDANCE This criterion is applicable only for those automatic dump systems that do not interconnect with, or are fully isolated from the reactor protection system. For systems directly interacting with the reactor protection systems, the requirements of Appendices A and B of 10 CFR 50 are fully applicable. "(g) There shall be a documented independent design review of the system." GUIDANCE This statement is self-explanatory with the added provision that the conclusion reached will not include any unreviewed safety question. "(h) Before the system is declared operable, a documented preoperational test of the system will be successfully completed." GUIDANCE An integrated system test should be performed in every case. For those plants that remain operating and cannot perform a fully integrated test, demonstration of the portions of the system is a satisfactory test until an integrated test can be performed at the earliest outage for any purpose. "(i) The system shall be functionally tested at each unit shutdown, but not be tested more than once each 90 days." GUIDANCE This statement is self-explanatory. "(2) After April 9, 1981, the Automatic Dump System as described above shall be operable in all modes other than shutdown and refueling or the unit shall be placed in a cold shutdown condition within 72 hours unless system operability is restored." GUIDANCE This statement is self-explanatory.
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