United States Nuclear Regulatory Commission - Protecting People and the Environment

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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