United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 86-83: Underground Pathways into Protected Areas, Vital Areas, Material Access Areas, and Controlled Access Areas

                                                            SSINS No.:  6835
                                                            IN 86-83 

                                UNITED STATES
                           WASHINGTON, D.C. 20555

                             September 19, 1986

                                   VITAL AREAS, MATERIAL ACCESS AREAS, AND 
                                   CONTROLLED ACCESS AREAS 


All nuclear power reactor facilities holding an operating license or 
construction permit and fuel fabrication and processing facilities using or 
possessing formula quantities of special nuclear material. 


This notice is to advise licensees of the potential for undetected, 
unauthorized access to controlled areas on the site through unprotected, 
underground pathways. The existence of any unprotected underground pathway 
of the type described below may be considered a violation and may be 
reportable to the NRC in accordance with the appropriate sections of 10 CFR 
Part 73. 

It is expected that the recipients of this notice will review the 
information for applicability to their facilities and consider actions, if 
appropriate, to preclude similar problems from occurring at their 
facilities. However, suggestions contained in this information notice do not 
constitute NRC requirements; therefore, no specific action or written 
response is required at this time. 

Description of Circumstances: 

There have been a number of recent discoveries by licensees and NRC 
inspectors of underground pathways into protected areas (PAs), vital areas 
(VAs), material access areas (MAAs), and controlled access areas (CAAs). 
These pathways are normally some form of tunnel, pipe, or other design 
feature for which no protection had been installed or from which the 
protective features have been removed. (Protective features must provide a 
nonremovable physical obstacle to attempted entry to, or exit from, the 
tunnel.) Because these penetrations are often underground, traditional 
intrusion detection systems are ineffective for monitoring unauthorized 
attempts at entry, and the existence of such a pathway simultaneously 
defeats both the barrier and monitoring elements of access control. 



                                                       IN 86-83 
                                                       September 19, 1986 
                                                       Page 2 of 3 

The following examples were discovered at various sites during recent 

1.   Large piping used as part of the storm drain system led from outside 
     the PA to inside the PA where numerous unsecured manhole covers were 

2.   Personnel restraint bars which were required by design had not been 
     installed in a 20-inch drain line penetrating a vital area barrier. 

3.   Personnel restraint features installed in a heating, ventilating, and 
     air conditioning system had only bolted covers which failed to meet the
     standards for physical barriers, thereby reducing the overall level of 

4.   Two large storm drains penetrated the VA barrier and could be accessed 
     by as many as 30 unsecured manholes and other openings inside the PA. 
     One of the drain outfalls was covered by a grate that was secured by 
     four bolts into the concrete, but bolts had not been welded or peened 
     over and were accessible for easy removal by a hand wrench. The other 
     could be accessed through two manholes secured only with a metal strap 
     and brass shackled locks. 

5.   A drainage pipe extended from outside the PA into the PA. The manhole 
     cover intended to seal the opening inside the PA had originally been 
     welded closed, but traffic over the grate had broken the weld. 


Improperly secured underground pathways into PAs and VAs pose a potentially 
significant threat to site security because they allow unauthorized and 
undetected access. The seriousness of the threat is determined by the 
physical characteristics of the pathway, which include the type of entry as 
well as impediments to entry. 

Vital area barriers are expected to completely enclose vital equipment to 
prevent the introduction of objects and materials useful in sabotage as well
as to preclude unauthorized access by individuals. Therefore, any opening 
that reduces effectiveness of the barrier would be unacceptable. 

Any breach of a PA barrier that exceeds the industry standards of 96 square 
inches with at least one dimension greater than 6 inches (as referenced in 
NUREG-0908 and ANSI 3.3) is considered to be sufficient to allow the 
unauthorized entry of an individual. Therefore, openings into or out of 
tunnels that cross PA physical barriers may not exceed the 96-square-inch 
standard. Openings include the open ends of the tunnel, removable grates and 
manholes, and gaps in the grates and manholes. 


                                                       IN 86-83 
                                                       September 19, 1986 
                                                       Page 3 of 3 

However, the 96-square-inch standard applies only to two-dimensional 
openings and may not apply to large pipes and tunnels. Tunnels may be 
slightly larger than 96 square inches cross-section (11.04-inch diameter) 
and still preclude passage to a controlled area because its length and 
circuitous route may make it impossible for an intruder to move along the 
interior of the tunnel in such a small area. 

It is suggested that licensees review their physical barriers for suspected 
penetrations to assure that they conform to existing requirements. It is 
advisable that any variation from the 96-square-inch standard be documented 
and appended to the physical security plan (PSP). It is suggested that these
situations be evaluated and that a determination be made as to whether 
operational or physical impediments to entry should be installed. 

Continuous operational impediments to entry include such things as 
continuous flushing, high pressure areas, or other activity that would 
prevent a person from using the tunnel. Discontinuous or random operational 
impediments cannot adequately preclude unauthorized entry. 

Physical impediments to entry can include bars installed in the tunnel to 
reduce the size of the opening; grates or covers that are locked and 
alarmed, welded, or permanently installed in a way that precludes the entry 
of a person; bottlenecks in the tunnel; pipe bundles installed inside the 
tunnel; or other devices that form a barrier between the areas. Note that 
physical impediments must have penetration resistance equivalent to that 
specified in 10 CFR 73.2 for physical barriers. 

No written response to this information notice is required. If you need 
additional information about this matter, please contact the Regional 
Administrator of the appropriate NRC regional office or the technical 
contact listed below. 

                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contact:  Dick Rosano, IE 
                    (301) 492-4006 

Attachment:  List of Recently Issued IE Information Notices
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