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HomeNRC LibraryDocument CollectionsGeneric CommunicationsInformation Notices1993

# Information Notice No. 93-94: Unauthorized Forced Entry into the Protected Area at Three Mile Island Unit 1 on February 7, 1993

```
                                 UNITED STATES
                         NUCLEAR REGULATORY COMMISSION
                     OFFICE OF NUCLEAR REACTOR REGULATION
                            WASHINGTON, D.C. 20555

                               December 9, 1993

NRC INFORMATION NOTICE 93-94:  UNAUTHORIZED FORCED ENTRY INTO THE PROTECTED
                               AREA AT THREE MILE ISLAND UNIT 1 ON
                               FEBRUARY 7, 1993

Addressees

All holders of operating licenses or construction permits for nuclear power
reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees of potential safety/safeguards issues raised as a
result of an unauthorized forced entry into a protected area at Three Mile
Island (TMI) Nuclear Generating Station.  It is expected that recipients will
review the information for applicability to their facilities and consider
actions, as appropriate, to avoid similar problems.  However, suggestions
contained in this information notice are not NRC requirements; therefore, no
specific action or written response is required.

Description of Circumstances

On February 7, 1993, TMI Unit 1 was operating at full power.  At 6:53 a.m. an
intruder drove a station wagon into the TMI site entrance and continued past
the north gate guard house of the owner-controlled area.  The intruder was
traveling in the outbound traffic lane at an estimated 54-64 km per hour 
[35-40 miles per hour].  After observing that the intruder had failed to stop
at a posted stop sign, the site protection officers at the north gate notified
other onsite protection officers, thus prompting security personnel to
respond.  The vehicle then passed through a second stop sign and continued
toward the processing center building for the protected area, which it
skirted, heading toward the protected area gate.  

The vehicle breached the gate, thus activating the protected area alarm system
and prompting security personnel to assess the situation on closed circuit
television.  The vehicle proceeded approximately 57 m [189 feet] and crashed
through the Unit 1 turbine building aluminum rollup door.  The vehicle caused
damage to a secondary system condensate resin liner, an auxiliary steam line,
and auxiliary support equipment. 

The plant operators in the control room were notified of the event by a call
from the outgoing operations shift foreman who had witnessed the event and a
site protection officer who had been informed of the event by the north gate 

9312030104.

                                                            IN 93-94
                                                            December 9, 1993
                                                            Page 2 of 5

site protection officers.  Control room personnel responded by implementing
emergency response procedures, including locking control room fire doors,
classifying the event as a site area emergency, performing required 
notifications, and maintaining and monitoring the plant at full power. 

The security staff responded by posting site protection officers to intervene
at predesignated vital areas, confirming vital area integrity, and with the
aid of offsite responders, assessing the threat and searching for the
intruder.  The U.S. Army explosives ordnance disposal unit responded and
surveyed the vehicle for suspicious objects, conducted a search for explosive
devices, and removed the vehicle from the turbine building. 

During the search-and-clear operations, TMI security personnel and offsite
response personnel found and apprehended the unarmed intruder at the bottom of
the turbine building in a small space under piping in the condenser area.    

Following the operations shift supervisor declaring a site area emergency, the
site emergency response program was implemented and the Commonwealth of
Pennsylvania response organizations and the NRC were notified of the event. 
Due to the potential security threat at the time, the licensee chose not to
fully activate its emergency response organizations.  Personnel safety
considerations prompted a decision not to staff the inplant technical support
center or operations support center while the intruder was at large.  

After visually inspecting plant equipment, verifying that operating plant
parameters were within the technical specification license criteria, and
confirming that the safety systems were available, the licensee ended the site
area emergency at 4:25 p.m.

On February 8, 1993, the NRC Executive Director for Operations directed that
an NRC incident investigation team be established to investigate the event. 
The team consisted of NRC personnel with a broad knowledge of physical plant
security, safeguards, emergency planning, plant systems and operations, and
criminal investigation, and an industry representative.

Discussion

The incident investigation team findings and conclusions are contained in both
the public and safeguards versions of NUREG-1485, "Unauthorized Forced Entry
Into the Protected Area at Three Mile Island Unit 1 on February 7, 1993,"
issued in April 1993.  Some of the issues raised by the team with regard to
the event and subsequent declaration of a site area emergency are relevant to
operations at a power reactor site.  These issues are summarized as follows:

(1)   Protected Area Barriers and Assessment System

      The performance objectives of Title 10 to the Code of Federal
      Regulations (10 CFR) Part 73 do not specifically address preventing a
      vehicle from forced entry through the protected area barrier and that
.

                                                            IN 93-94
                                                            December 9, 1993
                                                            Page 3 of 5

      there is no NRC guidance specific to performance standards for a
      security response to such an intrusion.  Notwithstanding this, the TMI
      Unit 1 assessment system was not effective in observing the
      intruder/vehicle penetrating the protected area barrier.  Although the
      protected area detection system functioned (alarmed) as designed, the
      use of a land vehicle reduced the available time that security personnel
      had to respond and significantly affected their strategy toward
      protecting vital areas. 

(2)   Interface Between Operations, Emergency Response, and Physical Security       Response Activities

      Shortly after the protected area barrier was breached, the operator at
      the central alarm station implemented a procedure to limit access to
      vital areas.  Implementation of the procedure reduced the number of key
      cards that would open vital area doors and resulted in only one member
      of the onshift operations crew having a valid key card to enter the
      vital areas.

      The TMI emergency operating procedure for responding to a penetration of
      the protected area specified that the control room fire doors (which
      were not vital area doors) be locked.  A basis for this procedural
      requirement was not established.  Locking the fire doors isolated the
      control room from the staff and equipment needed to implement the
      emergency response plan and introduced potential problems for plant
      operations.

      The decision to maintain stable, steady-state reactor operations at full
      power during the security incident was in accordance with an established
      emergency operating procedure and found to be appropriate by the
      incident investigating team.  However, the procedure did not contain
      qualifying guidance to the operators.  The incident investigating team
      noted that maintaining stable, steady-state operations at full power may
      not be appropriate for all security event conditions covered by the
      procedure.

(3)   Effect of security on Licensee Emergency Response and on Emergency Plan
      Implementation

      The shift operations supervisor was initially distracted from making the
      event classification and emergency declaration partly because of
      personnel safety concerns.  His first priority was to lock the fire
      doors to the control room.  Personnel safety considerations also
      prompted a decision not to staff the normal designated in-plant
      technical support center or the operations support center which are
      located in the control tower.  Instead, an ad hoc decision was made to
      direct the technical support center and operations support center
      personnel to the training center.  In addition, the Emergency Director
      responded to the central alarm station, which had the effect of
      relocating the emergency control center from the control room area to
      the service building.  This relocation created confusion and complicated
      implementation of the emergency response plan.  The licensee focused on
.

                                                            IN 93-94
                                                            December 9, 1993
                                                            Page 4 of 5 

      re-establishing the security of the facility and eliminating the
      intruder, thus obscuring the broader emergency response measures 
      required for potential radiological sabotage.  

(4)   Process for Implementing 10 CFR 50.54(x) and (y) Provisions

      During the event, the licensee suspended normal security entry
      processing into the protected area to allow offsite personnel to have
      free access to the vehicle and to conduct associated investigations. 
      Routine security checks and records also were suspended.  Although the
      suspension of security requirements is addressed in 10 CFR 50.54(x) and
      (y), compensatory alternatives were not considered in their application
      during this event.  Additionally, the licensee did not report to the NRC
      Operations Center that it had suspended certain security measures in
      accordance with the provision of 10 CFR 50.54(x).

(5)   Communications Systems 

      During the event, several difficulties arose that adversely affected
      communications with offsite organizations and licensee emergency
      response staff.  Only certain telephones were specified by procedures to
      be used for emergency notifications and callbacks, and these telephones
      were not accessible because the control room fire doors were locked. 
      The individuals making notifications and callbacks were not trained in
      the procedures they were to follow.  Although the central alarm station
      was used as the emergency control center, the central alarm station
      communications capability was not designed to support both emergency
      preparedness and security functions.  Also, the licensee telephone
      system had an off-hours restriction that did not permit outgoing calls
      from certain telephones.  This restriction was not completely lifted
      until 7.5 hours after the intruder penetrated the protected area.  In
      addition, the NRC did not have access to information in the emergency
      response data system because of a telephone line failure at TMI.

The above items illustrate a broad spectrum of activities that were not
anticipated or covered by procedures.  While it cannot be expected that every 
variable of a security event can be anticipated in advance, there may be some
lessons learned from the event that can be applied generally.  On the basis of
the NRC incident investigation team findings with respect to this event, the
NRC staff is considering the need for additional regulatory actions.

.

                                                            IN 93-94
                                                            December 9, 1993
                                                            Page 5 of 5

This information notice requires no specific action or written response.  If
you have any questions about the information in this notice, please contact
one of the technical contacts listed below or the appropriate Office of
Nuclear Reactor Regulation (NRR) project manager.

                                 /S/'D BY BKGRIMES

                                 Brian K. Grimes, Director
                                 Division of Operating Reactor Support
                                 Office of Nuclear Reactor Regulation 

Technical contacts:  Michael S. Warren, NRR
                     (301) 504-3211

                     Donald M. Carlson, NRR
                     (301) 504-3212

Attachment:  
List of Recently Issued NRC Information Notices
.
```

*Page Last Reviewed/Updated Tuesday, November 12, 2013*

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