United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 88-79: Misuse of Flashing Lights for High Radiation Area Controls

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                             WASHINGTON, D.C.  20555

                                 October 7, 1988

Information Notice No. 88-79:  MISUSE OF FLASHING LIGHTS FOR HIGH 
                                   RADIATION AREA CONTROLS


All holders of operating licenses or construction permits for nuclear power 


This information notice alerts addressees to problems involving the misuse of 
flashing lights for high radiation area (HRA) controls.  Five events involving
improper access control of high radiation areas are discussed.  Inappropriate 
use of such access controls could lead to potentially significant, inadvertent
radiation exposures.  It is expected that recipients will review the informa-
tion for applicability to their facilities and consider actions, as 
appropriate, to avoid similar problems.  However, suggestions contained in 
this information notice do not constitute NRC requirements; therefore, no 
specific action or written response is required.  


In several of the events discussed, it is apparent that plant workers and 
supervisors did not fully understand the technical specification (TS) 
requirements for HRA access control; therefore, a brief summary of the 
evolution of HRA controls for power plants could be useful.  

NRC regulations (10 CFR 20.202) define a high radiation area, in part, as 
having radiation levels that could cause whole-body doses in excess of 
100 millirem in 1 hour.  Specific HRA access control requirements (e.g., 
locking and positive control over entry) are contained in 10 CFR 20.203(c)(2).
These basic Part 20 HRA requirements were developed before the development of 
commercial power reactors.  

NRC recognized that requiring power reactor licensees to lock all areas that 
exceeded 100 mrem per hour was not appropriate because of the large number of 
such areas, as well as the general state of sophistication of the typical 
radiation protection program (which includes RWP controls, surveillance pro-
grams, comprehensive worker training, and professional technical HP staff, 
among others).  Therefore, beginning in the mid-1970s, TS amendments were 
issued to some power reactor licensees allowing them to lock only areas 


                                                            IN 88-79
                                                            October 7, 1988
                                                            Page 2 of 3

with dose rates of 1000 mrem/hr or more, providing that additional specified 
controls were implemented.  Subsequent to these amendments, certain TS were 
further amended to recognize that there were particular HRAs that, because of 
their configuration, it was not reasonable to enclose and lock.  This change 
allowed the use of a flashing light in place of a locked enclosure but was 
only permitted for unusual cases if no enclosure could reasonably be 
constructed around the component or area.  

Description of Circumstances:

In recent months, NRC inspections have identified at least five incidents 
where licensees have misused the TS requirement that allows the use of 
flashing lights in lieu of a locked enclosure around a high radiation area as 
acceptable practice for any high radiation area.  The examples listed in 
Attachment 1 describe situations in which the level of personnel protection 
was unnecessarily reduced because of misuse of Standard Technical 
Specification (STS) 6.12.  Corrective actions taken included (1) locking the 
door to an HRA enclosure that already existed, (2) installing an enclosure 
around the HRA, or (3) shielding a localized source such that dose rates were 
reduced to less than 1000 mrem/hr.  Although doses in excess of NRC limits did
not result from any of these events involving misuse of HRA access controls, 
all situations had the potential of resulting in a significant radiation dose.


Presently, STS 6.12 addresses an alternative control method for locked 
entrances for HRAs in accordance with 10 CFR Part 20.  In part, STS 6.12 
states that "For individual areas accessible to personnel with radiation 
levels such that a major portion of the body could receive in one hour a dose 
in excess of 1000 mrem [measurement made at 18" from the source of 
radioactivity] that are located within large areas such as PWR containment, 
where no enclosure exists for purpose of locking, and no enclosure can be 
reasonably (emphasis added) constructed around the individual areas, then 
that area shall be barricaded, conspicuously posted, and a flashing light 
shall be activated as a warning device...."  As described in Attachment 1, 
several licensees have misused flashing lights and barricades to control 
access to HRAs having radiation levels greater than 1000 mrem/hr in situations
in which more positive access control was possible by constructing a lockable 
enclosure or locking the enclosure that already existed.  

All power reactor licensees having the above-described provision in their 
technical specifications are permitted to use barricades, posting, and 
flashing lights to control access to high radiation areas wherein dose rates 
of 1000 mrem/hr or more exist and that cannot be reasonably enclosed.  
Conversely, if it is reasonable to construct a locked enclosure, then access 
control with barricades, posting, and flashing lights is not permitted.  


                                                            IN 88-79
                                                            October 7, 1988
                                                            Page 3 of 3

No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact one of the 
technical contacts listed below or the Regional Administrator of the 
appropriate regional office.  

                              Charles E. Rossi, Director
                              Division of Operational Events Assessment
                              Office of Nuclear Reactor Regulation

Technical Contacts:  Thomas H. Essig, NRR
                     (301) 492-3146

                     James E. Wigginton, NRR
                     (301) 492-1136

1.  Examples of Misuses of STS 6.12
2.  List of Recently Issued NRC Information Notices

                                                            Attachment 1
                                                            IN 88-79
                                                            October 7, 1988
                                                            Page 1 of 2

                         Examples of Misuses of STS 6.12

x    Washington Nuclear Project (WNP)-2 (Inspection Report No. 50-397/88-22)

     During an inspection conducted in June 1988, NRC inspectors noted an area
     containing sources having radiation levels up to 1500 mrem/hr at 
     18 inches that was equipped with a lockable door.  The door was unlocked;
     access control was handled through use of a flashing light and barricade. 
     A health physics (HP) supervisor employed by the licensee stated that he 
     believed that STS 6.12 allowed warning lights to be used at any HRA 
     location in lieu of locking the area or constructing enclosures.  Discus-
     sions with equipment operators revealed that four out of the five opera-
     tors interviewed did not know the purpose of the flashing lights; the 
     fifth individual knew their purpose but felt training provided him on 
     this subject was deficient.  

x    Point Beach (Inspection Report Nos. 50-266/88013 (DRSS) and 50-301/88012 

     While performing radiation surveys in April 1988 on the 66-foot level of 
     the Unit 1 Containment Building during a fuel element transfer, NRC 
     inspectors noted that a procedurally required HRA flashing red light was 
     installed but not in use.  The HRA existed because of radiation emanating
     from the fuel element transfer canal through a 2-inch gap between the 
     containment wall and the floor.  Dose rates up to 6000 mrem/hr existed in
     this area during fuel transfer.  Just before the inspection, a 
     night-shift refueling supervisor had the flashing red lights turned off 
     by the HP organization after he found them to be a distraction.  

x    Wolf Creek (Inspection Report No. 50-482/88-09)

     In March 1988, an NRC inspector noted that a Durateck portable 
     demineralizer skid was posted as an HRA with radiation levels in excess 
     of 1000 mrem/hr.  A rope barrier and a flashing light were used to 
     control access to the immediate area around the skid.  The maximum 
     radiation level at 18 inches from the source was 1300 mrem/hr.  Although 
     it was feasible to construct an enclosure around this skid, the licensee 
     believed that the area containing the demineralizer skid constituted a 
     "large area" as used in STS 6.12.  

x    Vogtle (Inspection Report No. 50-424/88-13)

     During February 1988, an NRC inspector noted that access to an HRA enclo-
     sure containing a spent resin line was through a lockable door and that 
     the key had broken in the lock.  Access to the area was controlled as an 
     HRA by a flashing light and a barricade.  Dose rates up to 3500 mrem/hr 
     (18 inches from the source) existed inside the HRA.  As was the case with
     WNP-2, the licensee believed that STS 6.12 permitted the use of flashing 
     lights in lieu of locking the HRA access door.  


                                                            Attachment 1
                                                            IN 88-79
                                                            October 7, 1988
                                                            Page 2 of 2

x    Farley (Inspection Report Nos. 50-348/88-02 & 50-364/88-02)

     One room and a portion of another were posted as an HRA having radiation 
     fields greater than 1 rem/hr.  The entrance to this area was not locked, 
     although it was barricaded by three yellow and magenta ropes, a flashing 
     red light, and high radiation area/exclusion area warning signs.  Radia-
     tion exposure rates in the inner room ranged up to 240 R/hr at contact 
     and approximately 150 R/hr at 18 inches from the surface of a tank.  As a
     result of miscommunications, two workers entered the area on December 28,
     1987, to perform decontamination activities without either the 
     appropriate monitoring equipment or being accompanied by an 
     HP technician.  One worker entered the area and worked approximately 
     5 feet from the spent fuel pool demineralizer.  After approximately 
     5 minutes, this worker observed that his low-range dosimeter was 
     offscale; he immediately exited the room and reported to an HP 

     Although no exposures in excess of NRC limits resulted from these activi-
     ties (maximum dose was 455 mrem), the situation represented a significant
     potential for an overexposure because of the lack of communication and 
     the lack of adequate access controls.  The licensee in this case also 
     believed that STS 6.12 permitted the use of flashing lights and rope 
     barriers as an access control to an HRA having radiation levels greater 
     than 1 rem/hr in lieu of locking the door to the area.  

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