United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 89-81: Inadequate Control of Temporary Modifications to Safety-Related Systems

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

                              December 6, 1989


Information Notice No. 89-81:  INADEQUATE CONTROL OF TEMPORARY 
                                   MODIFICATIONS TO SAFETY-RELATED SYSTEMS


Addressees:

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

Purpose:

This information notice is intended to alert addressees to potential 
problems resulting from inadequate control of temporary modifications to 
safety-related systems in operating nuclear plants.  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 do not constitute NRC 
requirements; therefore, no specific action or written response is required.

Description of Circumstances:

Several NRC design inspections of modifications to safety systems have 
revealed instances in which the licensee's control of temporary 
modifications to safety-related systems was inadequate.  Specifically, these 
inspections revealed that temporary modifications were not properly tracked, 
were not documented in a timely fashion, and were not given a timely 
technical review.  The following findings from four inspections illustrate 
these concerns.

Zion Nuclear Power Station, Unit 1 (50-295/88-03)

The inspection team reviewed the licensee's "Temporary Alteration Program" 
for the installation of temporary modifications to the safety systems.  This 
program had the following weaknesses.

1.   The program allowed immediate installation of a temporary modification 
     without a safety evaluation as required by 10 CFR 50.59.  In accordance 
     with the procedural guidelines, detailed technical analysis was not 
     required for a temporary modification that was installed for less than 
     30 days.  In addition, the program allowed the time frame for 
     performing the technical review to be extended to 60 days if the 
     temporary modifications were installed for use beyond 30 days.  Thus, 
     the modification could remain technically unreviewed for 60 days, and 
     if the modification 



8911300019 
.

                                                       IN 89-81
                                                       December 6, 1989
                                                       Page 2 of 4


     was cancelled within 30 days, it might never be analyzed.  Because an 
     assessment of the individual and synergistic effects of 30-day modifi-
     cations on the plant's safety systems was not performed, there was no 
     way of determining whether the safety of the plant had been compromised 
     by operating the systems with temporary modifications.  

2.   The program did not provide an effective system for tracking the 
     temporary modifications.  As a result, many temporary modifications 
     remained installed for a long time without being analyzed. 
     
3.   The program did not provide any directive for timely marking of the 
     control room copies of the controlled set of drawings to reflect a 
     modified configuration of the system after the temporary modification 
     had been installed.  Control room drawings that do not correctly 
     reflect the as-built plant configuration could impair the capability of 
     plant operators to troubleshoot problems and to operate the plant 
     safely. 

Sequoyah Nuclear Plant, Units 1 and 2 (50-327/86-27 and 50-328/86-27)

Temporary modifications at the Sequoyah plant were performed through the 
Temporary Alteration Control Form (TACF) program and associated 
administrative procedures.  The procedures addressed requirements for 
generation of follow-up documentation, such as design change requests 
(DCRs), which include a required detailed technical evaluation and also an 
evaluation to determine the possible existence of an unreviewed safety 
question.  The inspection team reviewed the TACF program and a sample of the 
temporary modifications installed through the TACF program.  This program 
had the following weaknesses.

1.   The TACF program did not require a DCR to be issued for a temporary 
     modification that was expected to be removed within 60 days of 
     installation.  Therefore, such modifications were not given the 
     detailed technical evalu-ation required by the DCR process.  Such a 
     modification could remain unreviewed for 60 days, and if the 
     modification was cancelled within 60 days, it might never be analyzed.  
     Because an assessment of the individual and synergistic effects of 
     60-day modifications on the plant's safety systems was not performed, 
     there was no way of determining whether the safety of the plant had 
     been compromised by operating the systems with temporary modifications.

2.   The TACF program was routinely used to make permanent changes in the 
     plant.  The decision to use this temporary modification program for 
     installation of permanent modifications was made at the discretion of 
     station personnel without adequate guidance.  Sometimes the decision 
     was based on merely whether the Engineering Department would be able to 
     provide a modification package in a timely fashion.  This approach 
     resulted in many installations of permanent modifications without 
     appropriate engineering evaluations. 

.

                                                       IN 89-81 
                                                       December 6, 1989 
                                                       Page 3 of 4 


3.   The TACF program did not have an effective system for tracking 
     temporary modifications.  This weakness resulted in installation of 
     many permanent changes in plant safety systems without the proper 
     safety evaluation and associated documentation.  The program lacked 
     instructions for updating controlled copies of the control room 
     drawings in a timely manner to reflect installed temporary 
     modifications.  These weaknesses resulted in many errors in the control 
     room drawings. 

Enrico Fermi Atomic Power Plant, Unit 2 (50-341/89-200)

The inspection team reviewed the licensee's "Temporary Modification Program" 
and a sample of the temporary modifications in detail.  One modification was 
installed during 1987 to silence a "high drywell temperature" alarm that was 
triggered by steam leaking from a valve in the drywell area.  The design 
temperature of the drywell was 135 F but the actual ambient temperature was 
about 200 F because of the steam leak.  Since the leak could not be fixed 
while at power, the temporary modification raised the alarm setpoint to 
silence the alarm.  The review of this modification revealed that the 
licensee's evaluation was inadequate.  The effects of higher drywell ambient 
temperatures on various design attributes, including environmental 
qualification of equipment in the vicinity, density compensation for the 
filled instrument sensing lines of the reactor instrumentation passing 
through the higher temperature area, and higher voltage drop in the cables 
and wires as a result of higher ambient temperatures, were not evaluated.  

Calvert Cliffs Nuclear Power Plant, Units 1 and 2 (50-317/89-200 and  
50-318/89-200)

The inspection team reviewed the licensee's "Temporary Modification Control" 
procedure and a sample of the temporary modifications in detail.  The team 
found that the licensee's temporary modification program failed to ensure 
the proper review of all modifications by the Plant Review Committee before 
their installation into the plant, and that the program was not under 
sufficient management oversight to minimize the number of temporary 
modifications installed.  The licensee's procedure permitted the shift 
supervisor to install any temporary modification for up to 24 hours without 
a technical review or a safety evaluation.  Although the licensee's 
technical specifications required that the Plant Review Committee review all 
proposed changes or modifications to plant systems or equipment affecting 
nuclear safety, the licensee's procedure allowed the installation of 
temporary modifications for up to 14 days with interim approval from two SRO 
licensed individuals, one of whom must be a shift supervisor.  The temporary 
modification tracking system was not being kept up to date.

Discussion:

It is important for licensees to evaluate the temporary modifications to 
safety-related systems before implementing these modifications.  The 
evaluation includes 

.

                                                       IN 89-81 
                                                       December 6, 1989 
                                                       Page 4 of 4 


verification that the modification will not have an adverse effect on the 
plant's systems, equipment, or safety.  Although licensees have generally 
met the NRC requirements in 10 CFR 50.59, some licensees have not exercised 
an adequate level of control for the activities associated with the 
temporary modifications to safety-related systems, as illustrated in the 
above-identified deficiencies. 

This information notice requires no specific action or written response.  If 
you have any questions about the information in this notice, please contact 
the technical contacts listed below or the appropriate NRR project manager. 




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


Technical Contacts:  E. V. Imbro, NRR
                     (301) 492-0954

                     S. V. Athavale, NRR
                     (301) 492-0974

                     J. R. Ball, NRR
                     (301) 492-0962


Attachment:  List of Recently Issued NRC Information Notices 
.
Page Last Reviewed/Updated Tuesday, November 12, 2013