IE Circular No. 78-08, Environmental Qualification of Safety-Related Electrical Equipment at Nuclear Power Plants


                              UNITED STATES 
                         WASHINGTON, D. C. 20555 

                               MAY 31, 1978 

MEMORANDUM FOR:     B. H. Grier, Director, Region I 
                    J. P. O'Reilly, Director, Region II 
                    J. G. Keppler, Director, Region III 
                    K. V. Seyfrit, Director, Region IV 
                    R. H. Engelken, Director, Region V 

FROM:               Norman C. Moseley, Director, ROI, IE 


The subject document is transmitted for issuance on May 31, 1978. The 
Circular should be issued to all holders of Reactor Operating Licenses and 
Construction Permits. Also enclosed is a draft copy of the transmittal 

                                        Norman C. Moseley, Director 
                                        Division of Reactor Operations 
                                        Office of Inspection and Enforcement

1.  IE Circular 78-08 
2.  Draft Transmittal Letter 

CONTACT:  V. D. Thomas, IE 

(Transmittal letter for Circular 78-03 to each holder of an NRC Reactor 
Operating License and Construction Permit.) 

                                                        IE Circular 78-08  

The enclosed Circular 78-08 is forwarded to you for information. If there 
are any questions related to your understanding of the suggested actions, 
please contact this office. 

                                        (Regional Director) 

1.  IE Circular 78-08 
2.  List of IE Circulars 
      Issued in 1978  

                             UNITED STATES 
                         WASHINGTON, D. C. 20555 

                              May 31, 1978  

                                                        IE Circular 78-08  


The NRC staff initiated a series of actions to confirm the environmental 
qualification of electrical equipment required to perform a safety function 
under postulated accident conditions. These actions are summarized in the 
Commission's April 13, 1978 Order in response to a petition from the Union 
of Concerned Scientists. Information obtained from recent licensee equipment
tests and evaluations have indicated potential problems in qualification of 
installed equipment. As a result, the NRC expanded these actions to include 
an environmental review of safety-related electrical equipment at selected 
older plants.1/ This review did not identify generic qualification 
deficiencies. However, as a result of IE Bulletins and the aforementioned 
testing to confirm qualification, specific deficiencies were identified. 
Poor installation practices, inadequate consideration of subcomponents and 
omission of certain environmental parameters in the design are examples of 
such deficiencies. In addition, the documentation of qualification was found
to be inadequate in many cases and the initial response to some licensees 
indicated a lack of detailed knowledge of the quality of installed 

The purpose of this Circular is to bring to your attention such deficiencies
and to highlight the important lessons learned. In its April 13, 1978 Order,
the Commission indicated that 

     "In order to fulfill its regulatory obligations, NRC is dependent upon 
     all of its licensees for accurate and timely information. Since 
     licensees are directly in control of plant design, construction, 
     operation and maintenance, they are the first line of defense to ensure
     the safety of the public. NRC's role is one primarily of review and 
     audit of licensee activities, recognizing that limited resources 
     preclude 100 percent inspection. 

     Furthermore, the Commission notes that some of the licensee's initial 
     responses indicate a lack on their part of detailed knowledge of the 
     quality of installed plant equipment. Licensees must have this detailed
     understanding of their own plants in order to meet their obligations 
     for public,safety by ensuring a 

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IE Circular 78-08                                       May 31, 1978       

     sound basis for making assessments of plant safety. The NRC establishes
     general safety criteria, sets specific requirements for many aspects of
     reactor design and operation, and ensures compliance with these 
     criteria and requirements by independent audit. While, in the 
     Commission's view, these activities play a vital role in ensuring safe 
     plant operation, they are not a substitute for licensee safety reviews. 
     The licensees must be knowledgeable and vigilant and must take more 
     initiative in ferreting out details of potential plant weaknesses." 
As part of this obligation, you should examine installed safety-related 
electrical equipment, and ensure appropriate documentation of its 
qualification to function under postulated accident conditions. Specific 
guidance on the subject of environmental qualification can be found in IEEE 
323-1971 and 1974, as augmented by Regulatory Guide 1.89. 

Examples of specific deficiencies identified in information provided by 
licensees are as follows: 

1.   Connectors: Responses to IE Bulletins 77-05 and 77-05A revealed in 
     certain instances a lack of qualification data for environmental 
     parameters and inadequate design of connectors for postulated accident 

2.   Penetrations: A failed penetration prompted issuance of IE Bulletin 
     77-06. Responses to this bulletin showed adequate documentation for the
     qualification of the penetration assembly was not readily available in 
     some cases.2/ In one instance, the electrical connections of the 
     penetrations were not qualified ih conjunction with the penetration 
     assembly,3/ which demonstrates a lack of consideration for 
     qualification of interfacing components. 

3.   Terminal blocks: Because of unprotected terminal blocks in penetration 
     areas inside containment of Haddam Neck, Bulletin 78-02 was issued. 
     These unprotected blocks were replaced with blocks designed to function
     in the LOCA and main steam line break environments.4/ Responses to the 
     Bulletin revealed two other facilities, Yankee Rowe and Ginna, with 
     such unprotected blocks.5/,6/ Other terminal blocks were found to be 
     inadequately qualified due to poor design or installation practices, 
     even though they were in enclosures.7/,8/,9/ and 10/ 
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IE Circular 78-08                                       May 31, 1978       

4.   Limit switches: While examining the documentation for the qualification
     of all safety-related equipment installed inside containment, a vendor 
     identified limit switches mounted on otherwise qualified valves at 
     certain facilities. Preliminary review by the staff of responses to IE 
     Bulletin 78-04 indicates such switches are installed in similar 
     applications at other facilities. Corrective action is presently in 

5.   Cable splices: Electrical cable splices associated with electrical 
     penetration assemblies were determined to be unqualified by licensees 
     during their search for qualification documentation.11/ 

6.   Other potential problems for specific components currently under staff 
     review include: 

     -radiation and temperature effects on electrical cables10/ 

     -adequacy of qualification testing of components by separate effects 
      versus sequential testing of environmental parameter10/ 

     -temperature limitations on nylon components of solenoid valves12/ 

     -qualification of electrical transmitters 13/, 14/ 

The review of these issues may result in the need for other followup or 
corrective actions. 

No written response to this Circular itself is required. Each licensee 
should determine the applicability of the qualification items identified 
above for its facility. Appropriate corrective action should be taken for 
any problem identified by the licensee as a result of its review. NRC 
inspectors will review these matters with licensees in future inspections. 
If further information is required, contact the Director of the appropriate 
Regional Office.  

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1.   "Short Term Safety Assessment on the Environmental Qualifications of 
     Safety-Related Electrical Equipment of SEP Operating Reactors," May 
     1978, enclosure to staff memorandum to Commission, dated May 12, 1978 
     and issued as NUREG Report 0458. 

2.   "NRC Staff Report on Union of Concerned Scientists' Petition for 
     Emergency and Remedial Action," December 15, 1977, enclosure to staff 
     memorandum to Commission, dated December 15, 1977. 

3.   Letter from Consumers Power Company to NRC dated April 6, 1978, 
     including, "Summary of Qualifications of Electrical Penetration 
     Assembly Connectors for the Palisades Plant," Docket No. 50-255. 

4.   NRC Summary of January 29, 1978 meeting on "Environmental Qualification
     of Terminal Blocks and Replacement of Terminal Blocks, Haddam Neck 
     Plant," Docket No. 50-213, dated January 30, 1978. 

5.   NRC Summary of February 1, 1978 meeting, Yankee Rowe Nuclear Power 
     Station (terminal blocks), Docket No. 50-29, dated February 3, 1978. 

6.   NRC Summary of February 1, 1978 meeting on "Environmental Qualifica-
     tion of Terminal Blocks and Replacement of Terminal Blocks," R. E. 
     Ginna Nuclear Plant, Docket No. 50-244 dated February 2, 1978. 

7.   Letter from Connecticut Yankee Atomic Power Company to NRC, dated March
     29, 1978, including "Haddam Neck Plant Summary of Environmental 
     Qualification Test Program, Terminal Block/Box Combinations," Docket 
     No. 50-213. 

8.   Letter from Consumers Power Company to NRC, dated April 12, 1978, 
     including information on terminal blocks at Palisades, Docket No. 

9.   Letter from Indiana & Michigan Power Company to NRC, dated March 22, 
     1978 regarding terminal blocks at D. C. Cook Unit No. 2, Docket No. 

10.  Letter from Indiana & Michigan Power Company to NRC, dated April 21, 
     1978, regarding terminations at D. C. Cook Unit Nos. 1 and 2, Docket 
     Nos. 50-315 and 50-316. 

11.  Staff memorandum, "Status of Monticello Electrical Splice Upgrade," 
     dated May 10, 1978, Docket No. 50-263. 

12.  Letter from Consumers Power Company to NRC, "'Environmental Qualifica-
     tion for Big Rock Point," dated February 24, 1978, Docket No. 50-155. 


13.  Letter from Consumers Power Company to NRC, "Environmental Qualifica-
     tion for Palisades," dated February 24, 1978, Docket No. 50-255. 

14.  Letter from Westinghouse to E. G. Case, dated April 26, 1978, regarding
     environmental qualification status for D. C. Cook Unit 2, Docket No. 

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