IE Circular No. 78-08, Environmental Qualification of Safety-Related Electrical Equipment at Nuclear Power Plants
CR78008
UNITED STATES
NUCLEAR REGULATORY COMMISSION
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
SUBJECT: IE CIRCULAR 78-08, ENVIRONMENTAL QUALIFICATION OF
SAFETY-RELATED ELECTRICAL EQUIPMENT AT NUCLEAR
POWER PLANTS
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
letter.
Norman C. Moseley, Director
Division of Reactor Operations
Inspection
Office of Inspection and Enforcement
Enclosures:
1. IE Circular 78-08
2. Draft Transmittal Letter
CONTACT: V. D. Thomas, IE
49-28180
.
(Transmittal letter for Circular 78-03 to each holder of an NRC Reactor
Operating License and Construction Permit.)
IE Circular 78-08
Addressee:
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.
Signature
(Regional Director)
Enclosure:
1. IE Circular 78-08
2. List of IE Circulars
Issued in 1978
.
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
May 31, 1978
IE Circular 78-08
ENVIRONMENTAL QUALIFICATION OF SAFETY -RELATED ELECTRICAL EQUIPMENT AT
NUCLEAR POWER PLANTS
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
equipment.
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
conditions.2/
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
progress.
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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REFERENCES
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.
50-255.
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.
50-316.
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.
.
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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.
50-316.
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021