ML17037B512

Letter Regarding IE Bulletin No. 77-05 on Electrical Connector Assemblies

ML17037B512
Person / Time
Site:	Nine Mile Point
Issue date:	11/18/1977
From:	Case E Office of Nuclear Reactor Regulation
To:	Rhode G Niagara Mohawk Power Corp
References
BL-77-005
Download: ML17037B512 (14)

Text

Docket Noi 50-220 Niagara Hohawlc Power Corporation ATTN:

Fh'w Gerald Ywi Rhode Vice President Engineering

'300 Erie Boulevard Vest

Syracuse, New York l3202 Gentlemen:

On or, about November 8, 1977, you should have received XE Bulletin No.

77-'05 on Electrical Cce~neetor Assemblies from the Regional Office of the HRC Office of Inspection and Enforcement, and a supplement to this Bull~tin on or about November 15, 1977, (copies enclosed).

This Bulletin requests that, within $0 days, you provide information on whether your Nine ffile Point Unit; 1 facility utilizes electrical connector assemblies within containment that could be subJect, to an accident environment and are required to be operable during an accident; and, ifit does, to provide documentation of the environmental qualification testing performed for these connectors.

h Pue to the, safety significance of this matter, the staff also conducted a telephone survey of all operating plants to obtain preliminary inform-tion on which facilities utilize such connectors and the adequacy of qualification testing of any, such connectors.

As you know, this survey determined that such eonneetors are used in your Nine &le Point Unit 1 facility. Further, as a result, of meetings held with your representa-tives during the weel< of November 10, 1977, we determined on a preliminary

basis, that the el'ectrical connectors used in your facility are of the general type that failed in tests conducted at the Sandia Laboratories.

At these meetings, you were unable to provide the environmental qualifi-cation documentation'ou advised us that, your plant uses connectors manufactured by the Di G. O'rien Company and that qualification tests DPPICE~

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Niagara Hohawk Power Corporation on these connectors have been conducted.

From infornat$on we received during our survey about the test performance of other D, G. O'rien connectors at other facilities, satisfactory qualification of these connectors at your facility is likely.

Because of the safety importance of these connectors, you are hereby requested, pursuant to 10 CFR 50,54(f) of the Coomdasion's regulations, to deliver to the Office of Nuclear Reactor Regulation, Nuclear Regulatory Cotmission, Vashington, Dd C.

20555, not later than November 28, 1977, information which establishes the required environmental qualification of the connectors used in your facility.

This information should include all that requested by IE Bulletin No> 77<<05 and Supplement 77-05A thereto, including in particular consideration of accident; radiation and steam conditions, Xf you are not able to provide complete documentation of the required qualification'testing of all applicable connectors, you should, as indicated in the Bulletin, submit, plans and programs for qualifying existing equipment or plans for replacing unqualified connectors with qualified equipment.

ln this case, you must, also include with your response a Justification that continued operation of the facility, for whatever period it will take to environmentally qualify the connectors in accordance with NRC regulations, would not, create undue risk to the health and safety of the publics Please advise us if you have any questions relative to this matter.

Sincerely, Original signed by F

'f Edson G. Case, Acting Director Office of Nuclear Reactor Regulation DISTRIBUTION:

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0 UNITEDSTATES NUCLEAR REGULATORY COMMISSION WASHINGTON D. C. 20555 November 18, l977 Docket Noi 50-220 Magara Mohawk Power Corporation ATTN:

Mr. Gerald.K+

Rhode Vice President - Engineering 300 Erie Boulevard Nest

Syracuse, New York 13202 Gentlemen:

-On or abou+

November 8, 1977, you should have rec ived IE Bulletin No, 77-05 on Elec+rical Connector Assemblies from the Regional Office of the NRC Office of Inspection and Fnforcem nt and a supplement to +his Bulletin on or about November 15, 1977, (copies enclos'ed).

This Bulletin requests tha+, within 30 days, you pr ovide information on whether your Nine Mile Point Unit 1 facility utilizes electrical connector assemblies wi+hin cont~inment that could be subject. to an acciden'nvironm nt and are required +o be operable during an acciden';

and, if i+ does, to provide docuII.ntation of the environmental qualification testing performed for these connectors.

Due to the safe+y significance of this matter, the staff also conducted a telephone survey of all operating plants to obtain preliminary informa-tion on which facili.ies utilize such connectors and the adequacy of qualification tes+ing of any such connectors.

As you know, this survey

~ determined that such cc~nectors a'e used in your Nine Mile Point Unit-1 facility. Further, as a result of meetings held with your representa-tives during the week of November 14, 1977, we determined on a preliminary basis, that the electrical connectors used in your.facili+y are of the general type that failed in tests conducted at the Sandia Laboratories, At these mee+ings, you were unable to provide the erivironmental qualifi-ca+ion docurentation.

You advised us that your plant uses connectors

. manufactured by the D

G, O'rien Company and that qualificgtion test

Niagara Mohawk Power Corporation Noyemb'ep 18, 1977 on these connectors have been conducted, From information we received during our survey about, the test performance of other D, G, O'rien connectors at o+her facilities, satisfactory qualification of these connec+ors a+ your facility is likely.

Because of the safety importance of these connectors, you are hereby requested, pursuant to'10 CFR 50;54{i) of the Coded.ssion's regulations, to deliver to the Office of Nuclear Reactor Regulation, Nuclear Regula+ory Commission, Mashington, D. C.

20555, not later than November 28, 1977, information which establishes the required environmental qualification of the conneotor s used in your facility+

This informa+ion should include all that requested by IE Bulletin No. 77-05 and Supplement 77-05A theret,o, including in particular consideration of accident radiation and steam eondi+ions.

A.

Xf you are no" able to provide complete documentation of the required qualification.testing. of all applicable connectors, you should, as indicated in the Bulle+in, submit plans 'and programs for qualifying existing equipment or plans for replacing unqualified connect,ors with qualified equipmen+,

In this case, you must, also include wi+h your response a justification that continued operation of the facility, for wha+ever period it, will take to environmentally qualify the connectors in accordance with NRC regulations, would not create undue risk to the health and safety of the.public>

Please advise us if you have any questions relative to this matter.

~

Edson G, Case, Acting Direct,or Office of Nuclear Reactor Regulation

Niagara Mohawk Power Corporation CC Eugene B. Thomas, Jr., Esquire

LeBoeuf, Lamb, Leiby 8 MacRae l757 N Street, N.

W.

Washington, D. C.

20036 Anthony Z. Roisman, Esquire

Sheldon, Harmon and Roisman 1025 15th Street, N.

W.

5th Floor Washington, D.

C.

20005 Oswego County Office Building 46 E. Bridge Street Os..ego, New York 13126

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. TRIP REPORT by M. R. Rutherford IE Bulletin-77-05 November 8, 1977 ELECTRICAL CONNECTOR ASSEMBLIES On September 1, 1977 a meeting was held in Alburquerque, New Mexico to

)pvestigate the electrical connector assembly malfunctions or failures that occurred during tests under LOCA conditions performed by Sandia Laboratories.

The following is a description of the equipment, test scopo and results of these tests.

r Equipment The test assemblies of particular.interest consisted of three types of connectors:

Bendix, ITT Cannon, and Gulton ipstalled on two types of cables; Anaconda and ITT. Surprenant...

1.

Bendix Connector:

A 3 conductor/No.

12 AWG with crimp pin conductors, anodized aluminum shell, silicone, ribber insert, rigid back plane potting, pliable over-potting.

2.

ITT Cannon Connector; A 3 conductor/No.

12 Ah'G with crimp pin conductors, anodized aluminum shell, silicone rubber insert, anodized aluminum back shell, rubber packing boot, mechanical retaining clamp.

3.

Gulton 'Connector:

A 3 conductor/No.

12 AMG with crimp pin conductor, stainless steel shell, hard fiber insert, pin back sealed with RTV 112, stainless shell, back plane poured with Sylgard potting, mechanical

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clamp termination.

4.

Anaconda Cable:

A 3 conductor/No.

12 AllG, tinne'd copper conductor, 30 mil ethylene propylene rubber insulation 15 mil Hypalon jacket, cable asbestos

tape, 60 mil Hypalon jacket, rated 600 yolts, cable diameter 0.55".

S.

ITT Surprenant Cable:

p 3 conductor/No.

12 Al<G, tinned copper conductor, 30 mil Exane II insulation, silicone glass tape, 65 mil Exane jacket, rated 600 volts, cable diameter 0.455".

Attachrent A

Page 1 of 3

IE Bulletin-77-05 November 8, 3.977 Test Scope The three tests performed by Sandia were composed of two sequential and one simultaneous exposure to LOCA environments.

In each case the equipment was exposed to radiation and thermal aging prior to operating under the simulated LOCA conditions.

Figures I and 2 describe the test profiles for sequential and simultaneous tests respectively (Sandia tests were designed to study synergis-ic effects).

Each of the tests satisfy the intent of IEEE 323-1974.

The assemblies were electrically loaded to 20 amperes and 600 volts at the start of the tests.

Insulation resistance and capacitance measurements were recorded during the tests to indicate damage.

The equipment assemblies with respect to the seque tial.and simultaneous

.tests performed were as follows',

Sequential Tests (Two}

Xulton Connector/ITT Cable Gulton Connector/Anaconda, Cable Bendix Connector/ITT Cable ITT Connector/ITT Cable 2.

Simultaneous Test (One}

ITT Connector/ITT 'Cable Bendix Connector/ITT Cable Bendix Connector/Anaconda Cable Test Results 1 Assembly

3. Assembly 2 Assrablies 1 Assaably 1 Assembly 1

Assumably 2 Assbqblies Both ITT Cannon connector assemblies and both Gultrn connector assemblies showed almost immediate damage, in terms of insulation resistance and capacitance.

as the 70 psig steam was applied.

The 'ITT Cannon connector assembly failures appeared to be back plane boot seal leakage failures.

The assembly construe-.ion did not contain potting 'compound (by design) to protect the pin ba"ks.

Therefore,. boot

'fai1ure leads'irectly to connector failure.-

In the case of the Gulton Assemblies, failures were attributed to both the mating surface interface and the back plane se=-l.

The design uses a rigid insert around the mating pins and the 0-ring'eals are Attachment A

Page 2 of 3

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'ovember 8,

1977 bypassed by an alignment key slot.

This design may lead to leaks due to non-uniform confinement of the 0-ring which could cause arcing between pins.

Neutron radiography revealed inad quate amounts of potting compound (voids) and cracking of potting compound.

These conditions could account

'or back plane failures.

Neutron radiography performed on untested connectors revealed similar conditions, i.e., voids and cracking, thus indicating an apparent quality control problem at Gulton s facility.

Other problems detected were identified as:

1.

The shrink tube used over the pin cable interface was split length-wise and had pulled away.

2.

The potting material showed virtually no adhesion to, or sealing

between, the cable jacket, insulation, and the connector shell.

3.

The.mechanical clamp had been secured so tightly.that it cut the

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cable jacket.

The Bendix connector assembly was the only type to survive an entire test cycle.

One Bendix/Anaconda assembly malfuncfioned after about eight days into the 10 psig profile and the Bendix/ITT assembly experienced decreasing resistance and increasing capacitance through the simultaneous tests until'oth readings were off sca'.e at the erd of the 10 psig profile.

A second Bendix/Anaconda assembly survived the sinultaneous tests.

During the sequential tests only Bendix and ITT Cannon assemblies were involved and both assemblies failed.

The failures of the'sa assemblies would be difficult to define as either connector or cable failures.

The ITT cable exhibited a shrinking characteristic which could Reve provided a.leak path through the sealing medium. of the connector,.

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IE Bulletin 77-05 November 8, 1977 r

Bullet',in tto.

Subject LISTING OF IE BULLETINS ISSUED IN 1977 Date Issued Issued To 77-X J7-D3 9/12/77 Cal cul ational Error ll/4/77 Affecting the Design Performance of a System for Controlling pH of Containment Sump Mater Following a LOCA-On-Line Testing of the M Solid State Protectiort System All PMR Power Reactor Facilities with an Operating License (OL) or Contruction Permit (CP)

All M Power

'eactor Facilities w'ith. an Operating License (OL) or Construction Permit (CP)

J7-02 Potential Failure Mechanism in Certain M AR Relays with

. Relays with Latch Attachments 9/12/77 All Holders of Operating Licenses (OL) or Construc-tion Permits (CP) 77-01 Pneumatic-Time Delay Set Point

'Drift 4/29/77 All Holders of Operating Licenses (OL) or Construc-tion Permits (CP).

Enclosure.2 Page 1 of 1

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e NUCLEAR REGULATORY CGti."llSS ION OFFICE OF INSPECTION ANO ENFOPCEHENT MASHINGTON, D. C.

20555 November -14, 1977 ELECTRICAL CONNECTOR ASSEtlBLIES IE Bulletin 77-05A Descri tion of Circumstances t

This Bulletin is a supplement to IE Bulletin 77-05, issued November 8, 197.

and the two documents should be considered together;.

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Bulletin 77-05 described. the failure, under test conditions, of a general'ype of electrical connector.

The tests were intended. to simulate post-LOCA conditions, therefore the action requested in the Bulletin focussed on the qualification of electrical connectors for use inside containment.

Since issu'ance of Bulletin 77-05; our attention has been called to circumstances which indicate that the scope of the action requested should be expanded and therefore the response to Bulletin 77-05 should reflect the expanded scope.

Electrical connectors should be qualified to perform their intended function after having been subjected to accident conditions if they are contained in a system whose function is to mitigate that accident.

The location of the connectors that must be qualified is not limited to those inside containment.

Action To Be Taken B

Licensees and Permit Holders:

Actions requested by Bulletin 77-05 should be expanded to include all connectors in safety systems which are required to function to mitigate an accident where the accident itself could adversely affect the ability of the system to perform its safety function.

The examination is not to be limited to only LOCA's nor to areas only within containment.

2.

Responses should be provided within 30 or 60 days, as appropriate,

.of the date of. this supplement.

Approved by GAO, B180225 (R0072); clearance expires 7-31-,80.

Approval was given under a blanket clearance specifically for identified generic problems..