ML19345A452
| ML19345A452 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/17/1976 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 8011210600 | |
| Download: ML19345A452 (1) | |
Text
V.. vul.wlVW REGloN I I
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Yankee Atomic Ele tric Company Docket No. 50-29 ld Attention:
Mr. Robert H. Groce Licensing Engineer j k 20 Turnpike Road
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Westborough, Massachusetts 01581 l
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Gentlemen:
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Enclosed are IE Bulletin Nos. 76-02 and 76-03 which require action by i
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you with regard to your power reactor facility (ies) with operating M
licenr.c or construction permit.
f S'.ould you have cuestions regarding these Bulletins or the action re-r,uired of you, please contact this office.
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Sincerely,
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vt James P. O'Reilly i
Director j
Enclosures:
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1E Eulletin No. 76-02
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IE Eulletin No. 76-03 Approval of NRC requirements for reports concerning I
l possible generic problecs has been obtained under 44 1 [
j U.S.C. 3512 from the U. S. General Accounting Office (GAO b
i Approval 3-180255(R0072), expires 7/31/77).
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H. Autio, Plant Superintendent h
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_'.E Inspection and Enforcement Bulletin No. 76-02 March 17, 1976 RELAY COIL FAILURES - GE TYPE HFA, HGA, HKA, HMA RELAYS DESCRIPTION OF CIRCUMSTANCES:
A failure of a General Electric (GE) Type 12HEA51A42H Relay occurred recently in a safety related circuit at the Turkey Point facility. The relay failed during reactor safeguards systems testing.
Earlier fail-urcs of a similar nature involving GE type HGA relays were reported from Florida Pouer and Light Company in 1973.
The relay manufacturer has det..ained that open circuit coil failures of the relay windings had been caused by corrosion.
Halogens from a class of nylon coil spools (or bobbins) plus humid conditions were attributed as the funda ental causes of the corrosion and resulting coil failure.
The relays identified by the manufacturer which may have this nylon spool include HEA, HGA, EKA, HMA relay types, made by GE prior to 1969, l
and they may be identified by a white, nylon coil spool.
Portions of a l
GE service letter containing information about these relays are attached to this bulletin.
Further instructions regarding repair procedures can
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be obtained from the GE Service Engineering Department, Philadelphia.
ACTION TO BE TAKEN BY LICENSEES AND PERMIT HOLDERS:
Licensees of power reactor facilities with.an operating license or construction permit are to take the following actions:
i 1.
If you have received the attached GE service letter, describe what action you have taken regarding replacement of-the older style-nylon coil bobbins with the reco= mended Lexan type bobbins in the j
types of relays identified in the enclosed GE letter.
2.
If you have not received the attached GE service letter, describe what action you plan to take if relays of the type and vintage.
described in the enclosed GE lecter are in use cn planned for use in safety related systems.
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For facilities with operating licenses, a report of the above descriptions and plans, including the date when the actions were or
.I will be completed, should be submitted within 30 days af ter. receipt '
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For facilities with construction permits, a report of the above descriptions and plans, including the date when the actions were or
'm will be completed, should be submitted within 60 days after receipt of this bulletin.
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Reports should be submitted to the Director of the NRC Regional Office
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and a copy should be forwarded to the NRC Office of Inspection and Enforccment, Division of Reactor Inspection Programs, Washington, D. C.
20555.
Approval of NRC requirements for reports concerning possible generic problems has been obtained under 44 U.S.C. 3152 from the U. S. General i
Accounting Office.
(GAO Approval B-180255(R0072), expires 7/31/77)
ATTACIBfENT:
Extract from General Electric Service Letter:
HFA, HGA, HKA, EXA RELAYS NYLON COIL BOBBINS e
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L-IE Bulletin Number 76-02 ATTACHMENT A EXTRACT FROM GENERAL ELECTRIC SERVICE LETTER HFA, HGA, HKA, HMA RELAYS NYLON COIL BOBBINS In 1954, a program,was initiated to improve the mechanical and elec-trical properties of paper based spools used for HFA, HGA, HKA and HMA relay coils. Heat stabilized nylon was selected for the spool material because its temperature characteristics made it well suited for Class A coils, and the material provided the desired improvement in electrical and mechanical properties. Manufacturing of HMA relays with the nylon spools started in 1955.
After three years of successful experience, the change to nylon spools was implemented in HFA, HGA, and HKA relays in 1958.
In the mid 60's, a few failures of HMA coils utilizing the nylon spools for DC applications were reported. As a result of these failures, an investigation was undertaken to determine the cause of the failures.
It was found from this investigation that the heat stabilizing element of the nylon coil spool contained halogen ions which could be released over a period of tiue.
When combined with moisture, the halogen ions form hydrocloric acid and copper salts which could cause the eventual open circuit failure of the coils.
I The most significant contributing factor in the reported failures is
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high humidity.
Other contributing factors are the small wire cize used
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in FDM relays and in DC relays, and the release of halogen ions is accelerated by DC potential.
Relay coils which are continuous 1 energized j
are not subject to this phenomenon because the coil temperature is y
maintained considerably above ambient, thus minimizing the probability e
of moisture getting into the coil.
After the spool material was changed to nylon in 1955-58, a new mate-j rial, Lexan, became avaliable.
Lexan has the desired chemical, mech-anical and electrical characteristics for use in spools.
The change to the use of Lexan for spools was started in 1964 and completed in-1968.
The first relay changed was the HMA followed by the HGA and HFA. Black was chosen for the color of Lexan spools to make them distinguishable from the nylon.
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Since the initial report of open circuited letA coils, the failures of f
TE However, recently one customer auxiliary relays has been very limited.
$h failures of a significant reported an accumulation of open circuit si number of HGA relays with nylon spools which were used in X-Y closing d
circuits of breakers.
As' a result of this recent report and in keeping with our procedure of informing you of potential problems, we are bring-ing this matter to your attention, even though the overall rate of failure continues to be extremely low.
If you have applications of HFA, HGA, HYA, and letA relays in areas of and with white nylon high humidity, intermittent operation, DC power, spools, you may wish to consider replacing the coils or relays.
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Inspection and Enforcement Bulletin No. 76-03 March 17, 1976 m.
' bI RELAY MALFUNCTIONS - GE TYPE STD RELAYS E
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DESCRIPTION OF CIRCUMSTANCES:
i A malfunction of a General Electric (GE) Type 12STD15B5A Relay occurred recently in a safety related load center at Joseph M. Farley Station.
F The relay malfunction was due to radio frequency interference from an activated transceiver.
This malfunction tripped the circuit breakers to-isolate the associated transformer which resulted in the removal of the f
incoming power to the 600 volt load center.
Three other users of these devices have reported STD relay malfunctions due to radio frequency E.
interference.
In addition, there have been several cases of failed-L shorted components on the STD relay amplifier card which resulted in relay malfunction.
The STD type relay may be installed in similar 1
applications at BWR or PWR facilities.
The relays involved were in-E
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itially marketed in 1968.
Portions of a GE service letter containing information about these relays are attached to this bulletin. Further instructions regarding repair procedures can be obtained from the GE Service Engineering Department, Philadelphia.
ACTION TO BE TAKEN BY LICENSEES AND PERMIT HOLDERS:
Licensees of power reactor facilities with an operating license or construction permit are to take the following actions:
1.
If you have received the attached GE service letter, describe what action you have taken regarding the recommended action to update your existing STD relays identified in the enclosed GE letter.
2.
If you have not received the attached GE service letter, describe what action you plan to take if relays of the type and model de-scribed in the enclosed GE letter are in use or planned for use in safety related syste=s.
3.
For facilities with operating licenses, a report of the above descriptions and plans, including the date when the actions were or will be completed, should be submitted within 30 days after recei.
t of this bulletin.
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For facilities with construction permits, a report of the above
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descriptions and plans, including the date when the actions were or-will be completed, should be submitted within 60 days after receipt of this bulletin.
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S-Reports should be submitt'ed to the Director of the NRC Regional Office and a copy should be forwarded to the NRC Office of Inspection and Enforcement, Division of Reactor Inspection Programs, Washington, D. C.
20555.
i Approval of NRC re.irements for reports concerning possible generic problems has beer. obtained under 44 U.S.C. 3152 from the U. S. General-Accounting Offlue.
(GAO Approval B-180255(R0072), expires 7/31/77)
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ATTACHMENT:
E Extract from General Electric Service Letter:
STD RELAYS TRANSFORME3 DIFFERENTIAL RELAY F
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IE Bulletin Number 76-03 ATTACIMENT A
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EXTRACT FROM GENERAL ELECTRIC SERVICE LETTER S
3 STD RELAYS
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TRANSFORMER DIFFERENTIAL RELAY In line with our policy of keeping users informed of conditions which r.
4 could possibly affect relay operation, the following information is
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provided on type STD transformer dif ferential relays.
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-4 Three customers have reported that the zener diodes er the associated i
dropping resistors on the STD Sense Amplifier Card have failed shorted.
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The problem has been traced ts two zener diodes whose cases have hotn physically touching, short circuiting one diode and overloadir.g the 1
circuit. There are several possible causes of such isolated failures fj
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including the possibility of mishandling during test.
Incorrect STD p
relay trip outputs are associated with such a failure in this circuit.
1 Tests have shown that, with these components touching, the STD relay is E
I also vulnerable to misoperation on DC transients.
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i Because of these reported problems, it is suggested that the clearance 2
_j between the two IN3024 diode cases and other component lead clearances on the sense amplifier card be visually inspected during routine STD p
4 test or maintenance.
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l When the probles was initially reported, insulating tubing was added to j
the zener diode in our manufacturing process as a future safeguard to prevent possible short circuiting due to deformation of the zener diode p
leads. Subsequently, to further improve the STD relay, the sense ampli-c fier card has been redesigned using a new printed circuit card with I
components arranged to preclude any possibility of short circuiting.
At the same time the card had been redesigned to improve the card f
layout, the STD dropout time was reduced to 32 milliseconds and its p
radio frequency sensitivity was reduced significantly.
Thus, an updated s
relay will pass the RFl and Fast Transient tests, and, of course, the standard IEEE Surge Withstand Capability test.
In addition, a change in h
nameplate design makes the output contacts more visib1c.*
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. The new sense amplifier card is identified as #0108B9305 G-4. This new card will become a standard feature in all STD relays shipped after December 1, 1975. At that time the STD model numbers will be changed in accordance with the attached list to reflect these changes, and the new relay models will be automatically substituted on unfilled orders.
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Existing STD relays now in service can be updated with a new amplifier
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card, associated dropping resistors and minor wiring changes.
- None of these design improvements affect the basic operating prin-
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ciples of the STD (operate on fundamental, restrain on all harmonics) nor do they change the restraint level from 20% harmonics.
These prin-ciples have been proven effective on over 35,000 G.E. harmonic restraint transformer differential relays, including those applied to transformers with the new high permeability core steel.
A reduction in the level of k
harmonic restraint is not desirable, as it would degrade performance (desensitize the relay in detecting f aults during energizing) with no offsetti.'g benefit.
OLD MODEL NUMBER NEW MOD..
NIHBER KIT NUMBER 12STD15BIA 12STD15C3A 0152C9069 G1 12STD15B2A 12STD15C2A 0152C9069 G2 12STD15B3A 12STD15C3A 0152C9069 G3 12STD15B4A 12STD15C4A 0152C9069 G4 12STD15B5A 12STD15C5A 0152C9069 G5 t
12STD15B6A 12STD15C6A 0152C9069 G6 I
12STD16BIA 12STD16C3A 0152C9069 G7 l
I 12STD1632A 12STD16C4A 0152C9069 G8 E
12STD1653A 12STD16C3A 0152C9069 G9 12STD1631A 12STD16C4A 0152C9069 G10 12STD1635A 12STD16C5A 0152C9069 Gil 12STD1636A 12STD16C6A 0152C9069 G12 12STD1637A 12STD16C7A 0152C9069 G13 12STD17BIA 12STD17C2A 0152C9069 G14 12STD17B2A 12STD17C2A 0152C9069 GIS 12STD18BIA 12STD18C2A 0152C9069 G16 12STD18B2A 12STD18C2A 0152C9069 G17 12STD18B3A 12STD18C3A 0152C9069 G18 12STD18B4A 12STD18C4A 0152C9069 G19 12STD21BIA 12STD21 CIA 0152C9069 G20
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7 OLD MODEL NLYdER NEW MODEL NUMBER-KIT NUMBER i-12STD25B1A 12STD25D2A 0152C9069 G21 12STD25B2A 12STD25D2A 0152C9069 G22 L'
12STD25 CIA 12STD25E2A 0152C9069 G23 12STD25C2A 12STD25E2A 0152C9069 G24 l
12STD26BIA 12STD26 CIA 0152C9069 G25 4
12STD28 BID 12STD28C1D 0152C9069 G26 p
12STD28B2D
-12STD28C2D 0152C9069 G27 L
12STD29B1D 12STD29C1D 0152C9069 G28 l
12STD29B2D 12STD29C2D 0152C9069 G29 E
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