ML16340A657
| ML16340A657 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 11/02/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7911190194 | |
| Download: ML16340A657 (22) | |
Text
gp,8 REJIG(
Wp
/p ++*++
UNITED STATES NUCLEAR REGULATORY COMMISSION REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202, WALNUTCREEK PLAZA WALNUTCREEK, CALIFORNIA94596 November 2, 1979 Docket Nos.
50-275 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention:
Nr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
Enclosed is IE Bulletin No. 79-25 which requires action by you with regard to your power reactor facility(ies) with an operating license or '
construction permit.
Should you have questions regarding this Bulletin or the actions required of you, please contact this office.
Sincerely, R.
H. EngelkeTI~
Director
Enclosures:
1.
List of IE Bulletins Issued in the Last Six Months cc w/enclosures:
J. Worthington, PG&E W. Raymond, PGSE R.
- Ramsay, PG8E, Diablo Canyon
'1h, L
t$
F
UNITED STATES SSINS No.:
6820 NUCLEAR REGULATORY COMMISSION Accession No.:
OFFICE OF INSPFCTION AND ENFORCEMENT 7908220139 WASHINGTON, 0.
C.
20555 November 2, 1979 IE Bulletin No. 79-25 FAILURES OF 1!ESTINGHOUSE RFQ RELAYS IN SAFETY-RELATED SYSTEMS Description of Circumstances:
~lhi Ie conductinq response time tests on Westinghouse BFD relays at the H.
B.
Robinson facility, toto relays were found to be stuck in the enerqized position with the coil de-energized.
The twenty relays being tested were installed soares and provided no safety-related or operational function.
The subiect relay is identified as a Mestinghouse Electric Corporation type BFD, style 5069A95603, coil stvle 1259C71619.
Upon discovery of the two stuck relays in the test pro-
- qram, the licensee conducted response tests on similar relays installed in the Reactor Protection System.
Durinq this additional testing a reactor trip relay was fnund to be stuck in the energized position.
Detailed investigation of the problem by the licensee's staff indicated that the armature was sticking to the armature stop post.
This condition is apparently created when heat generated by normally energized coils causes a softening and resultant flow of epoxy adhesive used to attach the magnetic anti stick disc to the top of the armature stop post.
Nhen sufficient adhesive flows to the top of the armature stop, the armature becomes bonded to the stop post, resultinq in the relay stickinq in the energized position.
The epoxy adhesive had also discolored to a dark broom as opposed to clear in new relays.
After reviewinq this problem, !lestinghouse issued a service letter dated December 6, 1978.
A copy of this letter is enclosed for your information and approoriate use.
Mestinghouse recommended replacing affected relays with a relay identified as NBFD, style 5072A49, coil style 1271C50601, 125/130 Volt DC
/ 10 percent.
During installation and testing of the new NBFD relays identified by Westinghouse, H. B. Pobinson determined that some of the new style relays exhibited marginal or unsatisfactory armature overtravel.
An investiqation of the problem by
'l!estinqhouse indicated that the insufficient overtravel was limited to eight and twelve pole models of the NBFD relays.
Westinghouse issued a Technical Bulletin NSD-T8-79-05 to Licensees.
A copy of this Technical Bulletin is also enclosed for your information and use.
Mestinghouse recommended a testing method for identifyinq relays with insufficient over travel and also recommended replace-ment of relays with insufficient overtravel.
Action to be Taken by Licensees:
For all power reactor facilities with an operatinq license or construction nermit:
1.
Determine whether or not the follo~vinq Hestinghouse BFD/NBFD relays are used or planned for use in safety-related systems at your facilities:
a.
Tyne BFD, style 46E7352 or 766A235, coil style 503C428621 b.
Type BFD, style 5069A95, coil style 1259C71G19 c.
Type BFD, style 5072A49, coil style 1271C50G01
1
IE Bul'letin Ho. 79-25 November 2, 1979 Page 2 of 2 2.
If such relays are used or planned'or use, identify the safety-related systems involved, specific function of relays and provide in written form your olans for a test and/or:replacement program which will assure design oerformance of affected relays.
3.
The orogram to assure performance of affected relays shall include, but not be limited to the following:
b.
C.
d.
Establishment and adherence to a periodic testing and/or reolacement schedule to assure operability of applicable relays.
The basis for the test interval of 3a.
above includinq the data base upon which the initial test schedule is established.
Development of approved procedures to be utilized by qualified person-nel for the testing and/or replacement of applicable relays.
Relay failures found during program testing are to be documented in final report and reported at the time of finding in accordance with license requirements.
4.
For facilities with an operating license, a written report of the above
- actions, includino date(s) when they will be completed, shall be submitted within 45 days of receipt of this Bulletin.
5.
For facilities with a construction permit, a written report of the above
- actions, including the date(s) when they gill be completed, shall be sub-mitted within 60 days of the receipt of this Bulletin.
Reports should be submitted to the Director of the approoriate NRC Regional Office.
A copy of your report should be sent to the U. S. Nuclear Regulatory Coomission, Office of Inspection and Enforcement, Division of Reactor Operation Inspection, Ifashington, D. C. 20555.
Aporoved by GAO, 6180225 (R0072); clearance exnires July 31, 1980.
Approval was given under a blanket clearance specifically for identified generic problems.
Enclosures:
1.
Extract from >Jestinghouse Service Letter TS-E-412, Dated December 6, 1978 2.
Extract from Mestinghouse Technical Bulletin, NDS-TB-79-05
0
EXTRACT OF WESTINGHOUSE LETTER TS-E-412, DECFt1BER 6, 1978 An ooerating nuclear plant recently encountered difficulties with BFD relays, and follow-un investigation revealed that the relays involved were not the latest, currently recommended version of the relay.
As indicated in our Technical Bulletin NSD-TB-78-16, the improved recommended relay is identified as follows:
NBFD relay-Style No. 5072A49, Series (State pole configuration required).
Coil - Style No. 1271C50801 125/130 volt DC / 10 percent.
(Note:
These relays are currently identified by the manufacturer as "NBFO" relays.
However, it is possible that some of the earlier relays of this type manufactured in early 1977 did not include the "N" prefix.)
This relay has been available only since December 1976.
Prior to that time, the 125/130 volt BFD relays in use were Style 766A235 with Style 503C428G21 coils (until 1973),
and Style 5069A95 relays, with Style 1259C71G19 coils (from 1973 until December 1976).
He recormend that either of these relays, in a safety-related application, should be replaced by relays identified in the second oaragraph above.
Our earlier recnrmenrlation in TB 76-16 indicated that only normally-energized relays need be replaced.
This is still a justifiable position.
However, for uniformity Enclosure 1
4
Enclosure 1
Page 2 of 2 purposes and for an added measure'f reliability, customers may wish to install these recormended relays in all safety-related applications whether normally energized or normally de-energized.
In any case where older style 8FD's are still in service in normally energized safety-related applications, we reiterate the recommendation stated in TB-76-16 and 76-5 that the relays be visually checked for free operation during periodic testing.
At the next convenient pla'nt shutdown, the recommended relays should be installed.
EXTRACT OF MESTINGHOUSE TECHNICAL BULLETIN, NSD-TB-79-05 BACKGROUND INFORMATION The referenced 1976 Technical Bulletin described problems saith type BFD (dc) control relays, and identified a new improved style of BFD relays which were designated for greater reliability.
The new device was identified as relay style number 5072A49 (followed by the letter G and a two-digit number, denending on pole configuration), with coil style number 1271C50G01.
This new relay was first made available in'ecember of 1976; thereafter, they were identified as "NBFD".
In mid-1978, initial reports were received that some of the new style relays exhibited marginal or unsatisfactory contact-making characteristics due to insufficient armature travel, which results in insufficient overtravel of the movinq contact.
The manufacturing division (Westinghouse Standard Control Division) originally felt that the problem was limited to a relatively narrow "batch" of relays, and cer tain users were so notified.
However, recent revela-tion of additional causes of relays with insufficient overtravel indicates that all eight pole relays
(."models 44, 62, 26, 80, etc.)
and all twelve pole relays
(!1odels 66, 84, 48, 120, etc.) of this style should be considered suspect until contact overtravel can be confirmed by measurement, or the relays are replaced with relays known to have adequate overtravel.
Four pole relays (Hodels 22, 31, 13, 40, etc.)
may be excluded from the measure-ment and the concern described above since they utilize a different armature not susceptible to the potential travel problem.
Fnclosure 2
Enclosure 2
Page 2 of 3 RECOt<!IFNDFD ACTION Relays in question are all eight pole and twelve pole NBFD relays, or any BFD relay style number 5072A49.
G** (except four pole relays 601, G02, G03, G04, 616 and 619) with coil style number 1271C50G01.
Any such relay in storage, or installed in a safety-related application, must be checked at the earliest possible opportunity to confirm adequate contact overtravel.
The manufacturer has established 0.020 (twenty thousands) inch as the minimum acceptable overtravel, with overtravel beino defined as the distance the relay armature travels beyond the point at which normally ooen (n.o.) contacts make.
In multi-pole relays, the overtravel definition applies to the last n.o. contacts to physically close.
Me recognize that the measurements described above may mean removal of the relays.
Any relays showing inadequate overtravel should be returned to Mestinghouse for rework or replacement.
The following points may be of assistance in making the above measurements:
?
Disassembly of the relay in order to make the overtravel measurement is not necessary.
Armature travel, as taken from the cross-bar or the top "button" maybe used as an indicator of moving contact travel.
4
Enclosure 2
Page 3 of 3
?
Electrical operation of the relay in order to make the measurement is not I
necessary.
Manual operation of the armature provides the same amount of travel as is obtained in electrical operation.
?
The relay need not be in its normal armature-horizonal position in making the measurement.
For purposes of this test, vertical travel of the armature will not significiantly affect overtravel characteristics.
Although the manufacturer has not established a maximum acceptable over-travel, personnel obtaining the measurements may be interested in knowing that forty-seven thousandths was the desiqnated overtravel, and as much as 50 and 60 thousandths has been found on normal relays.
Use of the denth gauge position of a dial vernier caliper has been found to be a convenient method of measurino the overtravel, with lamp and battery (maximum of six volts and minimum of three volts) circuit indicating closure of the contacts in series.
Note:
Subsequent to issuance of the above information by l<estinghouse, it has been determined by tests performed by H. B. Robinson that a pre-liminary check of in-rack relays is acceptable.
This preliminary check can be performed with a six-inch pocket scale with 1/64 inch increments.
If armature overtravel is less than 1/32 inch, the relay should be tested further as described above.
ilormal overtravel measured hy this preliminarv check is approximately 1/16 inch.
0
iF. Bulletin No. 79-25 November 2, 1979 Encl osure Page 1 of 3 Bulletin No.
79-24 Subject Frozen Lines LISTING OF IF. BULLFTINS ISSUFD IN LAST SIX flONTHS flate Is'sued 9/27/79 Issued To All power reactor facilities which have either OLs or CPs and are in the late stage of construction 79-23 Potential Failure of Emergency Diesel Generator Field Exciter Transformer 9/12/79 All Power Reactor Facilities with an Operating License or a construction oermi t 79-14 Seismic Analyses For (Supplement
- 2) As-Built Safety-Related Piping Systems 9/7/79 All Power Reactor Facilities with an OL or a CP 79-22 79-13 (Rev.
1)
Possible Leakage of Tubes of Tritium Gas in Time-pieces for Luminosity Cracking in Feedwater System Piping 9/5/79 8/30/79 To Each Licensee who Receives Tubes of Tritium Gas Used in Timeoieces for Luminosity All Designated Applicants for OLs 79-02 Pipe Support Base Plate (Rev.
1)
Designs Using Concrete (Suonlement
- 1) Expansion Anchor Bolts 8/20/79 All power Reactor Facilities with an OL or a CP 79-14 (Supplement) 79-21 79-20 79-19 Seismic Analyses For As-Built Safety-Related Pining Systems Temperature Effects on Level Measurements Packaging Low-Level Radioactive h'aste for Transport and Burial Packaging Low-Level Radioactive Waste for Transport and Burial 8/15/79 8/13/79 8/10/79 8/10/79 All Power Peactor Facilities with an OL or a CP All P!fRs with an operating license All Materials Licensees who did not receive Bulletin No. 79-19 All Power and Research Reactors with OLs, fuel facilities except uranium mills, and certain materials licensees
,IE Bulletin No. 79-25 November 2, 1979 Enclosure Page 2 of 3 Bul le tin No.
Subject LISTING OF IE BULLETINS ISSUED IN LAST SIX NONTHS Date Issued Issued To 79-18 Audibility Problems Encountered on Evacuation 8/7/79 All Power Reactor Facilities with an Operatinq License 79-05C506C Nuclear Incident at Three 7/26/79 Nile Island - Supplement To all PMR Power Reactor Facilities with an OL 79-17 Pipe Cracks in Staqnant Borated Mater Systems at PMR Plants 7/26/79 All PMR's with operating license 79-16 Vital Area Access Controls 7/26/79 All Holders of and aoplicants for Power Reactor Operating Licenses who anticipate loadina fuel prior to 1901 79-14 (Revision 1) 79-15 79-14 79-13 79-02 (Rev.
1)
Seismic Anal.yses For As-Built Safety-Related Pioina System Deep Draft Pumo Deficiencies Seismic Analyses for As-Built Safety-Related Piping System Crackinq In Feedwater System Piping Pipe Support Base Plate Designs Usinq Concrete Expansion Anchor Bolts 7/18/79 7/11/79 7/2/79 6/25/79 6/21/79 All Power Reactor Facilities with an OL or a
CP All Power Reactor Licensees with a CP and/or OL All Power Reactor facilities with an OL or a CP All PMRs with an OL for action. All BIJRs with a CP for information.
All Power Reactor Facilities with an OL 'nr a CP
4 r
1
-JE. Bulletin No. 79-25 Novemher 2, 1979 LISTING OF IF. BULLETINS ISSUED IN LAST SIX f<ONTHS Encl osure Page 3 of 3 Bul 1 etin No.
Subject Date Issued Issued To 79-01A Environmental Dual ification of Class lE Equipment (Deficiencies in the Envi-ronmental gualification of ASCO Solenoid Valves) 6/6/79 All Power Reactor Facilities with an OL or CP
0 0
E
~,'/l
't