ML20137B708
| ML20137B708 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 02/26/1985 |
| From: | Andrews R OMAHA PUBLIC POWER DISTRICT |
| To: | Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| IEB-84-02, IEB-84-2, LIC-85-045, LIC-85-45, NUDOCS 8508220121 | |
| Download: ML20137B708 (6) | |
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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102 402/536-4000 February 26, 1985
@@h LIC-85-045 1
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Mr. Robert D. Martin Regional Administrator U. S. Nuclear Regulatory Commission U
Region IV i
611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011
References:
(1) Docket No. 50-285 (2)
IE Bulletin 84-02, dated March 12, 1984 (3) Letter OPPD (R. L. Andrews) to NRC Region IV (Mr. J. T. Collins) dated July 17, 1984 (LIC-84-225)
Dear Mr. Martin:
IE Bulletin 84-02:
Failure of General Electric Type HFA Relays in Use in Class 1E Safety Systems In the attachment to Reference (3), the Omaha Public Power District responded to concerns raised in Reference (2).
The District stated that certain HFA relays would be replaced prior to March,1986.
In the " Background" section of Reference (2), it was stated that replacement of the coil spools or replacement of the en-tire relay were considered equivalent.
The purpose of this letter is to confirm the District's corrective actions to resolve Reference (2) concerns. The District has opted to replace the relay coils rather than the entire relay.
Consequently, the attachment to Reference (3) is hereby resubmitted with the appropriate changes made to reflect this. The attachment is stated as "either/or" to allow for the replacement of either the coil or the entire relay if deemed appropriate. The changes are denoted by vertical lines in the right hand margin.
.f S1 re y, 8S08220121%8$285 iftM PDR ADOCK PDR R. L. Andrews o
Division Manager Nuclear Production RLA/DJM/dao Attachment cc:
U. S. Nuclear Regulatory Commission Document Control Desk LeBoeuf, Lamb, Leiby & MacRae
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1333 New Hampshire Avenue, N.W.
Washington, DC 20036 i
Mr. E. G. Tourigny, NRC Project Manager Mr. L. A. Yandell, NRC Senior Resident Inspector e mpmumengangagopponunay as sie4
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
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Omaha Public Power District
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Docket No. 50-285 (Fort Calhoun Station,
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Unit No. 1)
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AFFIDAVIT R. L. Andrews, being duly sworn, hereby deposes and says that he is Division Manager - Nuclear Production of the Omaha Public Power District; that he is duly authorized to sign and file with the Nuclear Regulatory Commission the attached revised attachment to the District's letter to the NRC in response to IE Bulletin 84-02 dated July 17, 1984 (LIC-84-225); that he is familiar with the content thereof; and that the matters set forth therein are true and correct to the best of his knowledge,information and belief.
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/e w R. L. Andrews Division Manager Nuclear Production STATE OF NEBRASKA)) ss COUNTY OF DOUGLAS)
Subscribed and sworn.to before me, a Notary Public in and for the State of Nebraska on this gre day of February, 1985.
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1 FNotary Public (f
Attachment Response to IE Bulletin 84-02 Request 1.
Plants in Operation a.
Develop plans and schedules for replacing (1) nylon or Lexan coil spool-type HFA relays used in normally energized safety-related*
applications and (2) nylon coil spool-type HFA relays used in normally de-energized safety-related applicattor.s. The replacement program for energized and de-energized relays should be performed on a "best efforts" basis during plant outages of sufficient duration. The entire replacement program should be completed within two years from the date of this bulletin.
The replacement schedule should consider the following recanmended priori ty:
Nylon or Lexan normally energized in the reactor trip system Nylon or Lexan normally energized in other safety-related appli-cations Nylon.normally de-energized in the. reactor trip system Nylon normally de-energized in other. safety-related applications District Response The District will replace all safety-related HFA relays or relay coils described in la above prior to March 1986. The replacement schedule will generally follow the above recanmended priority list.
Request b.
During the period before relay replacement, develop and implement surveillance plans that include:
(1)
Monthly functional tests of all reactor trip system normally energized relays that verify relay contacts change state when the relay. coil is de-energized; (2)
Visual inspections of all safety-related normally energized relays as soon as practical upon receipt of this bulletin.
Thereafter, similar inspections should be accomplished in conjunction with the monthly functional test. These visual inspections should verify that relay coils are not deterior-ating (e.g., inspect coil bobbins for visible cracks or melting), and should confirm cleanliness.of the relay n.le
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- Since GE asserts that the new Century Series HFA relay has been successfully tested to the environmental and seismic requirements specified in IEEE-323-1974 and IEEE-344-1975 Standards, this relay, or one of equal qualification, may be an acceptable replacement for Lexan/ Nylon HFA relay now in service at many nuclear power plants.
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District Response'
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The District does not presently use HFA relays on the reactor trip system. Therefore, no additional monthly functional tests are requi red.
For the balance of the Fort Calhoun Station, HFA relays in other systems are tested on a monthly basis in cases where design basis is such that monthly tests are practical. An example of such tests are the Ventilation Isolation Relays. The visual inspection, referenced above, is believed to be adequate for those relays not tested monthly (for example, the containment isolation relays). The District has conducted a visual inspection as requested by the Bulletin. The results of this visual inspection indicate that the HFA relays do not appear to be deteriorating.
Visual inspections have been conducted on a monthly basis since July 1984 and will continue to be conducted until the relay or relay coil r'eplacement can be completed to reconfirm the results of the initial visual inspection.
Request c.
Provide a basis for continuing operation for the period of time
'until the normally energized relays are replaced. This basis should include a discussion on those measure addressed in Items la and Ib and any other preventive and/or corrective measures taken or pl a nned.
District Response OPPD's operating experience with.HFA relays has been very good. A review of electrical equipment related maintenance orders to determine those concerning HFA relays has been conducted. The results of those maintenance orders reviewed indicated that of approximately 260 HFA relays in use at Fort Calhoun Station, one relay had a single crack in the spool piece and was subsequently l
repaired. This relay was found during a November 1981 inspection.
It should be noted that the relay was totally operational.
OPPD's experience with HFA relays in similar applications in fossil units and substations has also been very good.
HFA relays in these applications have been in use for periods of time th?t exceed that of Fort Calhoun Station. Operation failures have not significantly increased with age for fossil units and substation applications.
Failures of HFA relays beyond random failure (accounted for in redundant design) are not expected before the replacement of the relays or coils is completed.
Also, as HFA relays are not utilized in the Reactor Trip System at Fort Calhoun, they cannot contribute to nor be the precursor of an ATWS event.
Operating experience, reliability coupled with redundancy, and monthly visual inspections until replacement of the relays or coils
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combine to provide reasonable assurance that continued operations of the Fort Calhoun Station will not impact the health and safety of the public and is, therefore, justified.
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. Request (d)
If your plant uses or plans to continue to use the nylon or Lexan-
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type HFA relay in systems other than those safety-related applica-tions defined in this bulletin, then the appropriate administrative controls dealing with maintenance, storage, and handling of spare parts at your facility must be revised to ensure that the older and problematic HFA relay coils are not inadvertently used as a replace-ment part in safety-related applications in future maintenance efforts at your facility.
District Response OPPD implemented a program on August 1,1984, whereby only quali-fied HFA relay parts are stocked in the Fort Calhoun Station store-room. As these qualifled replacement parts will fit both types of HFA relays, (the safety-related and qualified relays, and the non-safety-related unqualified relays), this will preclude the possi-bility of mishandling the older unqualified relay parts.
Additionally, the bulletin contains a request for relayWnformation of a generic nature.
Specifically:
"Although the specific details involving the iden-tified relay failures described above may not directly apply to your facility (f es), you are asked to review the general concerns expressed in the bulletin for applicability at your facil-i ty( t es). For example, if a different type of relay is used for the same safety functions des-cribed in this bulletin, or relays with similar materials are used for other safety-related functions, past operating history and the man-ufacturer's recommendations should be reviewed to determine if additional action is appropriate.
Your response should describe the results of the review, and, if the general concerns apply, you should describe the short-term and long-term cor-rective actions to be taken and the schedules thereof".
The District has conducted a preliminary review of the operating history of other relays in use at the Fort Calhoun Station. The review included a review of the LER's submitted from 1976 to 1983.
As a result of this preliminary review, the District is planning to conduct an additional investigation of the "86 lockout" relays.
The District plans to conduct this additional investigation during the upcoming months. The District will evaluate the results of the above mentioned investigation and take the necessary action. Also, the District has contacted the vendors of relays in use at Fort Calhoun Station to determine if any aging or lifetime data exists.
The District believes that participation in such programs as NPRDS and vendor interface will lead to early identification and resolu-tion of equipment problems.
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The District also believes that equipment installed at the Fort Calhoun Station is reliable, and suitable for its intended service.
The USAR and related documents provide for this adequacy.
In addition, the District believes that this has been born out by excellent operating history. Programs such as surveillance test-ing, preventive maintenance, equipment history, NPRDS, etc., will ensure safe operation.
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