ML20237C364
| ML20237C364 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 12/16/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237C248 | List: |
| References | |
| NUDOCS 8712210279 | |
| Download: ML20237C364 (5) | |
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UNITE D STATES lg-g p,
NUCLEAR REGULATORY COMMISSION
<j WASHINGTON, D. C. 20555
% %s l SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0.12 TO FACILITY OPERATING LICENSE NO. NPF-43 DETROIT EDISON COMPANY WOLVERINE POWER SUPPLY COOPERATIVE, INCORPORATED 1
FERMI-2 DOCKET NO. 50-341 c
1.0 INTRODUCTION
As a result of the emergency diesel generator (EDG) engine bearing failure which occurred in January 1985, the Detroit Edison Company (DECO 1
or the licensee) proposed an EDG engine lube oil surveillance test program to ensure the continued reliability of the EDGs.
The program was described to the NRC staff by DECO in letters dated March 6, March 14, and March 15, 1985.
The NRC staff's evaluation and acceptance of the l
proposed program were documented in Supplement No. 5 to the Fermi-2 Safety Evaluation Report (SER) (NUREG-0798) and the following license condition cited in the Ftrmi-2 Facility Operating License No. NPF-43 as Paragraph 2.C.(10):
DECO shall implement its commitments regarding the surveillance t
program for the lubricating oil system of the emergency diesel generators as described in its letters dated March 6, March 14, and March 15, 1985.
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The surveillance program required quarterly disassembly and inspection of each EDG engine oil filter and spectrographic analysis of the oil filter media as a means of predicting incipient bearing failures.
As a result of additional EDG engine bearing failures in November 1985, and December 1985, DECO proposed an augmented surveillance program which included periodic bearing inspections.
In its July 16, 1986, letter accepting the l
proposed augmented surveillance program, the NRC staff required, among other things, that a gap check be performed on the main bearing of each EDG eng'ne after every automatic unprelubricated (dry) start or every six months, whichever occurred first, and that a special visual inspection of the upper thrust bearing of EDG engine No. 13 be performed at the next scheduled 18-month Technical Specification surveillance, or at the time the envelope of engine starts established by the licensee's demonstration test program (described in DECO letter dated March 18, 1986) was exceeded.
In a letter dated October 14, 1986, the licensee committed to performing the bearing inspections as defined in the NRC staff's July 16, 1986, letter proposing that a time period of seven days be perr:itted to perform the bearing gap checks, and a time period of 30 days be permitted to perform the visual inspection of the P
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EDG No.13 engine upper main thrust bearing, to allow for flexibility in l
scheduling and performing these special inspections, and to avoid unnecessary plant shutdowns.
The staff accepted DECO's proposed timing for.the performance of these special inspections in a letter dated January 9,1987, with the condition that the plant be in the appropriate EDG Technical Specification limiting condition of operation (LCO) if the 1
window of test performance is ' exceeded, By letter dated January 28, 1987, DECO submitted a proposed license amendment to revise License Condition 2.C.(10) to delete from the EDG lube oil surveillance program, the requirement for the quarterly disassembly and inspection of engine lube oil filters and the spectrographic analysis of the oil filter c.edia; and to include in the amended license condition the special i
engine bearing-inspections discussed in the preceding paragraph above.
Following is a report of the staff's review, findings and conclusions relative to the January 28, 1987, license amendment proposal.
2.0 EVALUATION The current license condition (Paragraph 2.C.(10) of Facility Operating License No. NPF-43), which requires the implementation of the Fermi-2 EDG engine lube oil-surveillance program, consists of two major activities as follows:
(1) The quarterly disassembly, inspection and replacement of engine oil filters.
If bearing material is found in the oil filter, the main bearings of that engine are to be inspected, i.e., a gap check l
performed.
In addition, a spectrographic analysis is to be performed of the oil filter media and deposits that are found during the quartbrly inspection of the filter.
(2) The analysis of engine oil samples on a monthly basis for trend determinations.
By letter dated January 28, 1987, the licensee proposed deletion of surveillance relating to the lube oil disassembly, filter inspection and analysis.
The justification for this deletion was based on the accumulated data that have been obtained from the inspections performed to date.
DECO's evaluation of these data indicates that the lube oil filter inspections performed were ineffective in predicting incipient bearing failure.
It was for this reason that the lube oil filter disassembly, inspection, and oil filter media analyses were initially proposed.
As discussed in the staff's SER dated July 16, 1986 EDG Nos. 11 and 13 l
experienced bearing failures in late 1985.
The lube oil filter l
inspections / analyses prior to the bearing failures did not indicate any adverse conditions.
In addition, the inspection following the bearing failures revealed that numerous metallic fragments were visible prior to removing the lube oil filters from the filter vessel.
Upon completion of the disassembly of the filter media and subsequent spectrographic analysis, it was found that the detailed analysis was no more informative than the visual inspection of the exterior of the filter media.
Inspections performed I
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. since repairs of.the EDGs were made have also not revealed any new information concerning bearing status.
Additionally, the EDG vendor has recommended that the quarterly filter inspections be performed without the disassembly of the filter media and subsequent replacement of the filter.
DECO has indicated.that there is also an advantage to diesel operation with the. elimination of the frequent filter replacement.
Elimination of unnecessary filter changes will reduce the likelihood of contaminating the lube oil' system.
The licensee, although proposing deletion of the detailed filter media inspection, plans to continue the lube oil monitoring program.
To understand the significance of the licensee's proposal relative to the modification of the license condition, it is necessary to understand when bearing gap checks are required.
Currently, when a lube oil analysis
.or oil filter enalysis reveals unfavorable results (i.e., specified limits are exceeded), a EDG bearing gap check is required to be performed.
This is in addition to the normally required 18-month bearing gap inspection.
Also, following the late 1985 bearing failures, Deco committed to perform an EDG bearing gap check every six months or a gap check after every unplanned start, whichever occurs first, and an inspection of EDG No.13 upper thrust bearing as described in the staff's SER dated July 16, 1986.
It should be noted that the Fermi-2 license condition does not reference any of these required gap checks other than those that are identified through the lube oil surveillance program.
In summary, the licensee's rationale to support the modified and augmented EDG surveillance program is as follows:
The lube oil filter media inspection has not been effective in monitoring bearing condition.;
Examination of the filter exterior media will continue to be conducted on a periodic basis to provide information on the general condition of the filter; The increased frequency of gap checks as discussed above would be more effective in providing information about incipient bearing failure than would the quarterly disassembly and inspection of filter and filter media; Engine lobe oil sampling will continue to be performed and will provide relevant information on the condition of the oil; Elimination of quarterly filter replacement will reduce the potential for introducing contamination into the lube oil system.
In a letter. dated April 7, 1987, the licensee was informed of the NRC staff's agreement that there would be no safety benefit gained to continue to require the disassembly of the EDG engine oil filters quarterly as a means of predicting incipient bearing failure; and that the modified surveillance program proposed in the licensee's January 29, 1987 letter, augmenting Technical Specification surveillance test requirements, wculd
be sufficient for monitoring engine bearing conditions.
It was indicated in the April 7, 1987, letter, however, that the staff did not agree with the licensee's proposal that License Condition 2.C.(10) be revised by simply substituting, by reference, the January 28, 1987, letter for the March 1985 letters. The staff believed that the modified license condition should be self-explanatory, recommending that the license condition be modified as follows to encompass the proposed augmented surveillance program.
Emergency Diesel Generator (EDG) Engine Inspection Program (a) DECO shall perform gap checks on each EDG engine thrust bearing after every automatic, unprelubricated engine start or every six months, whichever occurs first, within seven days of the engine start.
The plant shall be in the appropriate Technical Specifi-cations LCO if the window of test performance is exceeded.
(b) Deco shall perform a visual inspection of the EDG No. 13 engine upper main thrust bearing at the next scheduled 18-month Technical Specification surveillance requirement, or at the time the envelope of engine starts established in the demonstration test program (described in DECO letter dated March 18, 1986) is exceeded, whichever occurs first, within 30 days from the time the inspection is scheduled to be performed.
(c) DECO shall analyze EDG engine lube oil samples monthly.
Should the samples analyzed identify foreign matter / deposits which could degrade engine bearing performance, Deco shall inform the NRC immediately and submit a report of analysis results and the detail corrective' action to be taken within 15 working days following such notification, i
By letter dated May 26, 1987, the licensee proposed the following alter-native license condition wording, which essentially agreed with the wording recommended by the NRC in its April 7,1987, letter, but which deleted q
subparagraph (b) relative to the visual injection of the EDG No. 13 engine 1
upper main thrust bearing:
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Emergency Diesel Generator (EDG) Engine Special Inspection Program (a) Detroit Edison shall perform gap checks on each EDG engine main bearing within seven days following every automatic, unprelubricated engine start, or every six months, whichever occurs first.
The six month check must be performed within six weeks of the six month interval due date.
The plant shall be in the appropriate Technical Specifications LCO if the window of test performance is exceeded.
l (b) Detroit Edison shall obtain and analyze, once each month, an engine lube oil sample from each EDG except when an EDG is unavailable for service.
Should each of two consecutive samples analyzed identify foreign matter / deposits which exceed Detroit
Edison established limits and which could degrade crankshaft bearing performance, the Licensee shall inform the NRC immediately and,, within 15 working days following such notification, submit a report of analysis results and the detailed corrective action to be taken.
The licensee. proposed to delete the EDG No. 13 visual inspection from the l
license condition because they had already performed that inspection, as required in the staff's SER dated July 16, 1986.
The inspection was observed by a representative from the NRC Region III office, the results of which are recorded in Inspection Report No. 50-341/87013 dated April 13, 1987.
l The regional inspector confirmed the results of the tests performed by the l
licensee on March 18, 1987.
These results are summarized in the licensee's l
On the basis of our review, we find that the license condition proposed i
in the licensee's letter dated May 26, 1987, is acceptable.
The monthly I
sampling of engine lube oil and bearing gap checks, coupled with current
' Technical Specification surveillance test requirements, will provide sufficient monitoring of EDG engine bearing performance.
- 3. 0 ENVIRONMENTAL CONSIDERATION This amendment involves changes to a surveillance requirement.
We have determined that this amendment involves no significant l
increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational radiation exposure.
The Commission has made a final no significant hazards consideration finding with respect to this amendment.
Accordingly, this amendment meets the eligibility criteria for categorical i
exclusion set forth in'10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b),
l no environmental impact statement nor environmental assessment need be prepared in connection with the issuance of this amendment.
4.0 CONCLUSION
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors:
A. Notafrancesco l
J. Stefano Dated: December 16, 1987
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