ML18058B308
| ML18058B308 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/22/1992 |
| From: | Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9301050194 | |
| Download: ML18058B308 (6) | |
Text
consumers Power POW ERi Nii MICHlliAN"S PROliRESS Palisades Nuclear Plant:
27780 Blue Star Memorial Highway, Coven. Ml 49043 December 22, 1992 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
GB Slade General Manager CHANGE IN COMMITMENT - ELECTRICAL DISTRIBUTION SYSTEM FUNCTIONAL INSPECTION REPORT COMMITMENTS - NRC INSPECTION REPORT No. 91019 The NRC conducted a special inspection of the electrical distribution system (EDSFI) at the Palisades Plant from November 4, 1991 to December 13, 1991 and documented in Inspection Report (IR) 91019, dated January 31, 1992.
By letter dated March 31, 1992, Consumers Power Company responded to the open items identified in IR 91019 and commitments regarding the open items. A change to two of those commitments is discussed below.
The changes consist of extensions to the previously scheduled completion dates for the open items.
The extensi.on of the scheduled completion dates is necessary due to the increased emergent workload on the Systems Engineering staff as a result of unanticipated plant transients.
In the following paragraphs the two NRC open items from IR 91019 are repeated, followed by the CPCo response and proposed corrective action from our March 31, 1992 letter. The last section under each of the open items is a
- description and reason for the change in commitment.
Open Item 91019-22 Inspection Report Paragraph 3.3.1.1 - Fuel Oil Supply System The team identified the following discrepancies in the design documentation associated with the EDG fuel oil storage tanks:
Fuel consumption tests were not documented.
- ' The calculations regarding the capacities of the EDG day tanks and belly tanks were inconsistent.
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.e The low level day tank alarm setpoint did not provide an accurate tank inventory.
The UFSAR, TS and various engineering analyses stated different EDG running time capabilities.
2 The team noted that the day tank emergency supply lines and their external valves DE-115 and 116, were not included in a maintenance and testing program to assure their availability at all times.
The supply lines provide compensation for the fact that storage tank T-10 and its appurtenances are not seismically or0 tornado qualified.
The team was also concerned that the TS required minimum 16,000 gallons of fuel in storage tank T-10 would not assure 7 days of dedicated EDG fuel supply.
The licensee currently maintains tank levels above the TS minimum to satisfy calculated 7 day fuel supply requirements.
The licensee's responses to the team's concerns committed to evaluate and provide necessary corrective action by the fourth quarter of 1992.
This item remains open pending NRC review of the licensee's corrective action (255/91019-22(DRS)).
CPCo Response During the inspection, the NRC noted a number of discrepancies in the calculations and documentation (i.e., FSAR and the technical specifications) associated with the diesel fuel oil storage analyses.
The issue regarding the current Technical Specification 3.7.li limit on diesel generator fuel oil supply was addressed by CPCo in 1989 as a result of the Configuration Control Proj~ct.
We determined that the technical specification limit of 16,000 gallons of diesel fuel oil in T-10 would not support 7 days of diesel generator operation. This is documented in LER 89-005, dated March 3, 1989.
Corrective action for that event included performing a calculation to determine the actual diesel fuel oil storage capacity.
As a result, a technical specifications change request was submitted on November 11, 1989 to increase the diesel fuel oil storage capacity requirement.
We are currently awaiting NRC approval of this technical specification change request.
In the interim, the more restrictive diesel fuel oil storage requirements are being c administratively controlled via Standing Order 54, Section 3.7.li and will serve to insure an adequate supply of diesel fuel oil is maintained.
The remaining issues concerning diesel fuel oil storage analysis are currently being evaluated.
The NRC also identified a weakness in the calculations for the diesel fuel oil storage capacity in that fuel oil consumption rates utilized in the calculations had not been verified by testing.
CPCo had utilized the original diesel generator fuel consumption rate (obtained by test at the factory) in our calculations. Data obtained during the performance of technical specification surveillance test (TSSP) M0-7A, "Emergency Diesel Generators,"
indicated the existing fuel consumption rates were nearly equal the factory test data. A more formal test needs to be performed.
3 The NRC team also identified a weakness concerning the emergency fill lines to the diesel generator day tanks in that they are not included in the maintenance and testing programs.
CPCo will develop a maintenance and testing program commensurate with the significance and probability of the failure of the emergency fill lines.
r Corrective Action The remaining issues concerning diesel fuel oil storage analysis are currently being evaluated and will be completed by the end of 1992.
Recommended corrective actions resulting from this evaluation will be documented and appropriate completion dates will be assigned.
The formal test to determine the diesel generator fuel oil consumption rate as well as the maintenance and testing program for the emergency fill lines to the diesel generator day tanks will be developed by the end of 1992.
Change in Commitment The technical specifications change request described above that was submitted on November 11, 1989 that included a requirement to increase the diesel fuel oil storage capacity has been withdrawn and is documented in the NRC letter dated June 26, 1992.
The withdrawal was due to other changes being necessary in the submittal.
We are continuing to administratively control the more restricted diesel fuel oil storage requirement.
The remaining issues concerning diesel fuel oil storage analysis are currently being evaluated and will not be completed in 1992 as originally scheduled.
The progress and new scheduled completion dates for the specified actions are discussed below.
- 1.
The available on-site fuel oil inventories for diesel fuel oil storage tank T-10, day tanks T-25A/8, and diesel generator belly tanks have been verified but require formal technical review.
The evaluation will be completed in the first quarter of 1993.
- 2.
The formal test to determine fuel oil consumption rate will be developed in the first quarter of 1993 and is scheduled to be performed in May 1993.
- 3.
The results of items 1 and 2 above will be coupled with a detailed diesel generator electric load evaluation to finalize the required fuel oil inventory for the analyzed event.
The final comparison between required fuel oil inventory and the available fuel oil inventory will be completed by October 1993.
The electric load evaluation is presently in progress [and] is expected to be completed by August 1993 to support the final comparison.
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- 4.
The present emergency fill method for the diesel generator day tanks is being re-evaluated to determine the best alternative. Once the best alternative is determined, a functional test will be conducted.
Completion of the functional test is expected by December 1993.
It appears that a fill connection or fill method inside the rooms that contain the diesel generator day tanks will be more dependable and will require less effort to maintain.
Open Item 91019-25 Inspection Report Paragraph 3.3.1.4 - Emergency Diesel Generator Starting The team noted that the EDGs have never been tested to demonstrate their ability to start at minimum hot standby conditions as specified by the manufacturer (i.e., 90°F lube oil and jacket water temperature and 65°F room temperature).
EOG monthly testing does not verify these parameters prior to startup.
The licensee committed to test start the EDGs under these temperature conditions by the end of the next refueling outage.
The possibi7 ity that jacket water and room temperatures could fa 77 below the minimum hot standby conditions was considered significant since these parameters are not under automatic alarm surveillance.
The licensee's response to the team's concern committed to evaluate methods to assure that these temperatures do not fall below design temperatures, including modification or procedure revisions, as required.
This item remains open pending NRC review of the licensee s corrective action (255/91019-25(DRS)).
CPCo Response The diesel generator vendor has supplied information which indicates that the minimum ambient temperature which a diesel generator can be expected to start without starting aids (e.g., warmed lube oil and jacket water) is 50°F.
However, it is not clear that this criteria applies to nuclear plant standby service- (critically timed 1-0 second start).
The system operating procedure for the diesel generators, SOP-22, "Emergency Diesel Generators," states that the lube oil and jacket water temperatures must be maintained above 90°F to insure diesel generator operability. The original purchase specification for the diesel generator states that the minimum expected ambient room temperature would be 60°F.
As indicated in the inspection report, and in our responses to concerns of the EDSFI inspection team, CPCo has not performed a documented test to qualify or validate diesel generator performance at these minimum temperature limits. Also, as indicated in the inspection report, low jacket water temperature and low room temperature are not alarmed parameters.
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5 CPCo believes that frequent testing at the minimum temperatures is not necessary nor prudent in that frequent cold-fast starts have been demonstrated to result in premature diesel generator wear and failure. This issue has been well documented in the industry and specifically in NRC Generic Letter 84-15, "Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability."
However, we will perform a test at the minimum hot standby conditions on a one time basis as a "qualification" test for the diesel generators.
Corrective Action The following actions will be completed to resolve this issue.
- 1.
Perform a one time "qualification" test to demonstrate that an EDG is capable of adequately starting at or below the following conditions:
Cold lube oil temperature ~ 90°F Cold jacket water temperature ~ 90°F Room ambient temperature ~ 60°F CPCo originally committed (in our responses to concerns during the EDSFI inspection) to perform this test by the end of the 1992 refueling outage; however, due to work priorities we were not able to develop and schedule an adequate test to support performance during the 1992 refueling*outage. This testing will now be completed by the end of the 1993 refueling outage.
- 2.
The operator rounds sheet will be revised to include recording of the diesel generator jacket water temperature and the diesel generator room temperature. Action limits and recommended corrective actions will be specified. These revisions will be completed by May 1, 1992.
- 3.
An evaluation will be performed to determine the need to provide an automatic alarm on low jacket water and low room temperature conditions. This evaluation will be completed by December 31, 1992 and any recommended modifications will be scheduled through the plant planning process.
Change in Commitment CPCo committed to the completion of an evaluation to determine the need to provide an automatic alarm on low jacket water and low room temperature conditions. The evaluation will not include lube oil temperature as this is already an alarmed condition.
The evaluation was scheduled for completion by December 31, 1992; however, insufficient time was available to develop acceptance criteria and evaluation methodology for low jacket water and low room temperature conditions.
In addition to the evaluation, a special test procedure T-332, "Emergency Diesel Generator 1-1 Low Temperature Start Test,"
will be developed and performed in the first quarter of 1993 to determine if the diesel generator will start at temperatures below the specified requirements for jacket water temperature, lube oil temperature, and room temperature.
Following completion of the test and evaluation of the results,
a decision will be made regarding the necessity for modifications.
The scheduled completion date of the test and evaluation is September 1993.
Any recommended modifications will be scheduled through the plant planning process.
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Gerald B Slade
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General Manager CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades 6