IR 05000271/1989014
| ML20247M883 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 09/18/1989 |
| From: | Anderson C, Della Greca A NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | |
| Shared Package | |
| ML20247M868 | List: |
| References | |
| 50-271-89-14, IEIN-84-44, IEIN-88-081, IEIN-88-81, NUDOCS 8909260075 | |
| Download: ML20247M883 (8) | |
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.I U.S. NUCLEAR REGULATORY COMMISSION
REGION I
i Report No.
50-?71/89-14.
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Docket No'.
50-271
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License No.
DRP-28-
'1 Licensee:
Vermont Yankee Nuclear Power Corporation.
Brattleboro, Vermont- 05301 Facility Name: Vermont Yankee Nuclear Power Station Inspection At: Vernon, Vermont Inspection Conducted: August 7-11, 1989 OOb Inspectors:
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r, FSS, EB date
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A. L. Della Greca, Reaf6r Approved by:
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C"J. Anderson, Chief; Plant J., temsdection, EB
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- Inspection Summary:
Inspection on August 7-n, 1989 Inspection Report No. 50-271/89-14 Areis Inspected: -Announced inspection by regional personnel to review the status of previously identified items and to-determine the adequacy of the licensee's actions to resolve them.
Results: The inspector determined that the licensee has satisfactorily responded to eight open items. One item remains open pending the licensee's reevaluation
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and' updating of its calculations for Thomas and Betts qualified life.
No new violation was identified.
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8909260075 890919 FDR ADOCK 05000271 Q
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DETAILS 1.0 Persons Contacted
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1.1 Vermont Yankee Nuclear Power Corporation
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- R. Wanczyk, Operations Superintendent S. Jefferson, Assistant to Plant Manager
- M. Mete 11, Engineering Support Supervisor
- D. Phillips, Senior Electrical Engineer i
I 1.2 Yankee Atomic Electric Company
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P. Johnson, Lead Electrical Engineer M. Saniuk, EQ Cognizant Engineer
- R. Grippardi, Quality Assurance Supervisor
- Denotes personnel present at the exit meeting of August 11, 1989.
2.0 Purpose The purpose of the inspection was to review the status of previously identified' items and to determine the adequacy of the licensee' corrective actions in resolving each issue.
3.0 Status of Previously Identified Items 3.1 (Closed) Violation (Item No. 50-271/87-19-01) pertaining to the lack of qualification documentation for the Cerro EP/Hypalon Cables.
At the time of the original inspection, review of QDR 6.15 revealed that licensee was relying on Rockbestos test report QR No.1804A to support the environmental qualification of the Cerro cable. However, this report was considered invalid by the NRC because of the qualifica-tion deficiencies described in IE Information Notice 84-44.
In response to the Notice of Violation, the licensee obtained a test report from Franklin Research and used this to support the qualification of the Cerro cable. This report was added to the qualification package, QDR 6.15 The licensee's resolution is acceptable and this item is closed.
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3.2 (Closed) Violation (Item No. 50-271/87-19-02) regarding the lack of
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qualification documents for the Rome (Cyprus) XLPE/PVC cables.
Review of QDR 6.14 revealed that the licensee based the qualification of the Rome cable upon the Franklin Research test report No. F-C 3016.
Since the peak temperature used in the Franklin test did not envelop the plant required temperature, the licensee attempted to support qualification by using other tests for cables with similar insulating l
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materials. The documentation package, however, contained no analysis to support similarity between the Rome cables installed at Vermont Yankee and the cables manufactured by other companies and used as basis for qualification In response to the NRC finding, the licensee attempted to obtain from the various manufacturers the material information required to perform the similarity analysis. However, the licensee determined that the manufacturers were reluctant to provide such data, since it was of a proprietary nature. As a consequence, the licensee decided to test naturally aged cable samples taken from the plant. The test performed by the licensee successfully demonstrated the capability of the Rome cable to withstand the Vermont Yankee calculated accident environment.
The test report and an appropriate aging analysis were added to the qualification package.
The documentation provided adequately supports qualification of the Rome cables. This item is closed.
3.3 _(Closed) Violation (Item 50-271/87-19-03) relative to the lack of qualification for the Lewis PE/PVC instrument cables.
Evaluation of tne qualification package for the Lewis cables revealed that the environmental qualification was based upon a test report for PE/PVC cable and an Ebasco specification.
Since the test report did not identify the cable manufacturer, the licensee was informed that it could not use it as a basis for qualifying the Lewis cable.
Following the October 1987 inspection, the licensee was able to obtain from Wyle Laboratories a test report for a Simplex PE/PVC cables. However, because of an unscheduled outage, the licensee considered it more prudent to replace the Lewis cables with qualified Rockbestos cables, type Firewall III. The qualification file for the Levis cable was subsequently cancelled. To show that the modifica-tion had been completed, the licensee provided a copy of the revised qualification package for the Rockbestos cable, QDR No.6.4-2, as well as copies of the Vermont Yankee modification request. The installa-tion was further verified during a plant walkdown.
Replacement of the Lewis cables with qualified Rockbestos cables adequately resolves the issue and this item is closed.
3.4 (Closed) Violation (Item No. 50-271/87-19-04) pertaining to the inadequate qualification documentation for the 3M splices.
During the original inspection the NRC determined that the licensee based the qualification of its 3M splices on their similarity to Okonite splices constructed with T-95 and T-35 tapes. The thickness of the 3M and of the qualified Okonite tapes are different.
In addition, the overlapping requirements were not addressed by the qualification file. Therefore, the similarity between the two tapes was not clearly established.
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An evaluation of the splice application performed'by the licensee indicated that the splices were qualifiable based upon data obtained from Wyle Laboratories. However,. subsequent to the inspection, because of an unanticipated plant shutdown, the licensee considered more prudent and conservative to replace the four splices involved with qualified Raychem splices.
The installation of the Raychem splices could not be independently verified because the termination boxes could not be open without declaring the associated motor operated valves. inoperable.
However, the licensee provided adequate documentation to ensure that the installation of the splices had taken place.
l The licensee's resolution of the issue is adequate and the item is closed 3.5 (Closed) Violation (Item No. 87-19-05) pertaining to the insulation resir.tance of the General Electric EB-5 terminal blocks.
At the time of the finding, the NRC inspector noticed that the EG-5 terminal blocks were potentially subject to a post-accident steat.
environment and that the Limitorque test report, on which qualification was based, identified a 500 Ohm insulation resistance after four days of exposure to that environment.
The inspector became concerned that leakage currents resulting from the low insulation resistance measured could result in erroneous signals from the transmitters to the control and indicating instruments.
Following the October 1987 inspection, the licensee was able to obtain from General Electric a report of a test performed by Wyle Laboratories with EB-5 and EB-25 terminal blocks.
In addition, the licensee performed an evaluation of the circuits which utilized the EB-5 terminal blocks. The licensee, thus, determined that the EB-5 terminal blocks were only used in conjunction with the scram solenoid valves, whereas in the Rosemount transmitter loops ES-15 type terminal blocks were used. On the basis of its findin5s the licensee was able to show, by analysis, that the leakage current resulting from a low insulation resistance would not impair the safe operation of the scram solenoid valves. The reason for its conclusion is that the scram solenoid valves operate in the fail-safe mode. Therefore, in the remote event that the leakage current became too high, the end result would be the blowing of the protective fuses with consequent scramming of the reactor.
The analysis performed by the licensee resolves the EB-5 issue and the item is close _ - _ _ -
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3.6. (Closed) Violation (Item No.50-271/87-19-06) pertaining to inadequate qualification documentation for the Dings brakes in Limitorque valve.
actuators.
During the original review, the inspector determined that the qualifica-tion package for the Limitorque actuators did not contain adequate documentation to support qualification of the Dings brakes.
Specifically, the qualification of the brakes was supported by a Certificate of Compliance which. stated that the brake material were equivalent or superior to those included in Limitorque Qualification Report 600198.
Since the test addressed in this' report did not include radiation aging, the certificate also stated that the capability of the brake to withstabe radiation could be supported by Qualification Report No.
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600376A. An analysis showing similarity between the materials tested
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in this latter report and those found in the Dings brakes.had not_
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Following the inspection, the licensee performed the similarity analysis and provided the radiation thre Sold of the materials. The analysis was added to the qualification report.
The analysis provided by the licensee adequately addresses the radiation qualification of the Dings brakes.
This item is closed.
3.7 (Open) Unresolved (Item No. 50-271/87-19-07) regarding the lack of qualification of wire connectors in Limitorque actuators.
During the October 1987 inspection, while conducting the physical inspection of several Limitorque actuators, the inspectors found that three motors terminations contained unidentified wire connectors and that the Limitorque qualification file contained no documentation to support the environmental qualification of these connectors.
Following the October 1987 inspection, the licensee provided additional data to address qualification. However, the data furnished did not support the identification of the wire connectors, nor did it ensure that the installed configurations were the seme as l
the tested configuration.
In response to the first concern, the licensee determined that the connectors were Thomas and Betts RB-4 or RC-6 wire joints and that the material was Zytel 101. The determina-tion was based upon Limitorque statement that the Thonias and Betts connectors were the only one used in conjunction with dual voltage motors. The licensee based qualification of the connectors for Vermont Yankee's post-accident environment Limitorque's Test Report No. B0003.
In addition, since the report does not clearly show that
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the connectors underwent thermal aging prior to the accident test,
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the licensee addressed thermal aging in an analysis which also calcu-lates the connectors' qualified life on the basis of the Illinois Power test addressed by Information Notice 88-81 and an activation energy of 1.17 for the Zytel 101.
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In response to the second concern, the licensee determined that Limitorque had developed no documentation pertaining to production and tested configuration with respect to the connectors. Therefore, the licensee could not assure the similarity between the installed and tested configurations. The licensee assumed the least conserva-tive installation, i.e., terminals in contact with the grounded enclosure and justified qualification of the assumed installation using the same test mentioned above. According to the licensee, this test was performed with connectors in intimate contact with the grounded switch component. The licensee's claim is also implied by statements contained in Information Notice 88-81.
The report for the test performed by Illinois Power was not available in the qualification package.
However, it is known from the IE Not1ce that the connector passed the qualification testing after thermal i
aging for an equivalent of eight years at 125 degrees Fahrenheit but failed after an equivalent aging of eight years at 150 degrees.
Since the Illinois Power tasting clearly established age related failure of the material the licensee was asked why a more conservative activation energy had not been used.n its calculation. The qualifica-tion package reports activation energies of 1.17 eV for dielectric strength, 0.86 eV for tensile strength and 0.83 eV for tensile strength
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with impact.
The licensee replied that 1.17 eV was the activation energy generally used oy the industry. The licensee also felt that tensile strength was not an applicable characteristic. Although tensile strength may not be applicable, the use of 1.17 eV activation energy to project the connectors' quclified life is questionable since the cracking experienced in the failed Illinois Power test may not be detectable by dielectric strength. The qualified life issue is not a safety concern a the present time since the use of the Illinois Power results with a more reasonable activation energy, will yield a service life in excess of 20 years.
This item remains open pending (1) further justification by the licensee as to the reasonableness of the activation energy used by its calculation and (2) addition of the Illinois Power report (extensively used for the qualification of the connector) to the qualification package.
3.8 (Closed) Unresolved (Item No. 50-271/87-19-08) pertaining to the environmental qualification of Limitorque motor wire leads.
During the October 1987 inspection, while conducting the physical inspection of some safety related valves, the NRC inspector observed some motor leads with two distinct types of insulation, one type colored gray and another colored red. The two types of insulation could not be immediately traced to a qualified *.ype.
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Following the-October 1987 inspection, the licensee obtained a letter from Limitorque' identifying the insulation _as Exar, a chemically cross linked polyethylene, qualified by its Test. Report No. B0003.
The letter also stated that Exar comes both in grey and red coloration.
The documentation provided by the licensee is acceptable and the item is closed.
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3.9 -(Closed) Unresolved (Item No. 50-271/87-17-09) regarding the Rosemount-transmitters fourid with loose covers.
During the October 1987 intpection, while conducting the physical inspection of the plant transmitters, the inspector observed a Rosemount. transmitter with an improperly torqued right side cover.
The licensee explained that the particular transmitter was not subject to a steam environment and that there was ne requirement for torquing for such application. Nonetheless, the licensee took steps to check all the transndtters covers to ensure that the were properly torqued.
Further inspection by the iicensee revagled the existence of seven more loose covers. The licensee torqued each cover and provided adequate justification for the finding.
In addition,-the licensee revised the procedure currently used'for the surveillance, and pre-ventive maintenance of safety related equipment, No. AP 0310, to require that the EQ file be reviewed for EQ requirements each time a cof re is tested.
Physical inspection of all transmitters during this inspection identified no loose covers. This item is closed.
4.0 Review of GE EB-25 Terminal Block Qualification Document While reviewing the licensee's response to violation item 87-19-05, paragraph 3.5, above, the inspector determined that the Rosemount transmitter loops utilized General Electric type EB-25 terminal blocks.
Since these terminal blocks are similar to the Model EB-5 blocks, which were the subject of the previous NRC finding, the inspector reviewed QDR No.17.4A and Wyle's test results to ensure that_ the original concerns regarding leakage current and instrument loop accuracy had been resolved.
Evaluation of the analysis provided on Page A-5 of the QDR shows that the licensee has addressed-leakage current. However, the analysis also appears to indicate that the licensee:
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Did not use the lowest insulation resistance measured by the Wyle test.
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Improperly calculated loop error by comparing the measured' leakage current to the mean valve (50%) of the instrument loop current.
Since the same leakage current can greatly affect set pointsuat the lower end of the scale, the inspector discussed the concern with the licensee.
The inspector, thus, determined that the licensee's set point calculations take into account the error resulting from reduced terminal block insulation resistance and that the amount of error included is a function of the temperature experienced by the terminal blocks. The method used by the licensee to address. leakage current is acceptable.
However, the analysis on page A5 of the QDR should be revised to reflect the method used.
In addition, the analysis should justify the non-applicability of the insulation resistance measurements observed with terminal boards used with the low voltage relay, power supply and temperature switch circuits.
This item is unresolved pending appropriate revision of the QDR.
(50-271/89-14-01)
5.0 Physical Inspection A walkdown of the plant was conducted to verify the installation of the Rockbestos cables and to check the kesemount transmitters. No violations -
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6.0 Unresolved Items Unresolved items are matters about which additional information is necessary in order to determine whether it is acceptable or a violation.
Unresolved item is discussed in piragraph 4.0.
7.0 Exit Meeting l
The inspectors met with the licensee's personnel denoted in paragraph I of this report at the conclusion of the inspection period on August 11, 1989.
At that time the scope of the inspection and the inspection's results were
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summarized. At no time during the inspection was written material given to the licensee.
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