ML20084M970
| ML20084M970 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 05/02/1984 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 8524N, NUDOCS 8405160238 | |
| Download: ML20084M970 (8) | |
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N Commonwealth Edison
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) O,1e First NTtional Plaza, Chicsgo. lilinois i
C ] Address Reply to: Post Office Box 767
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Chicago, Illinois 60690 e
a May 2, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
Byron Generating Station Units 1 and 2 Seismic Qualification of Equipment NRC Docket Nos. 50-454 and 50-455 Reference (a):
August 10, 1982 letter from T. R. Tramm to H. R. Denton.
Dear Mr. Denton:
The status of seismic qualification of equipment for the Byron /
Braidwood units was reported in reference (a).
It now appears that qualification of a few components may not be complete by the time fuel is loaded at Byron 1.
This letter documents our justifications for interim operation of those components.
Westinghouse OT-2 control switches are used extensively on our control boards.
The seimic qualification of OT-2 switches has been established but, because of minor subcomponent changes, we are unable to assure that the installed switches are seismically identical to the tested switches.
Replacement switches are not expected to be available in time for installation and testing prior to fuel load.
All of the installed safety-related switches will therefore be replaced before the end of the first refueling outage.
Attachment A to this letter contains the justification for interim operation for the OT-2 switches.
Attachment A also contains the justification for interim operation of the W-2 switches which are installed on our control boards.
Current testing schedules indicate that these switches will be fully qualified by July 1, 1984.
Approval for interim operation of W-2 switches is not being sought at this time.
Westinghouse 7300 series instrumentation is used in various NSSS and BOP applications.
The results of recent supplemental seismic testing of this equipment are presently being evaluated.
Test reports are cxpected to be available by July, 1984.
If field changes are necessary, they may not be completed until the first refueling outage.
Attachment A to this letter provides the justification for interim operation (JIO) of the NSSS portion of the 7300 equipment.
A similar JIO for the BOP application will be provided by June 1, 1984.
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H. R. Denton May 2, 1984 The source and intermediate range neutron instrumentation is being modified to alert the reactor operator to reactivity changes associated with postulated boron dilution events.
This equipment has been tested.
It is expected that the test reports will be complete prior to July 1, 1984.
Approval for interim operation is not being sought at this time but the justification for interim operation is contained in Attachment C to this letter.
We are requesting NRC review and approval for interim operation of the OT-2 switches and the NSSS 7300 series instrumentation.
Further requests will be made if it becomes apparent that other components will not be fully qualified by the time of the Byron 1 fuel load.
Please direct further questions regarding this matter to this office.
One signed original and fifteen copies of this letter and the attachments are provided for NRC review.
Very truly yours, jkf.AdW T. R. Tramm Nuclear Licensing Administrator 1m Attachments 8524N a
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1 ie Attachment A Byron Interim Justification Position for the Seismic Qualification of the OT2 and W2 Control Board Switches G
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Background
- 4 Westinghouse has investigated the acceptability of the presently installed OT2 and W2 switches in IE circuits. Similarity of design can be demonstrated for the OT2 switch, but Westinghouse has determined that direct traceability from tested to installed switches is not possible. The testing noted below provides assurance that the switch will operate properly until replacements are obtained. The installed W2 is similar in design to previously tested W2 switches and is currently being seismically qualified. As presented below, sufficient test data exists to establish seismic performance for interim operation until the test program is complete.
Previous Testing OT2 Switch A.
Structural integrity was maintained on tests for the following projects:
1.
Philippines Project at an SSE peak of 4.4 g's 2.
Comanche Peak at an SSE peak of 5.0 g's 3.
Watts Bar at an SSE peak of 8.0 g's 4.
Diablo Canyon at an SSE peak of 32.0 g's and a ZPA of 7.4 B.
Operability was demonstrated on tests for the following projects:
1.
The criteria of less than 10 milliseconds of chatter was met for the Philippine Project at an SSE peak of 4.4 g's 2.
Comanche Peak tests indicated no operating anomolies for an SSE peak of 5.0 g's 3.
Watts Bar tests found no operating anomolies for.an SSE peak of 8.0 g's 4.
The critaria for the Diablo Canyon tests was less than 3 milliseconds of chatter at an SSE peak of 32.0 g's and a ZPA of 7.4.
Two switches were tested. One passed and the other did not meet the criteria.
0096G/BWG/3-21-84
e' U2 Switch A.
Structural integrity was maintained on the following tests:
1.
Westinghouse Switchgear Division at an SSE peak of 6.2 g's and a ZPA of 3.2 g's 2.
Watts Bar at an SSE peak of 8.0 g's 3.
Diablo Canyon at an SSE peak of 32.0 g's and a ZPA of 7.4 B.
Operability was demonstrated through the following tests:
1.
Westinghouse Switchgear Division reported no operating anomolies at an SSE peak of 6.2 g's and a ZPA of 3.2 g's 2.
Watts Bar tests indicating no operating anomolies for an SSE peak of 8.0 g's 3.
The criteria for the Diablo Canyon tests was less than 3 milliseconds of chatter at an SSE peak of 32.0 g's and a ZPA of 7.4.
Of the two switches tested, one met the criteria and the other did not.
Conclusions W2 and OT2 Switches The Byron seismic criteria is for an SSE of 5.2 g's and a ZPA of 1.0 g maximum. Tests were conducted near or in excess of this level. Based on the results there is sufficient confidence to assume structural integrity and operability will be maintained in a seismic event.
Actions The OT2 switches in the Main Control Board will be replaced with base line controlled / fully qualified switches when available.
The W2 switchds from the liain Control Board are presently under going testing and are expected to be qualified prior to core load.
i 0096G/BWG/3-21-84
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i ATTACHMENT B Byron Interim Justification' Position for the r
i Seismic and Environmental Qualification of the 7300 Process Protection System (ESE-13)
Westinghouse is presently evaluating the results of the
. supplemental-abnormal environment and. seismic testing recently completed.
l This supplemental testing was performed at several seismic. levels, the last of which would upgrade the_ seismic qualification of the.7300 process protection system to a level above that required for Byron and to perform
' initial testing of-some recently developed cards.
With_the exception of the NPC (Potentiometer), NRC (Relay), NCH (Function' Gene'rator)'and the
_ NSC (Conver'cer) cards seismic qualification. for Byron is documented by -
i the:following: reports:
E13A, " Process Protection (Seismic Testing)";
7 E138, " Process-Protection System (Environmental and Supplemental Seismic Testing)".
During this' supplemental ~ testing, the.following was observedt j
The NRC card demonstrated proper operation.during the tests.
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b.
The NPC, NCH,.and NSC cards exhibited errors which could result'in L
- minor changes in system accuracy.-
The NPC and NCH: cards ~have potentiometers which demonstrated small shifts during the seismic 1..
j, testing.
It is expected that the resultant system error will be less1 than'O.5% based on a maximum _ pot shift of 1%.
.The :NSC card:and ~
1-cabinet power supply' exhibited changes-due to input voltage.
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variations that exceeded-specification by.less than 0.5%.
These errors are presently'under evaluation by. Westinghouse in order to determine the exact effect onfthe system, but initial. evaluation
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f indicates thatjmargins are available to absorb-these_inacurracies.-
Although. tested previously, the NTC (Temperature! Channel Test)-
card exhibited contact bounce during this recentztesting.
The_results
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have been: evaluated'andJreported:by Westinghouse 1to the NRC on! June 1, 1983.
' Commonwealth. Edison alsoireported,this-pursant-to 10.CFR 50.55(e)
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in a letter dated August 9, '1983, from-~_T.
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Tramm.to J.- G. Keppler.:
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Byron has this NTC card:in:the-Overtemperature and Overpower deltaLT' channels.
This intermittent signal 1may cause saturation 1ofl downstream RTD amplifierL(NRA) cards and could. possibly: prevent-a' trip fromfoccuring i
1 on demand.,Until a permanent resolution'is~ prepared, Field ChangeL Notices have beentissued'which_will pro' vide aJmethod of1bypassingLthese:
relays'when in normal 1 operation.' -SinceJthesecrelays areEonly'used to ease i
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- periodicLtesting of the channels, this interim modificationfwill'not-Einterfere with plant-operation;-
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J 0 The 7300 Process Protection System performance has been demon-strated to be acceptable for Byron by previous seismic testing.
Anomalies which occurred during recent tests are being resolved and corrective actions will be taken as necessary based on the results of the Westinghouse evaluation.
All testing, including preparation of test reports, is scheduled for completion by July, 1984.
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ATTACHMENT C Byron Interim Justification Position for the Seismic and Environmental Qualification of the Baron Dilution Fix (ESE-47)
The Boron Dilution Protection System equipment, which consists of the Source and Intermediate Range Drawers, Source / Intermediate Range Detector and Source Range Pre-Amplifier, has completed seismic and envi-ronmental testing.
The seismic testing was successfully completed for all equipment.- Abnormal environmental testing revealed that the log-current amplifier (located in the Intermediate Range drawer) exhibited errors which exceeded the acceptance criteria.
For Byron this system is located in the control room which.has Class IE HVAC and will not experience an abnormal environment.
All other eoulpment successfully passed the environmental tests.
Although-the Source-Range Pre-amplifier successfully passed the seismic and environmental tests, it was noticed to be noise susceptible.
during system verification testing which leads to an operational concern.
For this reason, a new pre-amplifier (Model MK II) was designed.
Byron.will operate with this redesigned part.
Seismic testing of the pre-amplifier was completed dbr'ing the first quarter of 1984.
Results of the tests were sati'sfactory, however, during the test the triaxial connector failed.
Investigation revealed that the connector had been redesigned by the manufacturer without informingfWestinghouse.
The older' style connector was installed and subsequent' seismic test 3esults were satisfactory.
Since Byron pre-amplifiers presently have the new' style connectors. installed a Field Change Notice will be: issued to replace the connectors prior to the scheduled fuel load date.
Upon completion of te' sting of the MK II pre-amplifier,. a draf t EQDP-ESE-478 report titled " Boron Dilution Fix (Source and Intermediate Range Drawers and Source Range Pre-Amplifier)" and an EQTR-E47C report titled "NIS? Console, Source and-Intermediate Range' Drawers, Source Range Pre-Amplifier Dox (Environmental Testing)" will be issued.
LAll t'esting,-including reports,, will be complete in June 1984.
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