ML20136D060
| ML20136D060 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 11/15/1985 |
| From: | VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| Shared Package | |
| ML20136D042 | List: |
| References | |
| NUDOCS 8511210216 | |
| Download: ML20136D060 (7) | |
Text
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E ATTACHMENT 1 PROPOSED TECHNICAL SPECIFICATION CHANGE FOR UNIT 1 i
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TABLE 3.3-7 i
SEISMIC MONITORING INSTRUMENTATION MINIMUM MEASUREMENT INSTRUMENTS INSTRUMENTS AND SENSOR LOCATIONS RANGE OPERABLE 1.
Triaxial Time-History Accelerographs a.
Containment Mat
- O - 1.0 g 1
b.
Containment Operating Level
- O - 1.0 g i
2.
Triaxial Peak Accelerographs a.
RHR Heat Exchanger 0 - 5.0 g i
b.
Safety Injection Pipe 0 - 5.0 g I
c.
Component Cooling Heat Exchanger 0 - 5.0 g 1
3.
Triaxial Seismic Switches a.
Containment Mat
- NA NA 4.
Triaxial Response-Spectrum Recorders a.
Containment Mac*
1 - 30 Hz 1
s b.
Auxiliary Bu11dite Mat 1 - 30 Hz 1
c.
RHR Pipe Support 1 - 30 Hz 1
d.
Component Cooling Heat Exchanger 1 - 30 Hz 1
Support
- With reactor control room indication 0-NORTH ANNA - UNIT 1 3/4 3-41 l
TABLE 4.3-4 SEISMIC MONITORING INSTRUMENTATION SURVEILLANCE REQUIREMENTS CHANNEL CHANNEL CHANNEL FUNCTIONAL INSTRUMENTS AND SENSOR LOCATIONS CHECK CALIBRATION TEST 1.
Triaxial Time-History Accelerographs a.
Containment Mat M*
R SA*
b.
Containment Operating Level M*
R SA*
2.
Triaxial Peak Accelerographs a.
RHR Heat Exchanger NA R
NA b.
Safety Injection Pipe NA R
NA c.
Component Cooling Heat Exchanger NA R
NA 3.
Triaxial Seismic Switches a.
Containment Mat NA R
SA 4.
Triaxial Response-Spectrum Recorders a.
Containment Mat M**
R NA b.
Auxiliary Building Mat M***
R NA c.
RHR Pipe Support NA R
NA d.-
Component Cooling Heat Exchanger Support M***
R NA
- Except seismic trigger
- Testing will include annunciator circuit only.
- Testing will only include a visual inspection to detect for signs of obvious physical damage NORTH ANNA - UNIT 1 3/4 3-42
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AITACHMENT 2 SAFETY EVALUATION s
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SAFETY EVALUATION The current.
surveillance requirements for seismic monitoring instrumentation require semi-annual channel functional tests for the four (4) triaxial response recorders listed in Technical Specifications Table 4.3-4.
All of these recorders are passive devices. Guidance provided by ANSI /ANS Standard 2.2, 1978 and the recorder manufacturer, Engdahl Enterprises, indicate that these recorders do not require a channel functional test since they are passive devices. Table 1 of ANSI /ANS Standard 2.2 on frequency of maintenance specifically recommends that no channel functional test be performed for self-contained, passive instruments. Beyond this guidance, we have experienced that the physical act of functional testing the containment mat recorder during plant
. operations may result in damage to the device. The proposed change will revise the specifications to be consistent with current guidance and the manufacturer's recommendations.
The containment mat triaxial response recorder is the only one of these passive devices with a remote indication (annunciator). The recorder itself is primarily a mechanical device, consisting of an event recording plate and a scriber. During a seismic event, the scriber will record
-scriber shank deflection by etching the motion on the plate. This plate would subsequently be removed for post-event analysis. The associated annunciator is used to alert the operator that the device has recorded scriber motion. Within,the recorder, the annunciator circuitry consists merely of alarm contacts which interface with the scriber should significant motion occur.
Surveillance requirements per the current Technical Specifications require semi-annual functional testing of all the triaxial response recorders. For these passive devices, functional testing is impractical, being limited to confirming that the recording plate is properly located, the scriber shank deflects,- and the annunciator, if provided, will properly function electrically.
In the case of the containment mat recorder, this testing may require' containment entry at power with the commensurate protective clothing, self-contained breathing apparatus and limited access time (ALARA concerns). Under these conditions, testing can easily result in damage to the equipment, such as bent scriber shank or bent annunciator contacts.
We have actually experienced corrosion problems and broken contacts attributed to opening the self-contained device and testing under such adverse conditions. We postulate that the occurrence of corrosion within the recorder was due to the introduction of the high humidity environment into the internals of the device during functional testing.
It should be noted that triaxial response-spectrum recorders are not the only seismic instrumentation provided in the plant.
Triaxial accelerographs and seismic switches are provided as noted in Table 3.3-7.
The proposed changes to Technical Specification 3.3.3.3 include deletion of the semi-annual channel function test for triaxial response-spectrum recorders.
This is consistent with ANSI /ANS Standard 2.2 for passive devices as well as the recommendations of the manufacturer. This change does not affect the refueling channel calibration requirement, which remains unchanged.
The proposed changes also include a monthly visual inspection of
" accessible" recorders for signs of obvious physical damage and a monthly annunciator check of the containment mat triaxial recorder. Consistent with ANSI /ANS 2.2, which defines " accessible" as " instruments or sensors whose locations permit ready access during plant operation", monthly visual inspections will be limited to those recorders located outside of containment. The monthly annunciator check of the containment triaxial recorder is consistent with ANSI /ANS 2.2' requirements for channel checks of active devices.
Active devices are defined by the Standard as
" instruments requiring a power source to sense motion or to record data".
As such, only the annunciator of the containment mat triaxial recorder is being treated as an " active" device.
An additional change is proposed to Technical Specifications Table 3.3-7, Item 4.
The listed instrument measurement range for the triaxial response-spectrum recorders is Og - 34g. The correct range should be 1.0 Hz - 30 Hz.
This is consistent with the ANSI /ANS Standard 2.2, 1978 and with Section 3.7.4.5 of the North Anna UFSAR. This proposed change is administrative to correct an error in the existing specifications.
50.59 and Significant Hazards Review Pursuant to 10 0FR 50.59, we have reviewed the proposed Technical Specification changes and have concluded that no unreviewed safety question exists:
(1) the possibility of occurrence or the consequence of a malfunction of the equipment previously evaluated in the UFSAR is not increased, (ii) the possibility of a different type of accident other than discussed in the UFSAR has not been created, and (iii) the margin of safety as described in the BASES Section of any part of Technical Specifications has not been reduced. The proposed changes have no effect on plant design, operation, or safety.
The purpose of the subject instrumentation is to record information for post-event determination to assess if design vibratory ground motions have been exceeded.
Furthermore, the proposed changes do not alter the operability requirements of the triaxial recorders, but rather are administrative in nature, to reflect actual instrument capabilities and test requirements.
The proposed change does not pose a significant hazards consideration as defined in 10 CFR 50.92. The Commission has provided examples (48FR14870) of changes that constitute no significant hazards consideration: example (i) consists of purely administrative changes and example (vii) includes changes made to conform with regulations where the license change results in very minor changes to facility operations clearly in keeping with the regulations.
The proposed change is similar to example (i) in that it corrects an incorrectly specified frequency range for the triaxial response-spectrum recorders. The correct range is specified in the North Anna UFSAR and is also consistent with applicable ANSI standards. Therefore, this portion of the change is administrative.
The proposed change is also similar to example (vii) in that the change to delete semi-annual functional testing of the passive recorders and add a monthly. annunciator check, as applicable, is made to conform with the guidance for testing specified in ANSI /ANS 2.2.
Likewise, the changes to add monthly visual inspections of accessible recorders is consistent with present NRC and ANSI /ANS 2.2 interpretations for surveillance requirements.
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