ML16342C950
| ML16342C950 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 02/04/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML16342C949 | List: |
| References | |
| RTR-REGGD-01.097, RTR-REGGD-1.097 NUDOCS 9506190327 | |
| Download: ML16342C950 (6) | |
Text
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+~**4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055&4001 SAFETY V LU 0
Enclosure H
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GUIDE 9
ACIFIC GAS ND EL C
C CO I BLO CANYON UCL OW U I S ND DOCKET NOS, 50-5 ND 50-3 3
- 1. 0 INTRODUCTION In a submittal, dated February 17, 1993, the licensee documented deviations from the guidance in R.G. 1.97, that had not previously been identified.
Resolution of these deviations is discussed below.
- 2. 0 EVALUATION The staff reviewed the licensee's February 17, 1993 submittal which identified deviations and exceptions with regard to:
(1) meteorological variables, (2) containment
- pressure, (3) accumulator isolation valve position, (4) pressurizer level, (5)
RCS hot and cold leg temperature, (6) separation of redundant instrumentation, (7) ANSI/ANS Standard 4.5-1980 and (8) quality assurance.
These issues are discussed below.
(1)
R.G. 1.97 recommends that meteorological variables (wind direction, wind
- speed, and estimation of atmospheric stability) be monitored by Category 3 instrumentation.
The licensee uses the plant process computer as the indicating device.
The plant process computer meets 'Category 2.~
criteria.
The use of instrumentation that meets or exceeds the criteria in R.G. 1.97 is acceptable.
Therefore, the use of the plant process computer to monitor meteorological variables is acceptable.
(2)
R.G. 1.97 recommends Category 1 containment pressure instrumentation with a range of -5 psig to 3 times design pressure.
The licensee has provided Category 1 display and recording instrumentation that displays from -5 psig to 200 psig and records from 0 psig to 200 psig.
The licensee has also provided Category 2'Irecording instrumentation with a range from -5 psig to 5 psig.
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Category I recording is provided for the positive pressure range extending well above the maximum specified by R.G. 1.97.
This positive pressure range would be the primary range of interest during and following an accident because the effect of the accident would be to incr ease containment pressure.
Therefore, the existing containment pressure instrumentation is acceptable.
R.G. 1.97 recommends Category 2 accumulator isolation valve position indication.
The licensee has provided Category 3 accumulator isolation valve position switches, but according to the licensee's technical specifications, power is removed from these valves, and therefore, they are open and de-energized when the reactor is critical.
Based. on the licensee's justification that these valves are open and cannot change position during or following an accident,
'the staff considers the existing accumulator isolation valve position indication acceptable.
R.G.
1.97 recommends Category I pressurizer level monitoring instrumentation.
The licensee stated that a single Category 2,
- recorder, isolated from Category I instrumentation, is used to record all three channels of pressurizer level.
The licensee further stated that the. three channels are also recorded by computer.
The use of Category 2'ecorders and computers, properly isolated. from Category I instrumentation, is acceptable for the recording of Category I information.
Therefore, the licensee's pressurizer level monitoring instrumentation is acceptable.
R.G.
1.97 recommends Category I RCS hot and cold leg temperature monitoring instrumentation.
The licensee has Category I RCS hot and cold leg temperature monitoring instrumentation that is in conformance with R.G. 1.97.
In addition, a
RCS temperature selector switch has been provided to select either loop I RCS hot leg temperature, of loop I RCS cold leg temperature for display on the PDS panel (a dedicated remote shutdown panel).
The selector switch and the indicator on the PDS panel meet the, Category 2 criteria.
When the switch is not set to either the hot or cold leg position it is set to the "calibrate" position.
The use of this switch is controlled by technical specification and is only used for temperature indication during remote shutdown from outside the control room.
In the "calibrate" position the switch. contacts isolate the Category I portion of the circuit from the Category 2 instrumentation.
We have reviewed the isolation provided by this selector switch and have determined that this switch provides adequate isolation of the Category I portion of the circuit from the Category 2 i'nstrumentation.
Therefore, the existing RCS hot and cold leg temperature instrumentation is acceptable.
R.G.
1.97 recommends redundant channels. for Category I instrumentation.
Redundancy should include electrical independence and physical separation.
Physical separation is required between redundant channels
and between a Category 1 channel ad other equipment not classified important to safety, up to and including isolation devices.
The existing physical separation between channels at the plant meets the design criteria that were in effect at the time of isolation.
- However, since the original design predates the separation requirements of R.G.
1.75, not all Category 1 channels have complete physical separation.
The licensee acknowledged that the control room instrumentation does not meet the physical separation criteria of R.G.
1.75 between channels.
The licensee stated that future modification to Category 1
instrumentation will conform with R.G.
1.75 guidelines where feasible.
Mith the licensee's commitment to review the feasibility of conformance with the R.G.
1.75 guidelines for future modifications, the staff finds the licensee's position on separation of Category 1 instrumentation channels acceptable.
(7)
R.G.
1.97 references ANSI/ANS Standard 4.5-1980 regarding the criteria for post-accident monitoring instrumentation.
The licensee has provided clarification of the application of the ANSI standard to the plant and has committed to the design criteria recommended in R.G.
1.97 for post-accident monitoring instrumentation.
The staff has reviewed this instrumentation and found the deviations from the R.G.
1.97 criteria acceptable.
(8)
The licensee has provided clarification on their application of the quality assurance required by R.G.
1.97 on electrical sub-components.
The staff has reviewed the licensee's clarification and found the deviations from R.G. 1.97 acceptable.
- 3. 0 CONCLUSION Based on our review of the licensee's submittal, the staff concludes that the licensee has provided appropriate justification for deviations from and exceptions to R.G. 1.97, Revision 3, for instrumentation that monitors (1) meteorological variables, (2) containment
- pressure, (3) accumulator isolation valve position, (4) pressurizer level, and (5)
RCS hot and cold leg temperature and, therefore, we find this instrumentation acceptable.
In addition, the staff concludes that the licensee's deviations from the separation criteria, and quality assurance are also acceptable.
Principal Contributor:
B. Marcus Date:
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