ML20057A808
| ML20057A808 | |
| Person / Time | |
|---|---|
| Issue date: | 09/08/1993 |
| From: | Wermiel J Office of Nuclear Reactor Regulation |
| To: | Rockwell D GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 9309150353 | |
| Download: ML20057A808 (4) | |
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.9:pt ember S, 194 Donald Rockwell General Electric Company 175 Curtner Avenue Mail Code 482 l
San Jose, CA 95125 l
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SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION IN SUPPORT OF THE STAFF REVIEW 0F
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TOPICAL REPORT NEDC-32160p " CALIBRATION INTERVAL EXTENSION" l
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Dear Mr. Rockwell,
l Enclosed is a list of general questions and request for clarification for the referenced topical report. The staff has concluded that the requested f
information will be necessary to complete the review. When you have resolved these questions and developed a response, I would like to arrange a meeting to j
discuss this topical report.
I Or1Rinal signed by:
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Jared S. Wermiel Chief i
Instrumentation and Controls Branch Division of Reactor Controls and Human factors
Enclosure:
List of General Questions i
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DISCUSSION l
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i The initial review of the information provided in the topical report has been l
c ompl et ed.
As a result of the initial review, several areas have been identified where adequate information was not included to justify the proposed j
increase in calibration frequency.
In order to complete the review of Topical Report NED-32160P, the following additional information is requested:
1.
Please provided justification for including calibration data in the study for intervals of less than 18 months.
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2.
Please provide a list of criteria used for obtaining calibration data for the study.
i 3.
A Channel Calibration encompasses the entire channel including the i
sensor and alarm and/or trip functions.
Therefore, " Drift Error" is a combination of the instrument drift of all components in the instrument channel, in the case of a " switch" type device, the term l
" data point" in Appendix E would be the point at which the switch l
actuated when tested.
In the case of a trip unit with a 16ma dc span receiving a signal from a transmitter, what does the term
- data point" represent?
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4.
On page 1-1 of the report it is stated, " Failures are usually
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detected by operator observations or channel checks, but can also be detected when performing channel or logic system functional tests as justification for increased calibration intervals."
In the Appendix l
D definition for " Logic System functional Test " the sensor is i
removed from the required sccpe of t' test.
The sensor is the l
largest drift contributor in the chanaci.
Does omission of the sensor in the Logic Functional Test change this justification?
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5.
Is the Appandix D definition change for " Logic System functional Test
- a proposed Technical Specification change?
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i 6.
Data in Section 5, Appendix E does not include engineering units for j
most of the data.
Please provide engineering units for span, accuracy, calibration error, drift, drift temperature error, etc.
I 7.
The reviewer was unable to determine the actual source of data i
included in the study.
For example:
l Is all data used in the study obtained from 18 month Technical Specification channel calibration records?
I Is all data included in the study obtained by simulating the process variable at the senser and recording the actual trip l
value at the initiating device?
i Are accuracy values, calibration error values, drift values, and drift temperature error values included in the topical i
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, report based on all components in an instrument channel being tested as a channel, or on individual trip actuation devices only?
8.
Please provide data from channel calibration records used in the study which indicates how many times the instrument channel exceeded its acceptable limits for an 18 month interval.
9.
The reviewer considered some of the data in Section 5 of the topical l
report to be questionable.
The following are examples which require justification l
Section 5.2 Barksdale Pressure Switches:
Why is calibration error zero for 2750 rpan?
i Why does " drift" improve significantly with an i
increase in span from 2750 to 3040?
Why does " accuracy" improve from 55 to 16 with a span change from 2750 to 3040) i Is all data recorded for a specific model of instrument, or is data recorded for different models of Barksdale Switches as well as different instrument j
spans?
Section 5.5 Gould Brown Relays:
i Why is calibration error zero?
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Span is recorded as 150.
What engineering units?
c Accuracy is recorded as 1.0.
Is that 1.0% of 150 t
span? Does 1.0 indicate +1.0/-l.0% span, or 40.5/-
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0.5% span, or +1.0/-0.0% span?
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10.
Please provide justification for elimination of 015D data which i
l deviated from the mean by more than 3 standard deviations for 10 or more data points.
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i 11.
To allow an adequate evaluation of the methodology utilized in the l
l study, a step by step description of the data retrieval, data entry i
i and data analysis methods used in the study must be provided for at I
least two instrument caannels.
Please select data for a typical RPS and ESTAS instrument channel which includes a process transmitter, signal conditioning equipment, and comparator/ trip unit.
Data should include applicable vendor specifications for instruments l
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channel calibratica data to determine confidence in calculated drift values.
Also provide basis for calibration errors included in analysis.
- 12. The referenced topical report discusses a staggered surveillance interval of 18 months.
Provide a discussion on the incorpuration of j
the proposed topical report 18 month staggered surveillance g
intervals into plants incorporating a 24 month fuel cycle.
Is it 1
the intent of the topical rerort to provide justification for l
extended 48 month surveillante intervals?
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- 13. The referenced topical report discusses the extension of 18 month l
calibration intervals based on drift analysis restalts included in the report.
The acceptability of extending calibration intervals is based on the analysis of plant as-left, as-found drift information.
Specifically, a methodology to project instrument drift over an extended period is presented in the topical report.
Earlier GE efforts at extending instrument surveillance from monthly to quarterly relied on BWP. models and a method of probabilistic assessment to provide a basis for extending Technical Specification surveillance intervals. The staff SERs accepted the GE methodology with the r 3at that instrument drift be evaluated and accounted for in the setpaint calculation and that the generic analysis was applicable to the plant specific case. Although the review guidance in GL 91-04 includes instrument drift as a significant factor in the i
evaluation of 24 montn surveillance intervals, GL 91-04 also requires an evaluation of maintenance and surveillanre histories.
The evaluation of extended calibration surveillance intervals on system availability is consistent with the guidance provided by GL 91-04 and may be the dominant consideration when evaluating the surveillance intervals proposed by the referenced topical report.
Based on the above, provide an evaluation on instrument and system availability (including'probabilistic assessment with drift evaluation) for calibration surveillance interval extensions as proposed in topical report NEDC-32160P.
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