ML20073C325
| ML20073C325 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 08/02/1994 |
| From: | Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| To: | Russell E NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20073C316 | List: |
| References | |
| CAW-94-705, NUDOCS 9409230244 | |
| Download: ML20073C325 (9) | |
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Energy Systems Nuclear Technology Division Westinghouse Electric Corporation eu 333 ,
Pittsburgh Pennsylvania 15230-0355 I August 2,1994 CAW-94-705 !
Document Control Desk US Nuclear R ilatory Commission I Washington, DC 20555 Attention: Mr. William T. Russell, Director APPLICATION FOR WITHHOLDING PROPRIETARY INFORMATION FROM PUBLIC DISCLOSURE
Subject:
" Elimination of Pressure Sensor Response Time Testing Requirements" (WCAP-13632, Revision 1, Proprietary)
Dear Mr. Russell:
l l The proprietary information for which withholding is being requested is further identified in Affidavit CAW-94-705 signed by the owner of the proprietary information, Westinghouse Electric Corporation.
The affidavit, which accompanies this letter, sets forth the basis on which the information may be I withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of 10 CFR Section 2.790 of the Commission's regulations.
l Accordingly, this letter authorizes the utilization of the accompanying Affidavit by Commonwealth l Edison Company.
l Correspondence with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference this letter, CAW-94-705, and should be addressed to the undersigned.
Very truly yours, l l
N, J. Liparul , Manager Enclosures Nuclear Safety Regulatory and Licensing Activities l cc: Kevin Bohrer/NRC (12H5) l l
l CIN448 RJMUU2e4 9409230244 940916 4 PDR ADOCK 0500
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CAW-94-705 l
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\ l l l l l COMMONWEALTH OF PENNSYLVANIA:
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COUNTY OF ALLEGHENY: l l
L Before me, the undersigned authority, personally appeared Henry A. Sepp, who, being by me l duly sworn according to law, deposes and says that he is authorized to execute this Affidavit on 1
1 behalf of Westinghouse Electric Corporation (" Westinghouse") and that the averments of fact set forth !
in this Affidavit are true and correct to the best of his knowledge, information, and belief:
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'7 l Henry A. Sepp, Manager l Regulatory and Licensing Initiatives !
l Sworn to and subscribed i
before me this 3 ~e c/
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_ day of 0'ocai,d ,1994 \
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l CAW-94-705 (1) I am Manager, Regulatory and Licensing Initiatives, in the Nuclear Technology Division, of the Westinghouse Electric Corporation and as such, I have been specifically delegated the l function of reviewing the proprietary information sought to be withheld from public disclosure in connection with nuclear power plant licensing and rulemaking proceedings, and am authorized to apply for its withholding on behalf of the Westinghouse Energy Systems !
Business Unit.
(2) I am making this Affidavit in conformance with the provisions of 10CFR Section 2.790 of the Commission's regulations and in conjunction with the Westinghouse application for withholding accompanying this Affidavit.
(3) I have pe sonal knowledge of the criteria and procedures utilized by the Westinghouse Energy Systems Business Unit in designating information as a trade secret, privileged or as confidential commercial or financial information.
(4) Pursuant to the provisions of paragraph (b)(4) of Section 2.790 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i) The information sought to be withheld from public disclosure is owned and has been i held in confidence by Westinghouse. j 1 i l (ii) The information is of a type customarily held in confidence by Westinghouse and not customarily disclosed to the public. Westinghouse has a rational basis for determining the types of information customarily held in confidence by it and, in that connection, ;
utilizes a system to determine when and whether to hold certain types of information I i in confidence. The application of that system and the substance of that system constitutes Westinghouse policy and provides the rational basis required, i
Under that system, information is held in confidence if it falls in one or more of j several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:
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l l (a) The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of
! Westinghouse's competitors without license from Westinghouse constitutes a l
competitive economic advantage over other companies.
(b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data l
- secures a competitive economic advantage, e.g., by optimization or improved l
l marketability.
1 l (c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product. l l
l (d) It reveals cost or price information, production capacities, budget levels, or l i commercial strategies of Westinghouse, its customers or suppliers, l
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(e) It reveals aspects of past, present, or future Westinghouse or customer funded l development plans and programs of potential commercial value to ,
l l Westinghouse.
l (f) It contains patentable ideas, for which patent protection may be desirable.
l l There are sound policy reasons behind the Westinghouse system which include the l
following:
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! %e use of such information by Westinghouse gives Westinghouse a (a) competitive advantage over its competitors. It is, therefore, withheld from disclosure to protect the Westinghouse competitive position.
(b) It is information which is marketable in many ways. The extent to which such information is available to competitors diminishes the Westinghouse ability to sell products and services involving the use of the information.
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l (c) Use by our competitor would put Westinghouse at a competitive disadvantage l by reducing his expenditure of resources at our expense.
(d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage. If competitors acquire components of proprietary information, any one component may be the key to the entire puzzle, thereby d:priving Westinghouse of a competitive advantage.
Unrestricted disclosure would jeopardize the position of prominence of i (e)
Westinghouse in the world market, and thereby give a market advantage to the competition of those countries. !
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(f) The Westinghouse capacity to invest corporate assets in research and development depends upon the success in obtaining and maintaining a competitive advantage.
(iii) The information is being transmitted to the Commission in con 6dence and, under the provisions of 10CFR Section 2.790, it is to be received in conGdence by the
- Commission.
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(iv) The information sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method to the best of our knowledge and belief.
(v) The proprietary information sought to be withheld in this submittal is that which is appropriately marked in " Elimination of Pressure Sensor Response Time Testing l Requirements", WCAP-13632 Revision 1 (Proprietary), December,1993 tbr Byron Units 1 and 2 and Braidwood Units 1 and 2, being transmitted by the Commonwealth Edison Company letter and Application for Withholding Proprietary Information from Public Disclosure, to the Document Control Desk, Attention William T. Russell. The proprietary information as submitted fbr use by Commonwealth Edison Company tbr the Byron Units 1 and 2 and Braidwood Units I and 2 is expected to be applicable in l
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other licensee submittals in response to certain NRC requirements for justification of the elimination of response time testing (RTT) requirements. ,
This information is part of that which will enable Westinghouse to:
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(a) Provide documentation in support of methods for the elimination of pressure sensor response time testing requirements. l (b) Provide the applicable similarity analysis for sensors not identified in the t EPRI report which establishes justification for RTT elimination for those sensors.
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(c) Provide data supporting elimination of RTT for certain sensors excluded by i the EPRI report.
l (d) Provide a methodology for substituting response times in lieu of values obtained from RTT for each sensor.
Further this information has substantial commercial value as follows:
(a) Westinghouse plans to sell the use of similar information to its customers for l
purposes of the elimination of response time testing (RTT) requirements.
l (b) Westinghouse can sell support and defense of the methodalogy in the licensing i
! process.
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l Public disclosure of this proprietary information is likely to cause substantial harm to I the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar methodologies and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.
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The development of the technology described in part by the information is the result of applying the results of many years of experience in an intensive Westinghouse effort and the expenditure of a considerable sum of money.
In order for competitors of Westinghouse to duplicate this information, similar technical programs would have to be performed and a signi6 cant manpower effort, having the requisite talent and experience, would have to be expended for developing the methodology.
Further the deponent sayeth not. !
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Copyright Notice The reports transmitted herewith each bear a Westinghouse copyright notice. The NRC is permitted to make the number of copies of the information cantained in these reports which are necessary for its internal use in connection with generic and plant specific reviews and approvals as well as the issuance, denial, amendment, transfer, renewal, medification, suspension, revocation, or violation of a license, permit, order, or regulation subject to the requirements of 10 CFR 2.790 regarding restrictions on public disclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding. With respect to the non-proprietary versions of these reports, the NRC is permitted to make the number of copies beyond those necessary for its internal use which are necessary in order to have one copy available for public viewing in the appropriate docket files in the public document room in Washington, DC and in local public document rooms as may be required by NRC regulations if the number of copies submitted is insufficient for this purpose. Copies made by the NRC must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.
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i Proprietary Information Notice Transmitted herewith are proprietary and/or non-proprietary versions of documents furnished to the NRC in connection with requests for generic and/or plant-specific review and appt tal.
In order to conform to the requirements of 10 CFR 2.790 of the Commission's regulations concerning the protection of proprietary information so submitted to the NRC, the information which is proprietary in the proprietary versions is contained within brackets, and where the proprietary information has been deleted in the non-proprietary versions, only the brackets remain (the information that was contained within the brackets in the proprietary versions having been deleted).
The justification for claiming the information so designated as proprietary is indicated in both versions by means of lower case letters (a) through (f) contained within parentheses located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (4)(ii)(a) through (4)(ii)(f) of the l
l affidavit accompanying this transmittal pursuant to 10 CFR 2.790(b)(1).
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WESTINGECUSE CLASS 3 (Nan-Propristcry)
WCAP-13787 Revision 1 ELIMINATION OF PRESSURE SENSOR RESPONSE TIME TESTING REQUIREMENTS WOG Program MUHP-3040 Revision 1 December, 1993
, Westinghouse Technical Specification Program Services WESTINGHOUSE ELECTRIC CORPORATION Nuclear and Advanced Technology Division P.O. Box 355 Pittsburgh, Pennsylvania 15230-0355
- 1993 Westinghouse Electric Corporation OL#% ,9 All Rights Reserved U\ 1% ,
LEGAL NOTICE "This report was prepared by Westinghouse as an account of work sponsored by the Westinghouse Owners Group (WOG). Neither the WOG, any member of the WOG, )
Westinghouse, nor any person acting on behalf of any of them:
(A) Makes any warranty or representation whatsoever, express or implied, (I) with respect to the use of any information, apparatus, method, process, or similar item disclosed in this report, including merchantability and fitness for a particular purpose, (II) that such use does not infringe on or interfere with privately owned rights, including any party's intellectual property, or (III) that this report is suitable to any
. particular user's circumstance; or (B) Assumes responsibility for any damages or other liability whatsoever
. (including any consequential damages, even if the WOG or any WOG representative has been advised of the possibility of such damages) resulting from any selection or use of this report or any information apparatus, method, process, or similar item disclosed in this report."
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l ACKNOWLEDGEMENTS The following personnel are recognized for their extended effcrts in the preparation of this report and for their team participation and support in the validation of material for this report.
C. E. Morgan Westinghouse Electric Corporation R. L. Bencini Westinghouse Electric Corporation R. B. Miller Westinghouse Electric Corporation J. D. Campbell Westinghouse Electric Corporation T. A. Lordi Westinghouse Electric Corporation J. L. Zielinski Westinghouse Electric Corporation L. Bush Commonwealth Edison Company - WOG H. Pontious Commonwealth Edison Company - WOG M. Eidson Southern Nuclear Operating Company - WOG T. A. Green General Electric Company D. Spencer Commonwealth Edison Company - BWROG b
ii
TABLE OF CONTENTS Section Title Pace 1.0 Executive Sumary 1-1 2.0 Introduction 2-1 3.0 Background 3-1 4.0 Suninary of Electric Power Research Institute (EPRI) 4-1 Report NP-7243 Revision 1, " Investigation of Response Time Testing Requirements".
4.1 Program Organization 4-1 4.2 Program Objectives 4-2 4.3 Plant Data collection and Assessment 4-3 4.4 Failure Modes and Effects Analysis (FMEA) 4-3 4.5 Summary of EPRI Recomendations 4-4 5.0 Westinghouse Analyses 5-1 5.1 Barton Model 752 Similarity Analysis Report 5-1 5.2 Barton Model 332 Similarity Analysis Report 5-7 5.3 Barton Model 351 Sealed Sensor System Analysis Report 5-13 5.4 Barton Model 763A Similarity Analysis Report 5 ./
5.5 Foxboro Model E11GM Similarity Analysis Report 5-20 5.6 Foxboro Model N-E11AH Similarity Analysis Report 5-23 5.7 Tobar Model 32DP2 Similarity Analysis Report 5-25 5.8 Tobar Model 32PA2 Similarity Analysis Report 5-30 5.9 Veritrak Model 76DP1 Similarity Analysis Report 5-35 5.10 Veritrak Model 76PG1 Similarity Analysis Report 5-40 5.11 Veritrak Model 76PH2 Similarity Analysis Report 5-45 6.0 Safety Benefits 6-1 7.0 Cost Benefits 7-1 iii
i 8.0 Safety Assessment For Increased Response Times Beyond 8-1 Current Technical Specification Limits 9.0 Program Methodology 91 10.0 Technical Specifications 10-1 11.0 Conclusions 10-1 12.0 References 10-1 List of Appendices
- Appendix Title Pace A Technical Specification Markups A-1 B Sample No Significant Hazards Evaluation (50.92) B-1 List of Figures Fiaure Title Page Figure 5.1-1 Barton Model 752 DPU 5-5 Figure 5.1-2 Barton Model 752 Block Diagram 5-6 Figure 5.2-1 Barton Model 224 Differential Pressure Unit 5-10 Figure 5.2-2 Barton Model 224 Mechanical Operation 5-11 Figure 5.2-3 Barton Model 332 Block Diagram 5-12 Figure 5.3-1 Typical Barton Model 351 Sensor Assembly 5-16 Figure 5.4-1 Barton Model 763A Block Diagram 5-19 Figure 5.5-1 Foxboro Model E-11GM Block Diagram 5-22 Figure 5.6-1 Foxboro Model N-E11AH Block Diagram 5-24 Figure 5.7-1 Tobar Model 32DP2 Amplifier Block Diagram 5-28 Figure 5.7-2 Tobar Model 320P2 Capsule Assembly 5-29 Figure 5.8-1 Tobar Model 32PA2 Amplifier Block Diagram 5-33 Figure 5.8-2 Tobar Model 32PA2 Capsule Assembly 5-34 Figure 5.9-1 Veritrak Model 76DP1 Amplifier Block Diagram 5-38 Figure 5.9-2 Veritrak Model 76DP1 Capsule Assembly 5-39 iv
List of Figures Ficure Title Paae Figure 5.10-1 Veritrak Model 76PG1 Amplifier Block Diagram 5-43 Figure 5.10-2 Veritrak Model 76PG1 Capsule Assembly 5-44 Figure 5.11-1 Block Diagram of the AC Amplifier for Veritrak 5-47 Model 76PH2 Figure 5.11-2 Veritrak Model 76PH2 Capsule Assembly 5-48 List of Tables Table Title Pace 9-1 Sensor Response Times 9-2 V
1.0 JXECUTIVE
SUMMARY
WOG Program MUHP-3040, Revision 1, deals with an effort by the industry to eliminate the specific Technical Specifications requirement to perform periodic response time testing on pressure and differential pressure sensors in Reactor Trip System and Engineered Safety Features Actuation System instrumentation loops. These pressure type sensors are utilized for flow, level, and pressure process measurement functions.
Specifically, MUHP-3040 Revision 1:
. o Utilizes the recomendations contained in EPRI Report NP-7243 Revision 1, " Investigation of Response Time Testing Requirements" for justifying elimination of response time
. testing surveillance requirements on certain pressure and differential pressure sensors identified in the report.
o Contains similarity analysis to sensors in the EPRI report of sensors not identified in the report to establish i justification for elimination of response time testing requirements for those sensors.
o Qualifies as a Cost Beneficial Licensing Action (CBLA) as described in section 7.0.
o Provides reasonable assurance that elimination of the specified response time testing requirements does not create a significant impact on the safety of the plant as described in section 8.0 o Provides a methodology for sub:tituting response times in lieu of values obtained from response time testing for each sensor covered by this WCAP.
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WOG program MUHP-3041, scheduled for completion in April of 1994, is complimentary to MUHP-3040. MUHP-3041 is being conducted to eliminate the specific requirement to perfonn periodic response time testing on the process instrumentation and logic portions of the Reactor Trip System and Engineered Safety Features Actuation System instrumentation loops.
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2.0 INTRODUCTION
Response Time Testing (RTT) of Reactor Trip System (RTS) instrumentation and Engineered Safety Features Actuation System (ESFAS) instrumentation has been required by Technical Specifications since the mid 1970's. The purpose of the RTT was to demonstrate that the instrumentation met the response time oerformance requirements assumed in the plant safety analyses.
Since its inception, RTT has proven to be resource intensive. RTT is generally performed in discrete steps, with the sensor response time being one of the steps. RTT of sensors is especially expensive, since
- many of the tests require special equipment and technical skills in addition to extensive test times. Furthermore, many of the sensors are located in radiation areas and substantial man rem exposure is incurred by plant maintenance staffs. A data review conducted by the EPRI has shown that RTT has not detected response time failures. This can be attributed in a large part to the fact that other surveillance (calibration) is typically perfonned first and has discovered failures that would affect response time. As a result, EPRI initiated a program to determine if RTT requirements could be eliminated for specific pressure and differential pressure transmitters and switches. The results of the EPRI program are delineated in EPRI Report NP-7243 Revisica 1 (Ref. 1).
This WCAP provides the technical justification for deletion of periodic RTT of selected pressure sensing instruments using the EPRI report recommendations and additional analysis by Westinghouse for selected sensors not addressed by the EPRI report. An example "No Significant Hazards Consideration" evaluation is included as Appendix B to aid the utilities in preparation of a plant specific license amendment request.
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3.0 BACKGROUND
In 1975 RTT requirements were added to the Westinghouse Standard Technical Specifications. As a result, all plants licensed after 1975 had to include RTT in routine surveillance testing. The first plant required by Technical Specifications to perform RTT was D. C. Cook Unit 1.
The Standard Technical Specifications contain definitions for both Reactor Trip System and Engineered Safety Features Actuation System Response Times. The response time definitions are:
"The REACTOR TRIP SYSTEM RESPONSE TIME shall be the time interval from when the monitored parameter exceeds its trip setpoint at the channel sensor until loss of stationary gripper coil voltage."
"The ENGINEERED SAFETY FEATURES RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its ESF actuation setpoint at the channel sensor until the ESF equipment is capable of performing its safety function (i.e., the valves travel to their required positions, pump discharge pressures reach their required values, etc.). Times shall include diesel generator starting and sequence loading delays where applicable."
The Bases section states that the response time may be measured by any series of sequential, overlapping, or total steps such that the entire response time is measured. This approach is also consistent with ISA Standard 67.06. Given this guidance and the complexity of testing an entire instrument channel from the sensor to the final device, plant surveillance procedures typically test a channel in two or more steps.
One individual step in most plant test methodologies is the instrument sensor. Separate procedure (s) using specialized test equipment and/or outside vendors are typically used solely for sensor testing.
The first industry RTT guidelines were established by the Institute of Electrical and Electronic Engineers in ANSI /IEEE Standard 338-1975,
" Criteria for the Periodic Testing of Class 1E Power and Protection Systems." In 1977 this Standard was revised and accepted by the NRC as documented by NRC Regulatory Guide 1.118, " Periodic Testing of Electric Power and Protection Systems," Revision 1. Following Revision 2 of Regulatory Guide 1.118, the Instrument Society of America approved Standard ISA 567.06, " Response Time Testing of Nuclear Safety-Related Instrument Channels in Nuclear Power Plants," August 29, 1986. These guidelines have also been used by. industry when developing plant specific test procedures.
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4.0 Sumary of EPRI Report NP-7243 Revision 1," Investigation of Response Time Testing Requirements".
In May of 1991, EPRI issued a report " Investigation of Response Time Testing Requirements", Report No. NP-7243. EPRI is publishing revision 1 to this report to address additional comments by the industry (Ref.
1). The EPRI report provides recomendations for reducing or eliminating RTT requirements which apply to typical pressure and differential pressure sensors used in safety-related protection system instrumentation in the nuclear power industry.
The primary purpose of the EPRI investigation was to determine if deleting RTT could be justified for specific pressure, level, and flow sensors. IEEE Standard 338-1977 defines a basis for eliminating RTT.
Section 6.3.4 states in part:
" Response time testing of all safety-related equipment, per se, is not required if, in lieu of response time testing, the response time of the safety system equipment is verified by functional testing, calibration check, or other tests, or both."
In addition, the standard states:
"This is acceptable if it can be demonstrated that changes in response time beyond acceptable limits are accompanied by changes in performance characteristics which are detectable during routine periodic tests."
4.1 Program Organization The EPRI report was developed thr iugh the efforts of EPRI, the RTT Utility Advisory Committee (UAC), :.' nuclear power plants, 6 pressure sensor manufacturers, Science Applications International Corporation (SAIC) and Performance Associates, Inc. EPRI coordinated the program and acted as technical director and reviewer. The RTT UAC acted as advisors on the formulation of the project and as reviewers during the development of the report. The 39 plants provided detailed response time data used in the investigation to determine failure trends, test methods and data repeatability. The 6 manufacturers, which supplied technical information regarding the design and performance of their product (s), represented the majority of manufacturers currently providing qualified pressure sensors to the nuclear industry. SAIC and Perfonnance Associates, Inc. performed the RTT investigation and developed the report. Rosemount FMEA data included in the report was provided by the EPRI Project Manager.
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4.2 Program Objectives In support of industry efforts to improve plant availability and reduce plant personnel exposure levels, EPRI established a program to determine whether or not requirements for RTT of specific pressure and differential pressure transmitters and switches could be eliminated.
The investigation included only the sensor since the premise for deleting RTT of the sensor was not directly applicable to the other components in the instrument loop. Therefore, the conclusions and recommendations of the EPRI report are applicable only to the sensor portion of the instrument loop.
The EPRI procram was devised to determine: 1) how RTT performs as a
- unique indicator of sensor (pressure and differential pressure) response time degradation; 2) sensor failure modes, if any exist, which result in response time degradation that would not be detected by other periodic (non-RTT) testing methods; 3) the level of redundancy between RTT and other periodic tests; and, 4) the RTT methods best suited to detect, where necessary, response time degradation.
Assessment of plant response time data and performance of FMEAs on sensor hardware provided the mechanisms for obtaining the necessary infonnation. For the plant data assessment, evaluations were performed to establish any similarities and differences in response time testing at selected plants and to determine the repeatability of RTT mecsurements. Sensor types were identified as either having failed response time testing, or as trending toward failure. Root causes of known sensor failures were evaluated to determine if response time degradation was the key indicator of the failure. Additionally, the use of response time measurement data to identify sensors that were trending toward response time failures was evaluated.
FMEA considerations included the evaluation of sensor failure modes l which could affect response time, the ways that sensors which are experiencing response time degradation exhibit other operability
. changes, and the identification of routine plant tests that essentially previde the same information as RTT for each response time failure mode.
4.3 Plant Data Collection and Assessment For the EPRI investigation, 39 r.uclear power plants supplied over 4200 RTT measurements including information regarding sensor type, sensor use, instrument range, trip setpoint, allowable response time, test method, and type of test system. The plant data covered all but one manufacturer (Statham) supplying safety-related pressure and l differential pressure sensors to the nuclear industry. EPRI used this data to determine failure trends and evaluate test methods and data l repeatability. Six manufacturers, including Statham, supplied EPRI with technical information regarding design and performance of their 4-2
products. Sensor failure modes affecting response time were evaluated to the guidelines provided in ANSI N41.4-1976/IEEE Std 352-1975 "IEEE Guide for General Principles of Reliability Analysis of Nuclear Power Generating Station Protection Systems" to confirm that response time failures could be detected by surveillance tests other than specific RTT.
Based on the 4200 measurements supplied, the EPRI investigatir.n found "RTT has not identified any sensors that have failed response time requirements using hydraulic or electronic white noise analysis techniques. However, calibrations and other tests have detected transmitters with excessive response times".
. The EPRI report concludes that the current RTT program for pressure and differential pressure sensors adds very little to the identification of failed sensors and verification of loop response times. With a few
. exceptions (noted in Section 4.5), the existing instrumentation surveillance requirements, such as channel checks and sensor calibrations, have proven effective in identifying failed sensors in a timely manner.
4.4 Failure Modes and Effects Analysis The EPRI report included FMEAs on the following sensor-types:
Barton 288/289 Differential Pressure Indicating Switches Barton 763 Gauge Pressure Transmitter Barton 764 Differential Pressure Transmitter Foxboro/ Weed N-E11DM Differential Pressure Transmitter Foxboro/ Weed N-E13DM Differential Pressure Transmitter Foxboro/ Weed N-E13DH Differential Pressure Transmitter Foxbero/ Weed N-E11GH Gauge Pressure Transmitter Foxboro/ Weed N-E11GM Gauge Pressure Transmitter Tobar 32PA1 Absolute Pressure Transmitter Tobar 32PG1 Gauge Pressure Transmitter i- Tobar 32DP1 Differential Pressure Transmitter l Rosemount Differential Pressure Transmitter Models 1151, 1152, l 1153, 1154 Rosemount Pressure Transmitter Models 1151, 1152, 1153, 1154 Statham PD-3200 Differential Pressure Transmitter Statham PG-3200 Pressure Transmitter SOR Differential Pressure Switch SOR Pressure Switch.
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l These sensor types were selected as being representative of the pressure and differential pressure sensor instrumentation being utilized in safety-related systems and are representative of the various sensor designs (e.g., bourdon tube, force-balance, capacitance and strain gauge).
The FMEA method of analysis provided a systematic approach for identifying failure modes. The FMEAs permitted the identification and analysis of failure modes associated with each principal design component of the pressure and differential pressure sensors that could affect response time.
4.5 Summary of EPRI Recommendations The EPRI report provides recommendations for modifying the current RTT program for pressure and differential pressure sensors in the nuclear utility industry. These are recommendations to consider when enhancing or upgrading existing plant RTT programs and are not intended to require changes to current plant RTT programs.
The report also provides the basis for deletion of all periodic pressure and differential pressure sensor response time testing requirements subject to following exceptions / limitations:
- 1. Perform hydraulic response time test prior to installation of new transmitter / switch or following refurbishment.
- 2. For transmitters and switches that use capillary tubes, RTT should be performed after initial installation and after any maintenance or modification activity that could damage the capillary tubes.
- 3. Perform periodic drift monitoring on all Rosemount pressure and differential pressure transmitters in accordance with Rosemount Technical Bulletins and NRC Bulletin 90-01 (affects certain model numbersonly).
Note: NRC Bulletin 90-01 has been superseded by NRC Bulletin 50-01 Supplement 1.
- 4. Assure that variable damping (if used) is at the required setting and cannot be changed or perform hydraulic or white noise response time testing of sensor, following each calibration.
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I 5.0 Westinghouse Owners Group Analyses The primary objective of the following similarity analysis is to provide justification for deleting Technical Specifications requirements for RTT on pressure and differential pressure sensors not included in EPRI Report NP-7243.
In 1991 a survey was made of Westinghouse Owners Group plants to provide inforretion identifying those pressure and differential pressure sensors currently in operation with periodic Technical Specifications RTT requirements. Following is a list of pressure and differential pressure I sensors identified from that survey which are in addition to those evaluated in the EPRI report:
Barton 752 Differential Pressure Transmitter Barton 332 Differential Pressure Transmitter Barton 763A Gauge Pressure Transmitter Barton 351 Sealed Sensor Foxboro/ Weed N-EllAH Absolute Pressure Transmitter Foxboro E11GM Gauge Pressure Transmitter Tobar 32DP2 Differential Pressure Transmitter Tobar 32PA2 Absolute Pressure Transmitter Veritrak 76DP1 Differential Pressure Transmitter Veritrak 76PG1 Gauge Pressure Transmitter Veritrak 76PH2 Absolute Pressure Transmitter.
Similarity analyses were utilized to canpare the design and the functionality of the principal components of each pressure and differential pressure unit, to those evaluated in the EPRI report. For those instruments where similarity could not be shown, other techniques (FMEA, historical approach, circuit testing) were utilized to justify elimination of the RTT requirerents. The respective sensor manufacturer has reviewed / approved each Westinghouse analysis contained herein.
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5.1 BARTON MODEL 752 SIMILARITY ANALYSIS REPORT 5.1.1 Description
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5.2 BARTON MODEL 332 SIMILARITY ANALYSIS REPOR7 5.2.1 Description
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6.0 Safety Benefits Reduction in the amount of response time testing requirements results in improvement in plant safety by:
. Increasing the availability of equipment. The response time tests typically require that instruments be removed from service in order to perform the test. The time period can range several hours to several days depending on the type of test. By eliminatirig or reducing unnecessary testing, the plant safety is improved.
- Decreasing the possibility of unwanted engineered safety features
. actuations. Some of the testing requires that equipment be placed :
in the trip' condition. Improper return to service or other l malfunctions that occur while testing may lead to plant trips or
- inadvertent actuation of equipment. By eliminating or reducing l unnecessary testing, the plant safety is improved.
. Decreasing radiation exposure. Sensors are typically located in j radiation areas to minimize the sensing line lengths. Eliminating l unnecessary testing on these sensors reduces exposures consistent i with the guidelines of ALARA.
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7.0 Cost Benefits ,
The EPRI report data indicated that RTT was both resource and exposure (ALARA) intensive. The process noise method of RTT for pressure sensors is often performed by an outside vendor (AMS or Westinghouse) and can cost $30K - $45K per unit per outage for a 4 loop plant (based on recent bids at Zion and Braidwood Stations). The hydraulic ramp generator test method of RTT, an alternate method to process noise and the usual method for those pressure transmitters with no process noise, can take up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> per transmitter to perform (based on procedures used at Braidwood Station). An individual utility cost saving would depend on the test method (s) and plant procedures used and whether or not an outside vendor is used for some or all of the work.
The overall response time of a channel is generally obtained by combining the times from the Segments shown below:
FIGURL 1 I
OVERLAP OVERLAP OVERLAP SEGMENT 1 SEGMENT 3 SEGMENT 2 SEGMENT 4 PROCESS SSPS OR FINAL DEVICE, SENSORS 7300, 7100, RELAY RODS FREE TO FALL, EAGLE LOGIC OR ESF COMPONENTS OBTAIN SAFETY P05.
! NIS
- l. The manpower required to do response time testing on Segments 1, 2, and 3 shown above is estimated by the WOG to be between 900 and 2000 manhours.
Both the BWR Owners Group and EPRI estimated that the manpower required to do this response time testing could range between 1500 and 2600 manhours.
Using a conservative estimate, shown below, one can see a significant utility cost savings.
Manhours 900 (per 18 month cycle)
Cost /hr $24.00 (includes benefits) l Success 75%
Rate
- 900 hrs x $24.00/hr x 75% = $16,200.00
- Percent of total hours for RTT surveillance requirements eliminated I
7-1
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i
' 8.0 Safety Assessment For Increased Response Times Beyond )
Current Technical Specification Limits The WOG programs outlined in Section 1.0 demonstrate the capability of l the calibration surveillance to detect failures that would affect I response time on sensors, signal conditioning, and logic equipment. I Typical allowances include 400 milliseconds for differential pressure sensors, 200 milliseconds for pressure sensors, and 100 milliseconds each for the signal conditioning and logic. For most applications significant information exists in the form of test data from manufacturers and from the industry that pressure and differential pressure sensors have. response times that could be a factor of ten below these allowances. In addition, FMEAs (with test verification) have been ;
performed on the signal conditioning and logic portions of the j Westinghouse instrumentation and have shown with reasonable assurance i that response times of the signal conditioning will not increase above the 200 milliseconds allowance. Summing of the above more conservative response times results in total response times well within the values )
allowed in the Technical Specifications.
However, as added assurance, a maximum incredible response time for each reactor trip function was calculated by increasing the sensor, signal conditioning, and logic each by a factor of five and applying the root mean square method since the degradation of response time of each
. portion of the system would be independent. The results of the root mean square method show that containment pressure measurement response time matches the Technical Specification and for level and flow functions, which utilize differential pressure transmitters, the highest response time calculated was 2.4 seconds. In all cases, even without applying the root mean square method, the response time obtained for functions with pressure transmitters was still below the Technical j Specification value.
I Eny:neered Safety Features response times, where the required response time corresponds to the diesel start time, are excluded from surnillance by NRC Generic Letter 93-05. Since LOCA and steamline i break analyses utilize pressure and containment pressure measurements as primary functions and the SGTR analyses is conservatively performed assuming no delay, the only potential impact to the safety analyses j results involves transients that credit level and flow measurements as l primary reactor trips or ESF functions with response times less than the diesel start time.
- Low reactor coolant flow reactor trip is credited in the partial loss of flow analysis and the locked rotor event. With the margins assumed, the response time would increase from 1.0 to 2.4 seconds.
4
. The partial loss of flow event is bounded by the complete loss of flow analysis in terms of consequences and would continue to be bounded even with the projected time response increase. This more limiting event satisfies condition II criteria of no fuel failure.
1 1
8-1 .
l l
i i 8.0 Safety Assessment For Increased Response Times Beyond ,
Current Technical Specification Limits (continued) !
' 1
- The locked rotor event is classified as a condition IV event <
! that allows fuel failure to occur. With the projected
- increased response time, better estimate assumptions (e.g.
j consistent power shape in the transient reactivity feedback
- and DNBR analysis, actual moderator temperature coefficient) would yield similar results. The peak reactor coolant system pressure is expected to increase less than 2.0% and j the maximum clad temperature and ZR-H,0 reaction criteria 2
would not be exceeded.
4 i'
- High steam generator water level ESf functions are credited in the i feedwater malfunction event. With tre margins assumed including a 3 .25 second turbine stop valve closure time, the response time i, would still be below the Technical Specification value.
5 = Lo-lo steam generator water level reactoc trip is used in the loss ,
! of normal feedwater/ station blackout event, the feedline break l l even, the loss of load / turbine trip event, and the determination
! of mass / energy release outside containment. With the margins l assumed, the response time would increase from 2.0 to 2.4 seconds.
l This trip function is not required for protection for a DNB l 1 condition, so no fuel failure would be expected due to the I j projected increase in response time. The effect of the increased l q response time on the DNB transient, pressurizer overfill, reactor j coolant system subcooling, and the results of the mass / energy j release outside containment would be negligible.
)
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8-2
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- 9.0 Program Methodology ;
y l Each sensor that has been identified as a candidate for elimination of
- periodic response time testing requirements is listed in Table 9-1. The response time to be allocated in place of response times obtained
~
through actual measurement during the period of verification may be obtained from: (1) historical records based on acceptable response time tests (hydraulic, noise, or power interrupt tests), (2) inplace, onsite, or offsite (e.g. vendor) test measurements, or (3) utilizing vendor engineering specifications. There is no specific recomendation, although the value will be increasingly more conservative progressing through these methods. Available values have been incorporated into the !
table. An explanation for use 'of Table 9-1 is provided below, i
- 1. Determine the type of sensor being used for each reactor trip or engineered safety features function that requires periodic
. response time verification per the plant Technical Specifications.
- 2. Verify that these sensors are included in Table 9-1.
- 3. Obtain the sensor response time from Table 9-1. If the sensor response time is not provided in the Table, then neither the manufacturer nor Westinghouse currently provide this information.
Fill in the Baseline column using the most conservative data obtained from either previous plant insitu response time testing or, if replacing the transmitter, the response time obtained through testing.
- 4. Ensure that the plant test procedures are written such that the sensor response time is accounted for separately from the rest of I the protection channel. (If this is not the case, incorrect overall times may be obtained because Table 9-1 values only !
account for the sensor portion of the protection channel.)
- 5. Incorporate the sensor response time acceptance criteria in the plant procedures.
- 6. Obtain the response time for the remainder of the reactor trip or
. engineered safety features function.
- 7. Add the sensor response time to the response time for the remainder of the protection channel and verify that the total is less than the value for that function given in the plant Technical Specifications or FSAR.
9-1
Table 9-1 Sensor Response Times i Response Time Model Baseline Manufacturer Westinghouse Manufacturer Number Description (1) Supplied E Spec BARTON 288 Differential Pressure Indicating Switch BARTON 289 Differential Pressure Indicating Switch BARTON 332 Differential Pressure Transmitter BARTON 351 Sealed Sensor 1 sec BARTON 752 Differential Pressure Transmitter 30 msec 400 msec BARTON 763 Gauge Pressure Transmitter 180 msec 200 msec 4
BARTON 763A Gauge Pressure Transmitter 180 msec 200 msec BARTON 764 Differential Pressure Transmitter 180 msec 400 msec FOXBORO E11GM Gauge Pressure Transmitter FOXBORO/ WEED N-E11AH Absolute Pressure Transmitter FOXBORO/ WEED N-E11DM Differential Pressure Transmitter FOXBOR0/ WEED N-E11GH Gauge Pressure Transmitter FOXBOR0/ WEED N-E11GM Gauge Pressure Transmitter FOXBOR0/ WEED N-E13DH Differential Pressure Transmitter FOXBORO/ WEED N-E13DM Differential Pressure Transmitter (1) Utilize the most conservative value for response time obtained from either previous plant insitu response time testing or, if replacing the transmitter, the response time obtained through testing.
9-2 1
Table 9-1 Sensor Response Times Response Time Model Baseline Manufacturer Westinghouse Manufacturer Number Description (1) Supplied E Spec ROSEMOUNT 1151 Pressure Transmitter ROSEMOUNT 1152 Pressure Transmitter ROSEMOUNT 1153 Pressure Transmitter ROSEMOUNT 1154 Pressure Transmitter ROSEMOUNT 1151 Differential Pressure Transmitter ROSEMOUNT 1152 Differential Pressure Transmitter ROSEMOUNT 1153 Differential Pressure Transmitter ROSEMOUNT 1154 Differential Pressure Transmitter T0BAR 32DP1 Differential Pressure Transmitter 400 msec TOBAR 32DP2 Differential Pressure Transmitter 400 msec TOBAR 32PA1 Absolute Pressure Transmitter ,
200 msec TOBAR 32PA2 Absolute Pressure Transmitter 200 msec TOBAR 32PG1 Gauge Pressure Transmitter 200 msec VERITRAK 76DP1 Differential Pressure Transmitter 400 msec VERITRAK 76PG1 Gauge Pressure Transmitter 200 msec VERITRAK 76Pil2 Absolute Pressure Transmitter 200 msec (1) Utilize the most conservative value for response time obtained from either previous plant insitu response time testing or, if replacing the transmitter, the response time obtained through testing.
9-3
l 1
10.0 Technical Specifications Appendix A contains a markup of the recommended Technical Specifications to be used when eliminating the requirements for actual measurement of response times on Reactor Trip and Engineered Safety Features Systems.
This change does not represent a significant hazard to the public as evaluated in accordance with the requirements of 10 CFR 50.92. See Appendix B. l
11.0 CONCLUSION
S By utilizing the recommendations of EPRI Report NP-7243 Revision 1, i
" Investigation of Response Time Testing Requirements", justification is
. established for eliminating response time testing surveillance i requirements for the pressure and differential pressure sensors covered j by that report. Justification for eliminating additional sensors has
- been documented by this WCAP by showing similarity to those sensors included in the EPRI report. Where similarity could not be shown, FMEA or testing demonstrated that the time response would not be significantly effected by degradation of components or that such changes would be detectable by normal calibration procedures. All sensors that have been justified by the above methods appear in Table 9-1.
12.0 REFERENCES
- 1. EPRI NP-7243 Revision 1. " Investigation of Response Time Testing Requi rements" . 1 1
- 2. EPRI TR-103436, Volume 2, Instrument Calibration and Monitoring Program
- Failure Modes and Effects Analysis.
l l
c 10-1 i
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APPENDIX A a
' Docket No. 50-445 3/4.3 INSTRUMENTATION August 14, 1987 3/4.3.1 REACTOR TRIP SYSTEM INSTRUMENTATION j
LIMITING CONDITION FOR OPERATION
'l 4
i 3.3.1 As a sinistas, the Reacter Trip Systas instrumentation channels anc interlocks of Taale 3.3-1 shall be OPERABLE with RESPONSE TIMES as shown in i Table 3.3-2.
J .
APPLICA8!LITY: As shown in Table 3.3-1.
ACTION:
li As shown in Tatie 3.3-1.
l 50RVEILL NCE REQUIREMENTS 2
l 4.3.1.1 Each Reacter Tri6 System instrueentation channel and interlock and the avtamatic trip logic *shall be demonstrated OPERABLE by the performance of
- the Reactor Trip Systaa Instrumentation Surveillance Requirements specified in i
Tatie 4.3-1.
1 4.3.1.2 The REACTOR TRIP'5YSTEM RESPONSE TIM of each teacter trip function 4
shall be n --- nat to be within its limit at least once per la months.
- . Each shal inclues at least one train such that both trains are ^xtd at 1 cast a per months and one channel per function such that 41 c nnels i
cre at le t once every N times 18 months where N is the tal number of red tc 1s in a specific teacter trip function as in the
- " Total e. 1s* colmi of Table 3.3-1.
j . l f
verification verified verified l
CDMAncME PEAK - UNIT 1 3/4 3-1 i
l
- A-1 i
4 I
! APPENDIX A l
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INSTRUMENTATION Becket tio. 50-445 j Augggt }4,ggg7 SURVEILLANCE REQUIREMENTS 4
4.3.2.1 Each ESFAS instrumentation channel and interlock and the automatic i .
actuation logic and relays shall be demonstrated OPERABLE by performance of
} the ESFA5 Instrumentation Surveillance Requirements specified in Table 4.3-2.
4.3.2.2 The ENGINEERED SAFETY FEATURES RESPONSE TIM of each ESFAS function i* shall be :: ::.; =^2d to be within the limit at least once per 18 months.
Eme" _:;^ shall include at least one train such that both trains are ^^;;:d at f least once per months and one channel per function such that al nnels i are 'r-" at les t once per N times 18 months where N is the I nacer
] of redu t chan is in a specific ESFAS function as s n the " Total j Me. of Chan Is" co uun of Table 3.3-3.
i j v.riticaton veriti.d v.riri.d 1
COMMcHE PEAK - UNIT 1 3/4 3-17 A-2
APPENDIX A INSTRUMENTATION Socket No. 50-445 BASES August 14, 1987 REACTOR TRIP SYSTEM and ENGINEERED SAFETY FEATURES ACTUATIO IN5 RUMENTATION (continueo) the sensor from its calibration point or the v'alue specified in Table 3.3-4, in percent span, from the analysis assumptions. Use of Equation 3.3-1 allows for a sensor craf t factor, an increased rack drift factor, and provides a threshold value for REPORTABLE EVENTS.
' The methodology to derive the Trip Setpoints is based upon combining all of the uncertainties in the channels. Inherent to the determination of the Trip 5etpoints are the magnitudes of these channel uncertainties. Sensor and rack instrumentation utilized in these channels are expected to be capable of operating within the allowances of these uncertaiknty magnitudes. Rack drift in excess met of the Allowable Value exhibits the behavior that the rack has not its allowance. Being that there is a small statistical chance that this will happen, an infrequen.t excessive drift is expected. Rack or sensor drift, in excess of the allowance that is more than occasional, say be indicative of more serious problems and should warrant further investigation.
asurement of response time at the specified frequencies provi assurance Reactor trip and the Engineered Safety Featu uation associated with ese 1 is completed within the ti '
assumed in the 1nSeri safety analyses. No credit in the anal or those channels with response times indicated as not app -_a '
pense time may be demonstrated by any series of sequential, over *
, or channel test measurements provided that such tests Sensor response ti rate the total cM; . ~ nse time as defined.
ication may be demonstrated by ei ) in place, onsi offsite test seasurements, or (2) utilizing replac sen th certified response ties.
The Engineered Safety Features Actuation System senses selected plant parameters and determines whether or not predetermined limits are being exceeded.
If they are, the signals are combined into logic matrices sensitive to comeina-tiens indicative of various accidents events, and transients. Once the required logic combination is completed, the systas sends actuation signals to those Engineered safety Features components whose aggregata function best serves the requirements of the condition. As an example, the following actions may be initiated by the Engineered safety Features Actuation System to sitigate the consequences of a steen line break or less-of-coolant accident: (1) Safety Injection pumps start and automatic valves position. (2) Reactor trip, (3) feed water isolation, (4) startup of the emergency diesel generators, (5) containment
. spray pumps start and automatic valves position (6) containment isolation, 4 (7) steam line isolation, (8) tuttiine trip, (9) auxiliary feedwater pisups start and automatic valves position, (10) containment cooling fans start and automatic valves position, (11) essential service water pumps start and auto-matic valves position, and (12) Control Room Isolation and Ventilation Systems
. start.
CDMANCHE PEAK - UNIT 1 B 3/4 3-2 A-3
- - -m..
I APPENDIX A INSERT A The verification of response time at the specified frequencies provides assurance that the reactor trip and the engineered safety features i
actuation associated with each channel is completed within the time I
limit assumed in the safety analyses. No credit was taken in the analyses for those channels with response times indicated as not applicable. Response time may be verified by actual tests in any series i . of sequential, overlapping or total channel measurements, or by sumation of allocated sensor response times with actual tests on the remainder of the channel in any series of sequential or overlapping measurements. Allocations for sensor response times may be obtained from: (1) historical records based on acceptable response time tests (hydraulic, noise, or power interrupt tests), (2) inplace, onsite, or offsite (e.g. vendor) test measurements, or (3) utilizing vendor
! engineering specifications. WCAP-13632 Revision 1, " Elimination of Pressure Sensor Response Time Testing Requirements" provides the basis and methodology for using allocated sensor response times in the overall verification of the Technical Specifications channel response time. The allocations for sensor response times must be verified prior to placing the sensor in operational service and re-verified following maintenance that may adversely affect response time. In general, electrical repair work does not impact response time provided the parts used for repair are of the same type and value. One example where time response could be affected is replacing the sensing assembly of a transmitter.
l l
l A-4
i APPENDIX B -Doc. #
Revision Page 1 of 5 WESTINGHOUSE NUCLEAR SAFETY DEPARTMENT SIGNIFICANT HAZARDS CONSIDERATION ANALYSIS
- 1) NUCLEAR PLANT (S):
- 2)
SUBJECT:
Response Time Testina Deletion - Pressure Sensor l
l TECHNICAL SPECIFICATIONS CHANGED: 4.3.1.2 and 4.3.2.2 " Instrumentation-3)
. Surveillance Recuirements. B 3/4.3.1 and B 3/4.3.2 " Reactor Trio and l Encineered Safetv Features Actuation System Instrumentation" l
- 4) A written analysis of the significant hazards consideration, in accordance with the three factor test of 10CFR50.92, of a proposed license amendment to implement the subject change has been prepared and ,
is attached. On the basis of the analysis, the checklist below has been l completed.
Will operation of the plant in accordance with the proposed amendment:
4.1) Yes No X Involve a significant increase in the probability or consequences of an accident previously evaluated:
4.2) Yes No X Create the possibility of a new or different kind of accident from any accident previously evaluated; 4.3) Yes No X Involve a significant reduction in margin of safety.
- 5) Reference Documents:
- 1. WCAP-13632 Revision 1, " Elimination of Pressure Sensor Response Time Testing Requirements"
- 2. (List of Applicable Sensors)
- 6) Comments: None l
l Prepared by (Nuclear Safety):
Date:
Verified by (Nuclear Safety): l Date:
Coordinated with Engineer (s):
Date:
1 Nuclear Safety Group Manager:
Date: !
i B-1 !
1 i 4
..I
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APPENDIX B Doc. # j Revision i Page 2 of 5 j l
l PLANT NAME I PRESStJRE SENSOR RESPONSE TIME TESTING DELETION l SIGNIFICANT HAEARDS CONSIDERATION ANALYSIS I INTRODUCTION )
In 1975 response time testing (RTT) requirements were included in the Westinghouse Standard Technical Specifications and were required for all l plants licensed after that date.
The Standard Technical Specifications contain definitions for both Reactor Trip System and Engineered Safety Features Actuation System response times.
The response time definitions are:
"The REACTOR TRIP SYSTEM RESPONSE TIME shall be the time interval from when the monitored parameter exceeds its trip setpoint at the channel sensor until loss of stationary gripper coil voltage."
"The ENGINEERED SAFETY FEATURES RESPONSE TIME shall be that time interval from when the monitored parameter exceeds its ESF :
actuation setpoint at the channel sensor until the ESF equipment ~l is capable of performing its safety function (i.e., the valves i travel to their required positions, pump discharge pressures reach i their required values, etc ). Times shall include diesel generator j starting and sequence loading delays where applicable."
The Bases section states that the response time may be measured by any series of sequential, overlapping, or total steps such that the entire response time is measured. This approach is also consistent with ISA Standard 67.06. Given this guidance and the complexity of testing an entire instrument channel from the sensor to the final device, plant surveillance procedures typically test a
- channel in two or more steps. One individual step in most plant test methodologies is the instrument sensor. Separate procedures using specialized test equipment and/or outside venders are typically used solely for testing
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the sensors.
The first RTT guidelines were established by the Institute of Electrical and j Electronic Engineers in ANSI /IEEE Standard 338-1975, " Criteria for the Periodic Testing of Class IE Power and Protection Systems". In 1977 this Standard was revised and accepted by the NRC with NRC Regulatory Guide 1.118,
" Periodic Testing of Electric Power and Protection Systems", Revision 1.
Following Revision 2 of the Regulatory Guide 1.118, the Instrument Society of America approved Standard ISA S67.06, " Response Time Testing of Nuclear Safety-Related Instrument Channels in Nuclear Power Plants" August 29, 1986.
This significant hazards consideration analysis applies to the proposed l deletion of periodic time testing requirements for certain pressure and differential pressure transmitters and switches from the Technical Specifications.
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DESCRIPTION OF THE AMENDMENT REQUEST j I
As required by 10 CFR 50.91 (a)(1), an analysis is provided to demonstrate that the proposed license amendment to delete the requirement for certain j pressure and differential pressure sensor response time testing involves no significant hazards consideration. The proposed amendment, described in Reference 1, would modify Surveillance Requirements 4.3.1.2 and 4.3.2.2 >
Technical Specifications 3/4.3.1, " Reactor Trip System Instrumentation" and ]
3/4.3.2, " Engineered Safety Feature Actuation System Instrumentation" and B 3/4.3.1 and B 3/4.3.2 " Reactor Trip and Engineered Safety Features Actuation
. System Instrumentation" to indicate that the total response time will be determined based on the results of Reference 1 for pressure sensors. ,
l EVALUATION l
l The primary purpose of this evaluation is to determine if the deletion of periodic response time testing could be justified for specific pressure, level, and flow functions that utilize pressure and differential pressure sensors. IEEE Standard 338-1977 defines a basis for eliminating RTT. Section
6.3.4 states
" response time testing of all safety-related equipment, per se, is not required if, in lieu of response time testing, the response time of the safety system equipment is verified by functional testing, calibration i
check, or other tests, or both."
l WCAP-13632 Rev. 1 (Reference 1) provides the technical justification for deletion of periodic response time testing of selected pressure sensing instruments. The program described in the WCAP utilizes the recommendations contained in EPRI Report NP-7243 Rev. 1, " Investigation of Response Time Testing Requirements" for justifying elimination of response time testing surveillance requirements on certain pressure and differential pressure sensors. To address other sensors installed in Westinghouse designed plants, the WCAP contains a similarity analysis to sensors in the EPRI report or an FMEA to provide justification for elimination of response time testing requirements. The specific sensors installed (Reference 2) at (Plant Name) are listed below.
- Steam Generator Water Level (Manufacturer / Model)
- Pressurizer Pressure (Manufacturer / Model)
- Steamline Pressure (Manufacturer / Model)
- Containment Pressure (Manufacturer / Model)
- Reactor Coolant Flow (Manufacturer / Model)
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Revision Page 4 of 5 The basis for eliminating periodic response time testing for each sensor is discussed in the WCAP and/or the EPRI report. These reports provide justification that any sensor failure that significantly degrades response time will be detectable during surveillance testing such as calibration and ,
channel checks. )
Based on these results, the (Plant Name) Technical Specifications ate being revised to indicate that the system response time shall be verified utilizing a sensor response time justified by the methodology described in WCAP -13632 Revision 1. Allocations for sensor response times may be obtained from: (1) historical records based on acceptable response time tests (hydraulic, noise,
, or power interrupt tests), (2) inplace, onsite, or offsite (e.g. vendor) test measurements, or (3) utilizing vendor engineering specifications.
AMALYSIS Conformance of the proposed amendment to the standards for a determination of no significant hazard as defined in 10 CFR 50.92 is shown in the following:
- 1) The proposed license amendment does not involve a significant increase in the probability or consequences of an accident previously evaluated.
This change to the Technical Specifications does not result in a condition where the design, material, and construction standards that were applicable prior to the change are altered. The same RTS and ESFAS instrumentation is being used; the time response allocations /modeling j assumptions in the Chapter 15 analyses are still the same; only the l method of verifying time response is changed. The proposed change will )
not modify any system interface and could not increase the likelihood of ;
j an accident since these events are independent of this change. The i j proposed activity will not change, degrade or prevent actions or alter any assumptions previously made in evaluating the radiological consequences of an accident described in the SAR. Therefore, the
, proposed amendment does not result in any increase in the probability or consequences of an accident previously evaluated.
- 2) The proposed license amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.
This change does not alter the performance of the pressure and differential pressure transmitters and switches used in the plant protection systems. All sensors will still have response time verified j by test before placing the sensor in operational service and after any maintenance that could affect response time. Changing the method of periodically verifying instrument response for certain sensors (assuring equipment operability) from time response testing to calibration and channel checks will not create any new accident initiators or scenarios.
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Revision Page 5 of 5 Periodic surveillance of these instruments will detect significant degradation in the sensor response characteristic. Implementation of the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3) The proposed license amendment does not involve a significant reduction in margin of safety.
. This change does not affect the total system response time assmmed in the safety analysis. The periodic system response time verification method for selected pressure and differential pressure sensors is
'* modified to allow use of actual test data or engineering data. The method of verification still provides assurance that the total system response is within that defined in the safety analysis, since calibration tests will detect any degradation which might significantly affect sensor response time. Based on the above, it is concluded that the proposed license amendment request does not result in a reduction in margin with respect to plant safety.
CONCLUSION Based on the preceding analysis, it is concluded that elimination of periodic sensor response time testing is acceptable and the proposed license amendment does not involve a Significant Hazards Consideration Finding as defined in 10 CFR 50.92.
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