ML20140E137
| ML20140E137 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/29/1986 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8602030186 | |
| Download: ML20140E137 (13) | |
Text
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 SN 157B Lookout Place January 29, 1986 1
Director of Nuclear Reactor Regulation Attention:
Mr. B. Youngblood, Project Director PWR Project Directorate No. 4 Division of Pressurized Water Reactors (PWR)
Licensing A U.S. Nuclear Regulatory Comission Washington, D.C.
20555
Dear Mr. Youngblood:
In the Matter of
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Docket Nos. 50-327 Tennessee Valley Authority
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50-328 By.the December 23, 1985 letter from J. W. Hufham to you, we provided a revised summary status report of TVA's compliance with 10 CFR 50.49,
" Environmental Qualification of Electrical Equipment Important to Safety for Nuclear Power Plants," dated December 1985 for the Sequoyah Nuclear Plant (SQN). As discussed with Paul Shemanski of NRC in recent telephone conversations, enclosed are revised pages to the summary status report which we understand will allow NRC to complete preparation of a safety evaluation report for SQN. We do not plan to submit any additional revisions to this report. We also understand that we will be required to submit a letter of certification, at a later date, that we are in compliance with 10 CFR 50.49.
If you have any comments or questions regarding this submittal, or if you disagree with our understanding, please call Jerry Wills at FTS 858-2683.
Very truly yours, TENNESSEE VA LEY AUTHORITY l
R. L. Gridley Manager of L ensing A ay 986 dhnAed% W#1X No'tary Public My Comission ExpiresU
~
AD -- J. KNIGHT (ltr only) fg*.EB(BALLARD) i Enclosures EICSB (ROSA) l cc: See page 2 PSB (GAMMILL)
RSB (BERLINGER) 8602030186 06012 l l FOB (BENAROYA)
PDR ADOCK 05000327 p
PDR An Equal Opportunity Employer
. Director of Nuclear Reactor Regulation January 29, 1986 cc (Enclosures):
U.S. Nuclear Regulatory Commission Region II Attn:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. Carl Stahle Sequoyah Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 Mr. Paul Shemanski Environmental Qualification Branch U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 1
i
ENCLOSURE REVISIONS TO THE
SUMMARY
STATUS REPORT FOR SEQUOYAH NUCLEAR PLANT (Please note that all of the pages provided in this enclosure have not changed. Those pages that are changed are marked by a vertical bar with the letter "R" to denote a revision. The remaining pages are being provided in order to maintain' continuity of section III.)
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III. EQ PROGRAM DESCRIPTION 1.
EQ Documentation Packages (Binder Concept)
Under TVA's program for EQ, all equipment in the scope of 10CFR50.49 is evaluated for compliance with 10CFR50.49 and that evaluation is documented in an EQ Binder.
The EQ binder is a design output document and is the auditable record demonstrating compliance with 10CFR50.49 for all 10CFR50.49 scope equipment. As such, EQ binders constitute quality information and are part of the plant records which are the licensing basis for plant operation.
EQ binders are permanent lifetime QA records. EQ binders are maintained current for each equipment type to demonstrate that the equipment is environmentally qualified for its application and that design basis safety functions can be accomplished. An equipment type refers to electrical equipment categorized by manufacturer and model(s) which is representative of all identical equipment in a plant area (s) potentially exposed to the same bounding environmental conditions during and after a design basis accident (e.g., Rosemount electronic pressure transmitters, Model 1153 Series D).
All auditable documentation which supports environmental qualification for the equipment type shall be compiled and placed in the EQ binder or referenced therein. EQ 4
binders reflect field-verified plant configuration for all 10CFR50.49 scope equipment.
Each EQ binder consists of:
1.
Title page referring to the vendor and equipment types 2.
Revision log 3.
Table of contents 4.
Open item and qualification deficiency listing 5.
Tab A - Identification of equipment comprising the equipment type 6.
Tab B - Checksheets for evaluation of environmental qualifi-cation including summary and conclusion j
7.
Tab C - Analyses and justification 8.
Tab D - Qualification documents
- 9.. Tab E - Miscellaneous documents and correspondence 10.
Tab F - Field verification data 11.
Tab G - Qualification maintenance data sheets 12.
Tab H - Vendor instruction manual 13.
Tab I - Vendor drawing for equipment 14.
Tab J - Evaluation of IE circulars, bulletins, and vendor bulletins r
1 i
EQP354.41 l
Design input documents used in preparation of EQ binders include (but are not limited to) the following:
1.
Desi fr Equipment List 2.
10CFR50.49 List 3.
Category and Operating Times Calculation 4.
Environmental Data Drawings 5.
Field Verification Data 6.
Design Calculations 7.
Vendor Test Reports, Correspondence, Drawings, Vendor Manuals, and Miscellaneous Vendor Contract Data The following paragraphs summarize the contents of each tabulated section of the EQ binder:
(1)
Tab A - Identification of Equipment Comprising Equipment Type This section identifies the equipment within the scope of 10CFR50.49 comprising the equipment type. Equipment is identified by plant ID number, manufacturer, model number, location (or room number), elevation, procurement contract number, safety function, mitigating accident, equipment category, and required operating time.
(2) Tab B - EQ Checksheets for Evaluation of Environmental Qualification Including Summary and Conclusion The " heart" of the EQ binder is Tab B, the EQ checksheet forms.
These forms provide a format for addressing all EQ considerations and documenting the qualification status of 10CFR50.49 equipment.
However, the EQ checksheet forms (Tab B of the EQ binder) are intended only as a tool to assist evaluators in performing qualification evaluations to document the qualification status of electrical equipment. This form is not intended to preclude the exercise of good engineering judgement. The EQ checksheet form is designed to cover explicitly the salient points of EQ, but is not intended to be a totally comprehensive EQ checklist.
Evaluators and reviewers are f amiliar with the criteria against which the evaluation is made. Based on a thorough understanding of the criteria, evaluators may feel justified to make defensible assumptions and engineering judgments when any EQ parameter satisfies the " intent" but not the " letter" of the criteria. All assumptions, engineering judgments, and extrapolations of data must have a sound engineering basis and be documented as part of the qualification package (i.e., the EQ binder).
In certain situations, evaluators may find it necessary to augment the EQ checksheet form.
In short, EQ is EQF354.41
(2) Tab B - EQ Checksheets for Evaluation of Environmental Qualification Including Sunmary and Conclusion (Continued) not a " cookbook" process. The individual sections in Tab B of the EQ binder (checksheet form, sections A through P) may be categorized into three basic parts. First, sections A through N present factual data pertinent to qualification.
Provisions are included in sections A through N for short comments and remarks necessary for clarification, but the primary content is technical data and facts. Second, section 0 is a checklist of questions and considerations which the evaluat'or considers.
The checklist is representative of the types of considerations that evaluators could potentially overlook, even with all of the factual data properly documented. Because the checklist cannot be totally comprehensive, evaluators must review the qualification criteria to ensure no significant consideration is overlooked. Third, section P is a summary writeup which is to include any supplemental comments, justifications, short extrapolations of data, and discussion necessary to document that all significant EQ considerations have been addressed.
The writeup is formatted so reviewers can easily ascertain the EQ checksheet sections being supplemented (e.g., each paragraph or comment might be numbered and a note referring the readar to the numbered comment would be included in the EQ checksheet section which the comment supplements). More extensive analysis and justifications (e.g., similarity analysis, aging and materials analysis, calculation of qualified life) shall be incorporated in Tab C of the EQ binder.
The overall philosophy of the three basic parts of the checksheet form is that all significant EQ questions and considerations must be addressed.
If a significant EQ-related consideration is not a concern, the evaluator will still document the basis for this conclusion.
(3) Tab C - Analyses and Justification This section contains data, calculations, and justifications that establish a qualified life for the equipment and present rationale to support elements which serve to establish qualification. All data in this section is cross-referenced to the applicable section of the EQ checksheets in Tab B.
(4) Tab D - Qualification Documents This section contains vendor qualification documents used to establish qualification such as test reports, analyses, and test plans.
(5) Tab E - Miscellaneous Documents and Correspondence This section contains all pertinent reference documents, miscellaneous technical data, and correspondence relating to the qualification of the equipment type.
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(6) Tab F - Field Verification Data This section includes all field verification information (such as manuf acturer, model number, location, mounting, and nameplate data) pertaining to the installed equipment.
(7) Tab G - Qualification Maintenance Data Sheets This section contains the qualification maintenance data sheet (s) (QMDS) for the equipment items identified in Tab A.
The QMDS serves a dual function in the specific environmental qualification-related maintenance requirements are identified and, if appropriate, surveillance and preventative maintenance activities are recommended based on engineering judgment and a review of documentation pertaining to the equipment. The QMDS addresses:
1.
Essential Requirements -
This section of the QMDS establishas the requirements and schedule to be used for environmental qualification-related maintenance and equipment or component replacement. These requirements are essential to maintaining the environmental qualification of the equipment on a continuing basis.
Requirements generally deal with critical test program details, special storage considerations. essential vendor instructions, identification of essential equipment interfaces, maintenance intervals, equipment or component replacement intervals (i.e., qualified life), and identification of certain hardware and material considerations. Documented information based upon plant operating and maintenance experience is also incorporated into this section when judged to be appropriate.
2.
Recommended Surveillance Parameters and Preventative Maintenance Activities -
a.
Surveillance parameters which are judged to aid in detecting degrading materials or equipment performance.
These surveillance parameters have been identified by review of the qualification documentation, evaluation of degrading mechanisms, and by the use of engineering judgment.
b.
Preventative maintenance activities and good practices for maintaining the equipment is based upon review of the vendor documentation and industry experience.
Documented information based on plant operating experience is also incorporated in this section when judged to be appropriate.
The recommended surveillance parameters and preventative maintenance activities in and of themselves are not essential environmental qualification related activities; however, it is recognized that these activities are important in establishing EQP354.41
(7) Tab G - Qualification Maintenance Data Sheets (Continued) equipment operatibility and ensuring proper equipment performance and must be considered within the context of an overall maintenance program.
(8) Tab H - Vendor Instruction Manual This section contains the latest relevant vendor instruction manual (or cover sheet and appropriate sections) which would assist in the installation and maintenance of the subject equipment. Parts list and bill of materials, where available and needed, are included in this section.
(9) Tab I - Vendor Drawing for Equipment This section contains relevant drawings (such as equipment outline drawings and installation drawings) of the equipment which would assist in providing technical information and data concerning the equipment.
(10)
Tab J - Evaluation of NCR IE Circulars, Bulletins, and Vendor Bulletins This section includes any relevant IE circulars, bulletins, notices, and vendor bulletins which are applicable to the equipment type. The resolution and disposition of the responses are also included.
III.2 Methodology for Establishing the 10CFR50.49 List III.2.a Design Basis Events - 10CFR50.49 (b)(1)
Design Basis Events (DBEs) for 10CFR50.49are high energy line breaks (HELBs) both inside and outside of containment and loss of coolant accident (LOCAs). Equipment in the 10CFR50.49 program was evaluated g
for the harsh environments through which it is required to function and/or not fail. These environments include flooding both inside and outside containment due to DBEs.
TVA has also evaluated other accidents in Chaptes 15 of the SQN FSAR
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which do not fit the 10CFR50.49 DBE definition as interpreted above but which have the potential to produce environments more severe than those encountered during normal operation or anticipated l
operational occurrences.
These accidents are the waste gas decay i
tank (WGDT) rupture, the fuel handling accident (FRA), and the steam generator tube rupture (SGTR).
These three events do not produce i
unusual temperature or pressure environments, and the radiation environments associated with them are not significant.
Radiation l
doses tg equipment necessary for mitigation of these events is less than 10 rads.
In summary, the 10CFR50.49 DBEs at SQN that produce harsh environments are only those events which are LOCAs, HELBs inside containment, and HELBs outside containment.
EQP354.41
III.2.b Environmental Data Drawings TVA environmental data drawings are design output documents which identify and define the conditions of all harsh zones which contain 10CFR50.49 scope equipment. These harsh zones' result from the design basis events described in paragraph III.2.a above. All environmental parameters necessary for design, procurement, and qualification of equipment in accordance with 10CFR50.49 are specified on these drawings.
These parameters include normal, abnormal, and accident values for temperature, pressure, relative humidity, radiation (expressed as-a 40-year integrated dose and an accident dose), flooding level (due to LOCA and HELB including contribution from spray), and spray chemistry. LOCA and HELB pressure, temperature, and relative humidity profiles are provided.
The environmental parameters shown on the drawings are derived from a number of supporting calculations that are referenced on the drawings and available for audit.
III.2.c Sequoyah Nuclear Plant Equipment List (SQEL)
The SQEL is a compilation for areas designated as harsh on the envircnmental data drawings, of all safety-related equipment -
10CFR50.49(b)(1), any required non-safety-related equipment -
10CFR50.49(b)(2), and any equipment added to comply with commitments to NUREG-0737 and/or NUREG-0578 for post-accident monitoring (PAM) -
10CFR50.49 (b) (3). The following outlines the method utilized to develop the SQEL:
1.
TVA safety-related equipment (designated as Class 1E) is powered from train A, B, or (S) special power (devices powered f rom either train A or B) and includes protection set instrument loops that feed the reactor protection system comprised of channels I, II III, and IV, and special post-accident monitor (PAM) equipment required by FSAR and NUREG-0737. This information was developed from cable schedules, instrument tabulations, and equipment tabulations.
2.
Harsh environment areas were identified f rom the Environmental Data Drawings described in Section III.2.b above.
3.
The Class 1E equipment which was located in a harsh environment was tabulated. The equipment location was determined using conduit and grounding drawings, local panel drawings, and limited field verification.
EQP354.41
III.2.c Sequoyah Nuclear Plant Equipment List (SQEL) (Continued)
Cables were identified for inclusion into the SQEL by the following methodology:
The first group is cables which are classified as 1E and connect to Category A or B (See Table VIII.1 for Category Definitions) safety-related equipment located in a harsh environment.
o All connection diagrams were reviewed to obtain cable numbers.
o Permanent site QA records were used to obtain' cable reel numbers and cable type by mark number.
o This information was then converted to a contract number from the SQN cable reel program.
o All of the above information was then tabulated on the SQEL.
Tha second group is cables that connect to equipment located in a mild environment but routed through a harsh environment.
o All Class 1E entries to the SQN cable schedule file were
- reviewed, o Each cable run was analyzed to determine if both ends were terminated in a mild environment as identified by the environmental drawings.
o The cable run was then traced on the conduit and grounding and cable tray node point diagrams to determine if the cable penetrated a harsh environment.
o For those cables penetrating a harsh environment the cable reel and contract numbers were obtained f rom the permanent site QA records.
All of the above information was then tabulated on the SQEL.
The compiled SQEL is issued as a quality assurance document.
As stated, the SQEL is a list of safety-related (IE) electrical equipment located in harsh environments.
The list was developed without regard to the function (s) of the 1E equipment.
Category and operating time evaluations arc provided separately for each IE device identified on the SQEL.
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III.2.c Sequoyah Nuclear Plant Equipment List (SQEL) (Continued)
These category and operating times evaluations are completed for each accident for which a device must function and include the safety function (s) for each accident, the NUREG-0588, Appendix E category for each accident, the required operating time for each category, and additional explanations as needed for the assigned categories and operating times if the safecy function information does not make the rationale clear.
The category and operating time evaluations are TVA design input documents and will be maintained along with the "10CFR50.49 List" to reflect the as-constructed plant.
Category and operating times for cables and other passive devices like junction boxes and penetrations are not assigned directly but are dictated by the category and operating times of the devices served.
III.2.d Non-Safety-Related Electrical Equipment - 10CFR50.49 (b) (2)
Non-safety-related electrical equipment exposed to harsh accident environments must not fail in a manner that can prevent safety-related electrical equipment from performing its safety function.
In response to IE Notice 79-22, non-safety-related devices were evaluated for their potential to adversely affect safety-related devices due to environmentally induced f ailures.
Flow, control and logic diagrams for all safety-related process systems were reviewed to determine all interf aces with non-safety-related equipment.
Detailed wiring diagrams were used if the nature of an interface
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was not clear from the control and logic diagrams. Each interface with non-safety-related equipment was evaluated for its potential to adversely affect safety functions.
The result of this study showed that six non-1E devices (three per unit in the RHR system) were identified that have the potential to adversely affect RHR.
A failure modes evaluation of these devices concluded that the devices would not adversely affect RHR if their cables were environmentally qualified. These cables are environmentally qualified and have been added to the appropriate binders and the "10CFRSO.49 List" to assure their continued qualification.
The evaluation also identified cases where disruptive signals could be generated, but in each case the operator has sufficient indication of the event and sufficient time to take corrective action.
EQP354.41
i A separate evaluation of the IE power system was also performed to investigate the effects of environmentally induced failures. The design basis of the 1E power system includes protective features for coordinated, selective clearing of single. random faults and overloads. Most failures of non-qualified equipment from environmental causes will occur in a random fashion. The IE power system is therefore adequately protected by its own design for most environmentally induced failures. Operation of this electrical protection was examined previously in analyses done to verify protection of primary containment electrical penetrations and in analyses done to identify associated circuits as defined for 10CFR50, Appendix R.
The protection has been shown to satisfy its design basis, g7 Submergence and spray effects may, however, cause multiple non-qualified electrical equipment and cable termination faults.
This type of fai.'ure is outside the design basis of the 1E power system. Devices and junction boxes exposed to containment spray or submergence inside containment or to submergence outside containment which are unqualified for these conditions have been identified.
The effects of multiple faults from these circuits on the ability of the 1E power systen to provide power to essential equipment have been evaluated.
Th. evaluations have concluded that innacceptable degradation of the 1E power system would not occur.
1 III.2.e Post Accident Monitoring Equipment - 10CFR50.49(b)(3)
TVA will complete environmental qualification of the applicable FSAR Class 1E designed instrumentation and the FSAR PAM Instrumentation before plant startup. For those instruments already added to the plant because of our commitment to post-TMI NUREGs (-0578 and -0737), environmental qualification will be accomplished in accordance with our NUREG responses or any extension granted with respect to the NUREG responses.
Presently for that instrumentation not considered operable or not installed but which will be complete by September 1987 because of Regulatory Guide 1.97 or post-TMI NUREG, environmental qualification will be complete at the time of installation and operability.
l EQP354.41 1
III.2.e Post Accident Monitoring Equipment - 10CFR50.49(b)(3) (Continued)
For that instrumentation that exists at the plants but was not designed as class 1E nor included in the origital PAM instrumentation set but will be category 1 Regulatory Guide 1.97 instrumentation, environmental qualification will be completed in accordance with the implementation schedule for Regulatory Guide 1.97 provided in TVA's response to Generic Letter 82-33 for the respective plant (e.g., September 2,1987, for Sequoyah).
III.2.f Emergency Operating Instruction (EOI) Interface TVA has investigated whether proper consideration of the equipment used in execution of Emergency Operating Instruction (E0I) requirements has been given in development of the 50.49 equipment scope. Of particular concern, the following was considered:
1.
Does the plant operator have at his disposal reliable instruments to identify and mitigate the consequences of DBEs?
2.
Have those instruments been marked so as to indicate their importance to the plant operator?
The NRC recognizes that all display instrumentation referenced in the emergency procedures will not necessarily be part of a utility's EQ program (reference Generic Letter No. 82-09).
The SQN EQ program and main control room instrument identification practices are consistent with this philosophy.
TVA's installed PAM indicators are specifically identified to the main control room operator. The indicators are marked either P1 or P2 which indicates the function these indicators fulfill as PAM channel 1 or PAM channel 2.
This method of marking the indicators on the main control room boards serves as the method of conveying the indicator's importance in lieu of requiring the indicators to be singled out in the plant procedures as being EQ safety-related.
These installed PAM indicators are served by instruments (e.g.,
transmitters, etc.) which are qualified to the 10CFR50.49 requi.ements. When other activities are implemented (i.e., NUREG-0700 and R.G. 1.97), instruments presently installed but not requiring specific identification and qualification may require upgrading.
TVA concludes that the post-accident monitoring (PAM) equipment which will be installed and qualified at plant restart provides the operator with the necessary information to identify and mitigate DBEs and are appropriately marked to indicate their importance.
EQP354.41
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