ML20209H308
| ML20209H308 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 06/01/1999 |
| From: | Stewart M HOUSTON LIGHTING & POWER CO. |
| To: | |
| Shared Package | |
| ML20209H296 | List: |
| References | |
| 0PGP04-ZA-0604, PGP4-ZA-604, NUDOCS 9907200185 | |
| Download: ML20209H308 (10) | |
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l SOUTII TEXAS PROJECT ELECTRIC GENERATING STATION D0527 O \% P4M LC 'IIVJ'tsPuw WMsoo4 ujX ur-i. o.. ovo'-
Pnn Tune / Date 1 $2 PM oui 4m ONP04-M-0604 R*V 3 ""8e ' f' General Probabilistic Risk Assessment Program l
Quality Non Safety-Related Usage: Available Effective Date: 06/01/99 M. A. Stewart N/A N/A Risk Managernent & Industry Relations l PREPARER TECl!NICAL USER COGNIZANT ORGANIZATION l
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Table of Contents Page i
1.0 Purpose and Scope
. . .. . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . .2 i 2.0 Definitions...... . . . . . . . . . . . . . . . . . . .... . . . . . . . . . . . . . . . . . . . . . . . . .. . .2 3.0 References .. . . .... .. . .. .. . . . . . ... .. . . . . .. ... . .. . . . .. ..2 4.0 Responsibilities.. . . . . . . . . . .. . . . . . . . . . . ...... ... . . . . . . . . . . . .3 5.0 Qualifications and Training of the PRA Team Members .. . ... . . . . . . . . . . . . . .4 6.0 Requirements.. . . .. . . . . . . . . - - - - - - . . . . . . . . . .5 l
l 9907200185 990713 PDR ADOCK 05000498 p PDR
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. l OPGP04-ZA-0604 Rev. 3 Page 2 or 10 Probabilistic Risk Assessment Program
1.0 Purpose and Scope
1.1 This procedure specifies the maintenance of the South Texas Project (STP) Probabilistic Risk Assessment (PRA) and associated administrative controls. This procedure satisfies the commitment for a "living" PRA stated in References 3.2,3.3 und 3.4. l
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2.0 Def'mitions !
2.1 Probabilistic Risk Assessment (PRA)- A method of determining the theoretical risk and
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consequences of nuclear accidents. I 2.2 Level 1 PRA - The determination of the frequency of accidents causing severe core ;
damage. l 2.3 Level 2 PRA - The determination of the magnitude and frequency of radioactive releases resulting from nuclear accidents.
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2.4 Level 3 PRA - The determination of the health effects on the public due to releases from nuclear accidents.
2.5 Probabilistic Safety Assessment (PSA)- Synonymous with Probabilistic Risk Assessment.
2.6 Reference PRA Model - An identifiable set of PRA inputs which represents the nominal plant configuratian and operating condition.
3.0 References 3.1 Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Probabilistic Safety Assessment - External Events, Docket Nos. 50-498 and 50-499, L. E. Kokajko to W. T. Cottle, Aug. 31,1993.
3.2 Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment Nos. 59 and 47 to Facility Operating License Nos. NPF-76 and NPF-80, S. C. Black to W. T. Cottle, dated Feb. 17,1994.
3.3 Individual Plant Examination (IPE) - Internal Events, South Texas Project, Units I and 2, August 28,1992 supplemented by letter dated Nov. 17,1994.
3.4 NRC Staff Evaluation of South Texas Project Individual Plant Examination (IPE), (Internal Events Only), T. Alexion to W. T. Cottle, Aug. 9,1995. )
l 3.5 OPGP05-ZE-0001,"PSA Analyses / Assessments." ,
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OPGP01-ZA-0604 Rev. 3 Page 3 of l'1 Probabilistie Risk Assessment Program 3.6 OPGP07-ZA-0014," Software Quality Assurance Program."
3.7 Risk and Reliability Analysis Section (RRA) Risk Assessment Guidelines (RAGS).
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3.8 RRA PRA Quality Assurance (QA) Plan.
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OPGP03-ZX-0002, " Condition Reporting Process." l 3.10 OPGP01-ZA-0305,"PRA Model Maintenance and Update" 4.0 Responsibilities I 4.1 The Risk and Reliability Analysis (RRA) Administrator is responsible for maintaining the ;
Level 1 and Level 2 PRA for STP and will designate a Responsible Ann "st for each Reference PRA model. 4 i
4.2 The RRA Administrator has the following responsibilities concerning the PRA:
4.2.1 Overall responsibility for the PRA program. ;
4.2.2 Responsible for determining when a regular or as-needed update of the PRA is '
required.
4.2.3 Responsible for assignment of PRA tasks to the Responsible Analyst and for providing technical direction.
4.2.4 Overall responsibility for ensuring the technical adequacy of each PRA document (assigns qualified preparers and reviewers for PRA documentation). l 4.2.5 Provides approval of each PRA document.
4.2.6 Assures successful completion and long-term maintenance of each PRA document.
4.2.7 The Risk & Reliability Analysis Administrator's approval signature on a PRA document signifies final approval of the docurnent.
4.2.8 Assigns responsibility to control and track PRA d >cument numbers.
4.3 The Qualified Reviewer has the following responsibilities concerning the PRA:
I 4.3.1 k Performs various technical reviews of the PRA document as directed by the ;
Risk & Reliability Analysis Administrator. i l
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OPGP04-ZA-0604 Rev.3 Page 4 om Probabilistic Risk Assessment Program 4.3.2 Conducts a check of the PRA document to assure technical adequacy of the work performed by the Responsible Analyst and to provide critical comments; conducts a check of the PRA document to assure proper documentation.
4.3.3 Responsible for referring disagreements between the originator / preparer and l reviewer to the Risk & Reliability Analysis Administrator.
4.3.4 Reviews changes to the PRA document.
4.4 The Responsible Analyst for each Reference PRA Model is responsible for model updates, documentation, record keeping, and configuration control of the assigned model.
4.5 The Responsible Analyst (Preparer) has the following responsibilities concerning the PRA:
4.5.1 Responsible for performing defined PRA activities (e.g., PRA document development) in accordance with approved guidelines and/or established methods.
4.5.2 Responsible for developing and maintaining the PRA documents.
4.5.3 Shall assign a document number to the PRA document for ease of reference and tracking purposes. (The document numbers will be controlled and tracked by a person assigned by the Risk & Reliability Analysis Administrator.) This process must ba coordinated with the Record Management System (RMS) and Document Control organizations.
1 4.5.4 Ensures all updates / changes are incorporated in the PRA document.
4.5.5 Ensures that the information contained in the PRA document accurately reflects {
the physical plant and its operation or clearly identifies any deviations. j 4.5.6 Coordinates the development and maintenance of the PRA document.
l 5.0 Qualifications and Training of the PRA Team Members 5.1 The Risk & Reliability Analysis Administrator should meet the requirements as specified l by approved " Job Descriptions" 5.2 A PRA Analyst / Engineer who may perform as a " Qualified Reviewer" or a " Responsible Analyst (Preparer)" should meet the requirements as specified by approved " Job Descriptions" m-
D OPGP04-ZA-0604 Rev.3 l' age 5 or 10 Probabilistic Risk Assessment Program ,
5.3 A training program will be established that all personnel will have to meet. The Risk &
F 41ity Analysis Administrator can exempt personnel from all or portions of the i training requirements as he deems appropriate. Such exemption should be documented in writing in the person's training records.
6.0 Requirements 6.1 PRA Development 6.1.1 Each PRA document shall be prepared by the Responsible Analyst (Preparer) who is cognizant of associated plant systems and applicable analysis techniques.
6.1.2 Each PRA document may be developed by the Responsible Analyst using Risk Assessment Guidelines (RAGS), procedures, or any other guidance / guidelines accepted by the Risk & Reliability Analysis Administrator.
6.1.3 Each PRA document shall have a Cover Sheet and shall be numbered with a document control number, or as otherwise specified by specific RAGS or procedures, for ease of reference, tracking, and control purposes.
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6.1.4 The Preparer shall sign each PRA document > 1over Sheet. Signature of the Preparer on the Cover Sheet signifies that th locument was properly prepared.
Data sheets may be used to record signatures for electronic storage if record is referenced.
6.1.5 Symbols ar ccronyms used in the PRA documents shall be consistent with those used iri the controlled drawings and the Updated Final Risk Analysis Report.
6.1.6 Reference materials shall be individually listed. If no references are required, the section shall be included with the word "none."
6.1.7 Information shall be traceable. If possible, quality records such as the UFSAR, Technical Specifications, Controlled Drawings, Controlled Vendor Manuals, etc. shall be used as inputs to PRA analyses. However, as PRA is a "best-estimate" analysis, occasionally non-quality records, expert opinion, and engineeringjudgment may be used as input to PRA analyses. In all cases, the information sources shall be clearly identified. Because some of the references and sources are based on a judgment regarding applicability, the qualifications of the preparer, reviewer, and approver are important to ensure the technical quality of the document.
. l OPGP04-ZA-0604 Rev.3 page 6 or to Probabilistic Risk Assessment Program 6.2 Review and Approval 6.2.1 Each PRA document shall be reviewed by the Qualified Reviewer and approved by the Risk & Reliability Analysis Administrator.
6.2.2 The Qualified Reviewer may perform a review of each PRA document using guidance / guidelines established as references for the preparation of the documentation of the most recent model or as specified by the Risk &
Reliability Analysis Administrator.
6.2.3 The Responsible Analyst shall resolve with the Qualified Reviewer any comments regarding the PRA document.
6.2.4 The Qualified Reviewer shall sign and date the PRA document Cover Sheet signifying that the document has been properly developed (e.g., inputs have been properly stated, results support the conclusion) and checked.
6.2.5 The Qualified Reviewer shall forward each reviewed PRA document to the Risk & Reliability Analysis Administrator who shall, upon approval, sign and date the document Cover Sheet.
6.2.6 Each PRA document shall be re-reviewed by the Qualified Reviewer and re-approved by the Risk & Reliability Analysis Administrator if the contents are altered (e.g., following updates) such that the intent or results are impacted.
6.2.7 The results and insights from any PRA update shall be reviewed by the Qualified Reviewer and approved by the Risk & Reliability Analysis Administrator.
6.2.8 Records of review comments and associated resolutions that are technical in nature and result in material changes to the PRA shall be maintained for five years. Records of editorial and general formatting comments and associated resolutions that do not change the technical detail of the reviewed product need not be maintained.
6.2.9 The Preparer and Reviewer shall not be the same individual.
6.2.10 A PRA document or portions of a document may benefit from reviews performed outside the group. If such reviews are specified, written guidance will identify the scope of the review, and create a mechanism for capturing the review comments along with corresponding resolutions.
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6.3 Maintenance and Control 6.3.1 Reference PRA models that apply t e normal plant configuration are maintained. These reference models are periodically updated to keep them current with plant changes, operating data, and advances in PRA methodology.
6.3.2 The PRA consists of at least two models, based on plant operating mode:
. An at-power PRA applicable to modes 1 and 2 (Level 1 and Level 2 PRA).
A shutdown PRA covering modes 5 through core off-load (Level 1 only).
6.3.3 Additional Reference PRA Models that apply to parts of the plant or special l plant configurations are allowable.
6.3.4 For each Reference PRA Model, documentation is maintained that includes all sources ofinput data, modeling techniques, and assumptions used in the analysis. Input data includes physical description of the plant, component i dependencies, success criteria, methods of operation, and equipment operating history.
6.3.5 Documentation is organized into a formal report which includes at least the l following volumes: l
. Data collection and analysis )
. Event Trees
. System models
. Basic Event - TAGrfPNS Cross Reference
. External Events
. Spatial Interactions
. Human Factors
. Containment Analysis
. Summary of Results 6.3.6 These documents will be retained by Records Management.
6.3.7 PRA documents, letters, calculations, and memos will have a unique numbering system for document retrieval and control purposes. This process shall be carefully coordinated with the RMS and Document Control organizations.
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l OPGPO4-ZA-0604 Rev. 3 page 8 or 10 i l Probabilistic Risk Assessment Program 6.3.8 The overall PRA model results are updated every refueling cycle of Unit 1, not to exceed two years, or when the Risk & Reliability Analysis Administrator detennines (using guidance supplied by OPGP01-ZA-0305) an update is required.
I NOTE The PRA model may be used to perform case studies to support requests for procedure, technical specification, and surveillance interval changes, system configuration changes, and evaluation of safety {
related issues. However, such analyses are NOT considered " updates" of the PRA unless the changes I are actually permanently implemented.
6.3.9 The Risk & Reliability Analysis Administrator will fomi a PRA Team to accomplish the overall PRA model results update.
6.3.10 A Regular PRA Model Update will reassess PRA figures-of-merit periodically and use the most recent available performance and plant configuration data, as applicable. It will include a review of at least the following to determine which of these can be incorporated into the PRA:
Changes in the plant design or procedures that may affect the PRA model; e Initiating events updated assessment;
- Plant failure and operational data; 1
. Recalculation of plant core damage frequency and identification of dominant severe accident sequences, if necessary.
Recalculation of plant large early release frequency and identificatica of dominant large early release frequency sequences, if necessary.
6.3.11 The Reference PRA Model is updated at least every refueling cycle of Unit 1, not to exceed two years, in accordance with OPGP01-ZA-0305, incorporatirig applicable plant modifications, procedure changes and data collected since the previous update. All relevant documentation is updated when the reference model is updated, and the new version is not used until the model is approved and the documentation is complete. Res isions can be made more frequently at the discretion of the RRA Administrator. A file of proposed model changes will be maintained between major model updates. All probabilistic risk assessments and analyses will be performed using the latest version of the Reference PRA Model that exists at the start of the work.
OPGP0&ZA-0604 Rev.3 Page 9 or 10 Probabilistic Risk Assessment Program 6.3.12 If any changes to a PRA document are made, the Responsible Analyst must issue a new version of that document reflecting those changes. The revised i document shall be reviewed by the Qualified Reviewer and c,. proved by the
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Risk & Reliability Analysis Administrator. Upon review and approval, the document will be signed off by the Qualified Reviewer and the Risk &
Reliability Analysis Administrator.
l 6.3.13 l Old revisions of the PRA documents should be retained for five years.
6.3.14 Draft computer files created as part of each PRA document development shall be named at the discretion of the file creator (e.g., the Responsible Analyst). {
4 Final archive computer files for formal PRA documents shall be named in '
accordance with a standard format as directed by the Risk & Reliability Analysis Administrator.
6.3.15 Each computer file shall be stored on the STPEGS local area network (LAN) by the Responsible Analyst in standard directories, established and named for this purpose by the Risk & Reliability Analysis Administrator.
6.3.16 Copies of computer files and software used to obtain the PRA results shall be maintained on the LAN. Computer codes are maintained in accordance with OPGP07-ZA-0014," Software Quality Assurance Program".
6.3.17 Any changes in the base computer model input files and output files must be reviewed by a Qualified Reviewer and approved by the Risk & Reliability Analysis A dministrator, and stored on the LAN as the Updated PRA Computer Model.
6.3.18 Each update cycle, the Updated PRA (including the Updated PRA Computer Model) is documented as " complete" via a signed letter from the Risk and Reliability Analysis Administrator to RMS. Computer codes are maintained in accordance with OPOP07-ZA-0014," Software Quality Assurance Program" 6.3.19 The PRA upcates and documentation are independently reviewed and approved by the RRA Administrator. Analyses and assessments based on the PRA are performed in accordance with OPGP05-ZE-0001, "PSA Analyses / Assessments".
6.3.20 Where appropriate, quantitative and/or qualitative acceptance criteria will be identified by reference to indr try documents, or other information sources specified by the RRA Administrator.
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OPGP04-ZA-0604 Rev.3 Pau lo ofl0 Probabilistic Risk Assessment Program 6.3.21 Procurement document control for the PRA is applicable to the procurement of I consulting services and, in specified cases, to procurement of special software.
The RRA will procure services and software using standard company procurement procedures, and software will be handled and classified in accordance with OPGP05-ZA-0014.
6.3.22 Control of purchased material, equipment, and services for support of the PRA will be performed and controlled using standard company procedures and the guidance specified in IUWs Risk Assessment Guideline (RAG) 005.
6.3.23 The identification of conditions adverse to PRA quality are documented, reported to appropriate levels of management, and dispositioned via the STP plant Condition Reporting (CR) Process specified in OPGP03-ZX-0002 and via guidance provided in OPGP-ZA-0305.
6.3.24 The STP Quality Organization will provide oversight to ensure the quality of the STP PRA process including the PRA model and associated data and documentation.
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