ML20094C528
| ML20094C528 | |
| Person / Time | |
|---|---|
| Issue date: | 11/24/1975 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-75-087, NUREG-75-087-15.0, NUREG-75-87, NUREG-75-87-15.0, SRP-15.00, NUDOCS 9511020251 | |
| Download: ML20094C528 (4) | |
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NUREG-75/087
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U.C. NUCLEAR RE2ULATCRY CCMMIZ13N STANDARD REVIEW PLAN i
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OFFICE OF NUCLEAR REACTOR REGULATION v
SECTION
15.0 INTRODUCTION
The Division of Technical Review branches that have responsibility for review of the postulated transients and accidents listed in this chapter are the Reactor Systems Branch (RSB), the Core Performance Branch (CPB), the Accident Analysis Branch (AAB), and the Effluent Treatment Systems Branch (ETSB).
RSB reviews analyses of the transients and accidents from the viewpoint of systems operation and performance. CPB reviews analyses of core, fuel, and thenmal-hydraulic behavior during postulated accidents. ETSB reviews analyses of postulated spills of radioactive material outside containment. AAB evaluates possible radiological consequences of the transients and accidents.
Events such as fires, floods, storms, or earthquakes are not explicitly considered in the review of postulated transients and accidents in Chapter 15. Rather, the consequences and effects of these postulated events are reviewed under other standard review plans (SRP's),
as listed in Table 15-1 (attached).
i The reviewers are responsible for the selection and emphasis of aspects of the reviews of tran-i sients and accidents in this chapter. Judgment on the areas to be given attention during each l
review is based on an inspection of the information provided, the similarity of this material to that recently reviewed on other plants, and whether items of special or unique safety signifi-1 cance are involved.
Various 1
The Reactor Systems Branch reviews nearly all the postulated transients and accidents.
anticipated process disturbances, equipment malfunctions, and postulated component failures are examined to evaluate the plant capability to control or accomodate such failures and malfunc-The RSB review includes an analysis of the pressure to which the reactor and steam tions.
systems are subjected and the need for engineered safety features to mitigate the consequences of accidents. The impact of various single failures on the course of a transient or accident is also considered. The containment and subcompartment response to postulated accidents is reviewed by the Containment Systems Branch under SRP 6.2.1.
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The Core Performance Branch is responsible for 9he review of all physics data presented in this chapter. This includes power levels, power distributions, Doppler coefficients, modarator tem-p2rature coefficients, void coefficients, reactor kinetics parameters, and control rod worths.
The CPB review includes the evaluation of possible damage to the fuel. CPB also reviews the operating bands and uncertainty bands associated with these variables and assists RSB as requested.
The review of transients and accidents by RSB requires an evaluation of results, presented in the application, of analytical methods which frequently are not documented in the application.
In such cases, the applicant may refer to a vendor topical report. The methods include DNB
-(departure from nucleate boiling) correlation development, subchannel analysis, system tran-sient analysis, artlysis of RIA (reactivity-initiated accidents), and LOCA (loss-of-coolant accident)analysi For those cases where applicants use techniques previously considered and approved by the st t f, additional review of methods may not be required. However, if new methods are involved, the CPB performs a review of topical reports and other information which describe the method of analysis. Such a review generally includes vendor model description, data corre-lations and empirical relationships, solution techniques, summary of computer codes if involved, sample problems, experimental verification, and comparative calculations.
In its review of transients and accidents, RSB may request from CPB, from time to time, an independent check of the results submitted by the applicant. In such cases CPB obtains input
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data from the applicant for use in auditing-codes available to the staff.
Upon request of RSB, the Electrical. Instrumentation and Control Systems Branch provides assistance in evaluating the sequence of postulated events, protective and safeguards systems actuation and potential bypass modes, and manual control. EICSB determines whether reactor protection and safeguards controls and instrumentation will function as assumed in the transient analysis with regard to manual or automatic actuation; remote sensing, indication, and control; onsite emergency power systems; and interlocks with auxiliary or shared systems.
The Accident Analysis Branch review is concentrated on those more severe accidents that could result in the release of radioactive materials and could have significant radiological consequences imlyig use general public. AAB determines the potential doses resulting from the accidents and compares these doses to established dose criteria and guidelines. Based on the results of these analyses AAB determines the adequacy of equipment designed to mitigate radiological consequences. In addition, radiological analyses are made to determine certain technical specification limits for safety-related equipment and structures.
15.0-2 11/24/75
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TABLE 15-1 Branches Having Primary Review or Postulated Event Standard Review Plans.
Responsibility Accidents at Nearby 2.2.3 Evaluation of Potential Accident Analysis Locations Accidents Branch Storms 2.3 Meteorology Site Analysis Branch 3.3 Wind and Tornado Loadings Structural Engineering Branch Floods 2.4 Hydrologic Engineering Site Analysis Branch 3.4 Water Level (Flood) Design Auxiliary and Power Conversion Systems Branch 7
Earthquakes 2.5 Geology and Seismology Site Analysis Branch 3.2 Classification of Struc-Reactor Systems Branch tures, Components and Systems 3.7 Seismic Design of Structural Engineering Structures Branch 3.8 Design of Category 1 Structural Engineering Structures Branch 3.10 Seismic Design of Cate-Electrical, Instrumenta-gory 1 Instrumentation tion and Control and Electrical Equipment Systems Branch Missiles 3.5 Missile Protection Accident Analysis Branch Reactor Systems Branch Auxilfary and Power Conversion Systems Branch Structural Engineering Branch Fires 9.5.1 Fire Protection System Auxiliary and Power Conversion Systems Branch l
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