ML16141B239
| ML16141B239 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/01/1997 |
| From: | Labarge D NRC (Affiliation Not Assigned) |
| To: | Mccollum W DUKE POWER CO. |
| References | |
| TAC-M99352, TAC-M99353, TAC-M99531, NUDOCS 9710060028 | |
| Download: ML16141B239 (7) | |
Text
0 October 1, 1997 Mr. W. R. McCollum Vice President, Oconee Site Duke Energy Corporation P. 0. Box 1439 Seneca, SC 29679
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - AMENDMENT FOR THE HIGH PRESSURE INJECTION SYSTEM - OCONEE NUCLEAR STATION UNITS 1, 2, AND 3 (TAC NOS. M99531, M99352, AND M99353)
Dear Mr. McCollum:
By letter dated September 4, 1997, Duke Energy Corporation requested amendments to the Technical Specifications for the Oconee Nuclear Station, Units 1, 2, and 3. The proposed amendments address a potential unreviewed safety question associated with the implementation of a revised small break loss-of-coolant accident analysis to justify operation of a unit at or below 60 percent reactor power with two of the three high pressure injection system pumps operable.
In order to process the proposed amendments further, we have determined that additional information is needed, as explained in the enclosure.
Sincerely, ORIGINAL SIGNED BY:
David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/encl: See next page Distribution:
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DLaBarge JJohnson, RII BBoger TCollins COgle, RII To receive a copy of this document, indicate in the box:
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OFFICE P
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SRubin (Q11-22) HBieVw DATE
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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 October 1, 1997 Mr. W. R. McCollum Vice President, Oconee Site Duke Energy Corporation P. 0. Box 1439 Seneca, SC 29679.
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION - AMENDMENT FOR THE HIGH PRESSURE INJECTION SYSTEM - OCONEE NUCLEAR STATION UNITS 1, 2, AND 3 (TAC NOS. M99531, M99352, AND M99353)
Dear Mr. McCollum:
By letter dated September 4, 1997, Duke Energy Corporation requested amendments to the Technical Specifications for the Oconee Nuclear Station, Units 1, 2, and 3. The proposed amendments address a potential unreviewed safety question associated with the implementation of a revised small break loss-of-coolant accident analysis to justify operation of a unit at or below 60 percent reactor power with two of the three high pressure injection system pumps operable.
In order to process the proposed amendments further, we have determined that additional information is needed, as explained in the enclosure.
Sincerely, David E. LaBarge, Senior Project Manager Project Directorate 11-2 Division of Reactor Projects - 1/11 Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287
Enclosure:
Request for Additional Information cc w/encl: See next page
Oconee Nuclear Station cc:
Mr. Paul R. Newton Mr. J. E. Burchfield Legal Department (PBO5E)
Duke Energy Corporation 422 South Church Street Oconee Nuclear Site Charlotte, North Carolina 28242 P. 0. Box 1439 Seneca, South Carolina 29679 J. Michael McGarry, III, Esquire Winston and Strawn Ms. Karen E. Long 1400 L Street, NW.
Assistant Attorney General Washington, DC 20005 North Carolina Department of Justice Mr. Robert B. Borsum P. 0. Box 629 Framatome Technologies Raleigh, North Carolina 27602 Suite 525 1700 Rockville Pike Mr. G. A. Copp Rockville, Maryland 20852-1631 Licensing - ECO50 Duke Energy Corporation Manager, LIS 526 South Church Street NUS Corporation Charlotte, North Carolina 28242-0001 2650 McCormick Drive, 3rd Floor Clearwater, Florida 34619-1035 Mr. Richard M. Fry, Director Division of Radiation Protection Senior Resident Inspector North Carolina Department of U. S. Nuclear Regulatory Environment, Health, and Commission Natural Resources 7812B Rochester Highway 3825 Barrett Drive Seneca, South Carolina 29672 Raleigh, North Carolina 27609-7721 Regional 'Administrator, Region II U. S. Nuclear Regulatory Commission Atlanta Federal Center 61 Forsyth Street, S.W., Suite 23T85 Atlanta, Georgia 30303 Max Batavia, Chief Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201 County Supervisor of Oconee County WaShalla, South Carolina 29621
REQUEST FOR ADDITIONAL INFORMATION HIGH PRESSURE INJECTION SYSTEM Questions from Reactor Systems Branch
- 1.
The manual atmospheric dump valves (ADVs) are credited in the loss-of-coolant accident (LOCA) analysis, and as a result, should be included in the technical specifications. Controlling the operability requirements in a license commitment is not sufficient. The failures of these valves in the context of a single failure analysis should also be described. The modeling of these valves needs to be described and linked to the operability requirements in the technical specifications (TS). If the accident analysis models two of two valves, then the inoperability of one valve puts the plant beyond design basis and the allowed outage time (AOT) should be very short. The AOT should be consistent with the AOT associated with the high pressure injection (HPI) system.
Use of specifications similar to those in the standard TS is not appropriate because the standard TS do not consider the use of the ADVs to function to mitigate the consequences of a LOCA.
- 2.
Discuss the safety and seismic classification of the ADVs, the other valves needed for the ADVs to function (the block, throttle, isolation, and small pressure equalization valve), and the down stream piping. If they are not safety-related or seismic, explain why they are not needed to be and why they will be available following a design basis accident. The explanation should include a discussion of why this change will not violate the plant licensing basis, the applicable regulations, the applicable design criteria, and the applicable regulatory guidance.
- 3.
The new accident analysis using the new LOCA methodology, BAW-10192P-A, should be described in some detail with explicit explanation of how the use of the methodology is in conformance with the code restrictions and limitations. All of the emergency core cooling system acceptance criteria should be discussed in the submittal (not just the peak centerline temperature). Additionally, a discussion of the spectrum of breaks that were analyzed for both one HPI and two HPI operation should be described in detail.
The limiting break for each case should be identified with a justification provided that includes a technical discussion that the limiting break has been identified and analyzed (please pay particular attention to the HPI injection line break). The single failures chosen should be described and justified for the different scenarios (one pump operation, two pump operation, etc.) and a description of the assumptions associated with loss of offsite power and reactor coolant pump operation should be provided. Using the results of the old and new analysis, try to estimate the margin or benefit gained by applying the new code.
- 4.
To be clear what methodologies are being used for which LOCA applications, please provide a table and indicate what methodologies are being used for large breaks (with the sizes) and small breaks (with sizes and locations) and reference them in the TS.
Verify that the Core Operating Limit Report references or the TS administrative controls references do not need to be changed with the change in the LOCA methodology.
-2
- 5.
You explain that the "HPI injection nozzle is not included in the break spectrum" in your submittal. Please provide greater detail and a drawing of what is and is not included in the break spectrum and then describe what break sizes and types are analyzed.
- 6.
Figures 15.28, 15.29, and 15.30 of the Final Safety Analysis Report (FSAR) show injected flow for two pump operation. Please include the total pump flow in this table so that the flow split can be better evaluated. The calculated peak centerline temperature (PCT) is higher for one pump operation. As a result, please include tables representing the calculated flow split for one pump operation. Describe the method of calculating the flow split for the different cases.
- 7.
The FSAR Figures 4-46 and 4-49, showing the small break (SB) LOCA model interfaces and nodalization, are being removed. Rather than remove the figures, please update them with the new methodology interfaces and nodalization.
- 8.
In "Insert 4" to the FSAR, you describe two errors in the analysis methods and inputs that resulted in the calculated PCT to go up by 920F. Please describe the reanalysis performed as a result of the significant error in the original analysis. Was it performed by rerunning the computer code with the changes or were the changes evaluated to determine a A PCT? Additionally, please verify that all of the other cases that were analyzed were also performed using a model with the correct inputs.
- 9.
The proposed change to the licensing basis for Oconee would increase the equipment needed and the operator actions necessary to mitigate a spectrum of SBLOCAs. To successfully mitigate the consequences of the spectrum of SBLOCAs, the equipment now needed includes the auxiliary feedwater systems and successfully depressurizing the steam generators. The operators are required to perform these actions manually along with a number of others. With more equipment needed and more operator actions necessary, there is a greater chance of equipment failure and operator failure. As a result, please quantify the increased risk as a result of relying on additional equipment and putting a greater burden on the operators.
- 10.
While reviewing your original submittal (March 31, 1997), we discovered an apparent inconsistency in the licensing basis that does not appear to affect the unreviewed safety question. That submittal is requesting a change to the licensing basis to redefine the function of the HPI system and state that it is not required for long-term cooling. The current licensing basis for the system, as stated in the current TS Bases on page 3.3-6, is that the HPI system is required for long-term cooling. Page 10 of the March 31 submittal states that, "systems required for long term core cooling are required to withstand passive failures." As a result, according to the current licensing basis, the HPI system should be able to withstand passive failures. We have not performed an in-depth review of the system (we are planning to in January following the system reliability study); however, a quick look at the system indicates that with the suction of
-3 the three pumps cross connected, the system does not appear to be passive failure proof. Additionally, from the discussion in the submittal, it appears that Duke Energy may not consider the need for the system to be passive failure proof. Please address this apparent noncompliance in the current licensing basis.
- 11.
Describe the steps and times associated with briefing the operator(s) and ultimately taking manual operator action(s) to realign HPI within 10 minutes.
- 12.
Provide the demonstrated times for operators that would be expected to complete the manual action(s) to realign HPI.
- 13.
Discuss operator training that is necessary to carry out the manual operator actions, including any operator qualifications required to carry out these actions.
- 14.
Provide the results of a sensitivity study that would evaluate the significance of demonstrated response times that exceed the assumed response time of 10 minutes to realign HPI.
- 15.
Provide a description of the information needed by the control room staff to determine if there is a need to realign HPI.
- 16.
Provide a copy of the sections of the procedures that are relevant to the manual operator action(s).
- 17.
Describe how operator(s) become aware that there is a need for manual action?
- 18.
Discuss how many operators will perform the manual action?
- 19.
ANSI-58.8 supplies estimates of reasonable response times for operators, but does allow licensees to use time intervals derived from independent sources, provided they are based on task analyses with consideration given to human performance. Discuss whether ANSI-58.8 has been considered in determining the times for manual operator action.
- 20.
Discuss the following relative to the proposed manual operator action(s):
- a.
Potentially harsh or inhospitable environmental conditions,
- b. Ingress/egress paths taken by the operator(s) to perform functions, and
- c.
Additional support personnel and equipment required by the operator to carry out actions.
-4
- 21.
Describe the information required by the control room staff to determine that such operator action is required, including qualified instrumentation used to diagnose the situation and to verify that the required action has been successfully taken.
- 22.
Discuss the ability to recover from plausible errors in performance of manual actions and the expected time required to make such a recovery.