ML20035G529
| ML20035G529 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 04/22/1993 |
| From: | Martin R Office of Nuclear Reactor Regulation |
| To: | Tuckman M DUKE POWER CO. |
| References | |
| TAC-M74394, NUDOCS 9304280046 | |
| Download: ML20035G529 (5) | |
Text
April 22,1993 8
Docket Hos.
50-413 and 50-414 Mr. M. S. Tuckman Vice President, Catawba Site Duke Power Company 4800 Concord Road York, South Carolina 29745
Dear Mr. Tuckman:
SUBJECT:
REVIEW 0F CATAWBA INDIVIDUAL PLANT EXAMINATION SUBMITTAL (TAC NOS. M74394 AND M75395) i The NRC staff has initiated its review of the Individual Plant Examination submitted on September 10, 1992, for the Catawba Station. We have identified a need for additional information as addressed in the enclosure. We request that responses be provided to these items within sixty (60) days of your l
receipt of this letter.
This requirement affects fewer than 10 respondents and, therefore, it is not subject to Office of Management & Budget review under P. L.96-511.
Sincerely,
/s/
Robert E. Martin, Senior Project Manager Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
Questions on Catawba IPE Submittal cc w/ enclosure:
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f April 22, 1993 Docket Nos.
50-413 l
and 50-414 i
Mr. M. S. Tuckman Vice President, Catawba Site Duke Power Company 4800 Concord Road York, South Carolina 29745
Dear Mr. Tuckman:
l
SUBJECT:
REVIEW 0F CATAWBA INDIVIDUAL PLANT EXAMINATION SUBMITTAL (TAC NOS. M74394 AND M75395) l The NRC staff has initiated its review of the Individual Elant Examination submitted on September.10, 1992, for the Catawba Station. We have identified a need for additional information as addressed in the enclosure. 'We request i
that responses be provided to these items within sixty (60) days of your j
receipt of this letter.
~
This requirement affects fewer than 10 respondents and, therefore, it is not j
subject to Office of Management & Budget review under P. L.96-511.
j i
Sincerely, A W Ak #
Robert E. Martin, Senior Project Manager Project Directorate 11-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
Questions on Catawba IPE Submittal
'cc w/ enclosure:
E See next page I
l l
Mr. M. S. Tuckman Duke Power Company Catawba Nuclear Station l
I cc:
Mr. R. C. Futrell Mr. Alan R Herdt, Chief Regulatory Compliance Manager Project Branch #3 Duke Power Company U. S. Nuclear Regulatory Commission 4800 Concord Road 101 Marietta Street, NW. Suite 2900 York, South Carc'ina 29745 Atlanta, Georgia 30323 Mr. A. V. Carr, Esquire North Carolina Electric Membership 1
Duke Power Company Corporation 422 South Church Street P. O. Box 27306 Charlotte, North Carolina 28242-0001 Raleigh, North Carolina 27611 J. Michael McGarry, III, Esquire Senior Resident Inspectcr
~i Winston and Strawn Route 2, Box 179 N 1400 L Street, NW York, South Carolina 29745 Washington, DC 20005
~
Regional Administrator, Region II North Carolir.a MPA-1 U. S. Nuclear Regulatory Commission Suite 600 101 Marietta Street, NW.' Suite 2900 t
P. O. Box 29513 Atlanta, Georgia 30323 Raleigh, North Carolina 27626-0513 Mr. Heyward G. Shealy, Chief Mr. T. Richard Puryear Bureau of Radiological Health 1
Nuclear Technical Services Manager South Carolina Department of Carolinas District Health and Environmental Control Westinghouse Electric Corporation 2600 Bull Street P. O. Box 32817 Columbia, South Carolina 27602 i
Charlotte, North Carolina 28232 i
Mr. G. A. Copp County Manager of York County Licensing - EC050 York County Courthouse Duke Power Company York, South Carolina 29745 P. O. Box 1006 Charlotte, North Carolina 28201-1006 Richa-d P. Wilson, Esquire Assistant Attorney General Saluda River Electric South Carolina Attorney General's P. O. Box 929 Office Laurens, South Carolina 29360 j
P. O. Box 11549 i
Columbia, South Carolina 29211 Ms. Karen E. Long i
Assistant Attorney General l
Piedmont Municipal Power Agency North Carolina Department of Justice 121 Village Drive P. O. Box 629 Greer, South Carolina 29651 Raleigh, North Carlina 27602 f
b
ENCLOSURE OVESTIONS ON CATAWBA INDIVIDUAL PLANT EXAMINATION (IPE) SUBMITTAL 1.
Given that the design and operation for the Catawba facility are essentially the same as that of the McGuire facility, provide any major
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design and operational differences (along with the differences in major assumptions) that are found to impact the frequency of major functional sequences for the above facilities (e.g., TBU sequences).
2.
Provide the following information related to the Catawba plant walkdowns performed as part of the IPE:
A.
Types of walkdowns performed B.
Objective and scope of each walkdown C.
A brief discussion of the process used to integrate findings into the plant model (for further modeling or for deciding plant fixes) 3.
Provide additional information related to the peer review process conducted for the Catawba IPE:
A.
Briefly discuss the personnel involved in the peer review B.
Activities conducted (e.g., areas of spot checks and audit calculations)
C.
Tools used (e.g., procedures and checklists)
D.
A summary of major findings made during the peer review activity and a dispositioning of these findings i
4.
Provide the version and the date of the CAFTA code used for the Catawba IPE/PRA.
Is the same version of the code used for.the Oconee and McGuire facilities? If not, please discuss any major differences (among versions) which could affect the quantification of core damage
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frequency. Your discussion should include the modeling of train level dependencies (for example, treatment of circular logic loops).
5.
The staff notes that one of the four actions taken as part of the IPE I
activity includes improvements to the Catawba training simulator.
(
Please concisely discuss these improvements and the extent to which they refocused training.
6.
DPC has decided that certain plant improvements considered as part of the turbine flood protection are not cost effective. Describe the analysis preformed, the decision process, and the results related to i
disposition of this issue.
t 7.-
Appendix G to the McGuire IPE indicates that the containment failure pressure distribution corresponds to a log normally distributed j
probtbility function with a median pressure value of 77 psig and a mean
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pressure value of 76.71 psig. Although the information presented in Appendix G of the Catawba IPE seems to indicate that the Catawba containment structure is identical to McQuire in shell thickness (3/4")
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4 and both structures are subject to the same analytical process, the Catawba structure is stronger (i.e., the containment failure pressure distribution corresponds to a log normally distributed probability function with a median pressure value of 84.5 psig and a mean value of 83.93 psig).
Please identify and discuss those differences between the two containment structures that result in the increased containment strength for Catawba.
8.
The Catawba analysis indicates that the conditional probability of early containment failure (0.005) is significantly reduced in comparison to the early containment probability (.020) for McGuire.
Please identify and discuss those factors which allow for a significant reduction in the probability of early containment failure for Catawba.
The discussion should also address the reasons for a slightly increased probability of late containment failure for Catawba.
9.
The probability of bypass failure of the containment was determined to be 0.024 at McGuire, and it was indicated that bypass failure was dordnated by induced steam generator tube ruptures (ISGTR) (over 90% of tha bypass frequency is due to ISGTR). The Catawba IPE indicates the p*obability of bypass failure is 0.002 and that it is dominated by ILLOCA.
It is our understanding that the steam generators at,both b:Guire Unit 1 (the unit analyzed for the McGuire IPE) and Catawba Unit (the unit analyzed for the Catawba IPE) are scheduled for replacement sn the near future, because of severe tube cracking.
Please identify and discuss the differences between McGuire and Catawba which provide LJch widely different insights into the containment bypass failure mode and the significance of these differences.
10.
In response to our request for additional information on the McGuire IPC, DPC indicated that a strategy for restoring hydrogen igniters in small groups, following loss of critical AC power events, is being considered for implementation in the accident management guidance.
Please indicate whether this strategy is also being considered for Catawba, and discuss the reasoning for your action with regard this potential strategy.
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