ML19317F758
| ML19317F758 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/26/1973 |
| From: | Schwencer A US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Sampson G TOLEDO EDISON CO. |
| References | |
| NUDOCS 8001280688 | |
| Download: ML19317F758 (5) | |
Text
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CEC 2 61973 eket No. 50-346 The Toledo Edison Company D@@f i
ATT:i: Mr. Glenn J. Sampson g
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Vice President, Power 300 Ediscu Plaza
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Toledo, Ohio 43652 V(j p
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Centlemen:
By our letter to you dated August 28, 1973, we requested additional information required for our review of your application for a license to operate the Davis-Desse Nuclear Station. At that time thero vere several areas of the Davis-Eesse Final Safety Analysia Report which were incomplete to the extent that we could not complete our first round review in those areas. Specifically, infor=ation regarding the Emergency Core Cooling System, Reactor Design and Loss-of-Coolant Accident Analysis was not available.
Amendment No.16 to your application, dated October 4,1973, provided additional information in the above areas. We have emined this information l
and have identified our need for further information in the enclosure to this letter.
You will note in the enclosure to our Nevenber 23, 1973 schedulo letter to you that in order to maintcin the present review schedule, cocplete and adequate response to all first round requests must be made by July 5, 1974. If you cannot meet this date it is likely that the overall schedule for completing the licensing review for the project will have to be extended.
s Please contact us if you have any questions regarding the information requested.
Sincerely, Original S;;ned A. Schwencer, Chief Light Water Reactors Br. No. 2-3 Directorate of Licensing
Enclosure:
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OG 26E 2-Glenn J. Sampac.
Enclosure:
Request for Additional Infornation cct Donald H. Hauser, Esquire The Cleveland Electric Illuminating Co.
P. O. Box 5000, Room 610 Cleveland, Ohio 44101 Lesli "enry, Esquire Fuller, Seney, Henry & Hodge 800 Owens-Illinois Bldg.
405 Madison Avenue Toledo, Ohio 43604 Gerald Charnoff, Esquire Shav, Pittman, Potts, Trowbridge &
Madden 910 - 17th S t., NW Washington, D. C.
20006 Mrs. Evelyn Stebbins, Chair =an Coalition for Safe Electric Power 312 Park Building 140 Public Square Cleveland, Chio 44114 DISTRIBUTION:
AEC PDR Local PDR Docket LWR Rdg VAMoore JHendrie AKenneke RWKlecker OGC R0 (3)
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ACRS (16)
U JPanzarella 5 extra copies LWR A-3 L:8'R 2-J IAPelIiYr:kmL AScdidincer 12/ 3 0 /73 12/ $.,h /73 n Asc.noias un Ascas os e c4.
...........n
ENCLOSURE REOUESTS FOR ADDITIONAL INFORMATION TCLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION DOCKET No. 50-346 General Co==ent:
A=enduent 16 to the Davis-Besse application provided a nu=ber of FSAR revisions in the area of LOCA analysis and ECCS design. We note that the LOCA analysis is not cocplete. You provided an analysis of one large break in accordance with present ECCS perfor=ance criteria and indicated that other large break analyses will be provided to the revised AEC Acceptance Criteria at a lat o date.
Wa find this approach acceptable. We further note that certain portions ot the analyses presented are inconsistent with referenced B&W topical reports or other SAR's for B&W systems. Therefore, we view the LCCA analysis as an open ites in the application pending adoption of the new ECCS rules. Should the new rules not be published within the near future then we will require a co=plete ECCS analysis using the current Interim Acceptance Criteria.
Infornation with regard to the analyses of small pipe breaks has yet to be submitted by you (BAW-10075) and we will be unable to complete our first round review without this information.
Reouests:
3.9 Mechanical Systees and Cocoonenrs 3.9.7 Provide the internal vent valve design bases.
4.2 Mechanical Design 4.2.7 In addition to request 3.9.7, include comparisons of significant sizing parameters for both a greater and a lesser nu=ber of vent valves.
Justify the apparent decrease in vent valve venting area from previous design proposals (5.27 square feet for North Anna Units 3 and 4 versus 3.69 squara feet for Davis-Besse). Provide the vent valve K-factor.
Describe the vent val"1 design differences between Davis-Besse and the
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Oconee class reactors.
4.2.8 Discuss the potential for ther:al expansion of critical vent valve com-ponents causing binding during nor=al operation and during a loss-of-coolant accident. Describe aspects of the vent valve tests discussed on page 4-20g which support your evaluation with regard to ther=al binding.
With regard to the internal vent valve vibration test on page 4-20h, discuss the potential variation in vibratory response at operating temperatures.
Relate test vibration frequencies to expected reactor coolant pump vibration frequencies. If it exists, describe operating data available from Oconee with regard to vibration frequencies.
4.2.9 Provide a diagram labeling such vent valve components as the jackscrews, internally splined mating nut rings, nut ring springs, capture cover, cover attachment fasteners, hinge shaft, shaf t journals, disc journal
, receptacles, and valve body journal receptacles. Identify the various captured-design f eatures in the diagram and describe the means by which each feature fulfills its capture concept. Clarify the function of the jackscrew.
4.2.10 Review the minor proble=s which were referred to at the bottom of page 4-20b as being encountered during prototype vent valve handling or use.
Describe the corrections employed before arriving at the final design.
a.2.11 With regard to LOCA vent valve i= pact loads on tha reactor vessel wall, page 4-20d states that analysis results indicate that while the stainless steel-cladding would be defor=ed locally, the reactor would maintain its structural and pressure boundary integrity.
Evaluate the potential for, and eff ects of, pressure pulses inducing a repetitious opening and closing of the vent valves, thereby i= posing a nu=ber of localized i= pact loads upon the reactor vessel wall. Should such loads be feasible, evaluate vessel integrity in terms of strcases imposed and compare to stresses allowed. Consider the presence of such pressure pulses for all events in Chapter 15 of the FSAR.
4.4 Thermal Hydraulic Desien i
4.4.3 Page 4-20c states that the vent valves will be held closed during nor=al operation. Describe their condition during a spuriour scram transient, and during a nor=al start =p or shutdown. State how the core barrel vent valves were treated in the ther=al hydraulic analysis for normal operation. Give assumptions made in this regard for the analyses of accidents and transients.
It is our position that one valve less than the mini =um detectable nu=ber of stuck open vent valves should be assumed to be open in the analyses for the ther=al hydratiic design of the reactor coolant systes and cora and for all transients. Describe how detection is accomplished.
5.3 Ener2ency Core Cooling System 5.3.21 With regard to the core flooding tank line break:
a) Provide a complete description of all possible ECCS configurations during the recirculation mode for a spectrum of core flooding line break sizes. Identify flow routes and flow rates available to =ain-tain a cool core during this mode. Include a discussion of operator action necessary to ensure an adequate supply of cooled contain=ent su=p water to the reactor vessel for the small core flooding line break where only high pressure recirculation from the sump is possible.
It is our position that the crossover valves between the 'd?I and LPI systems are to be re=otely controlled from the control room.
b) Also, our position is that since it is generally desirable to minimize operator action and to minimize ECCS component reliability, the pro-
3-posed design for such B&W plants as North Anna 3 & 4, UNP-1, and Greenwood would be preferable to the design shown on FSAR Figure 6-17 with regard to low pressure flow equaliestion. Provide a thorough description of a re-design to this feature for Davis-Besse with a discussion of its design basis and an evaluation of its operating modes during normal reactor operation and af ter the accident. Show the effects on ECCS flow of the additional piping and valves. Also include analyses of flow rates available and how such flow rates will be split between the broken and the intact lines to the reactor.
l Describe all prototype testing that would be conducted or planned to confirm these flows. In additica, discuss the preoperational tests which would be planned to observe these flow splits for Davis-Besse.
6.3.22 With regard to the recirculation mode of operation after a LOCA, describe the protection afforded the single containment sump by way of location, shielding, inspection, etc. to diminish the possibility of a single event rendering long term core cooling unavailable.
15.1 General 15.1.5 Cc==ent on the effect of the vent valves on the results of the recaining postulated transients and accidents in Chapter 15.0.
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