ML20247D447

Forwards Request for Addl Info Re NUSCO-163, Haddam Neck Plant Small Break LOCA Analysis Zircaloy Clad Fuel

ML20247D447
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	07/18/1989
From:	Wang A Office of Nuclear Reactor Regulation
To:	Mroczka E CONNECTICUT YANKEE ATOMIC POWER CO.
References
NUDOCS 8907250197
Download: ML20247D447 (5)

Text

.

July 18, 1989 j L

Docket.No. 50-213 DISTR *BUTION

. . TsfDoctet:t1le; EJordan j Mr. Edward J. Mroczka, Senior Vice President NRC & Local PDRs BGrimes Nuclear Engineering and Operations Plant File ACRS(10) i Connecticut Yankee Atomic Power Company SVarga ,

Northeast Nuclear Energy Company BBoger i P.O. Box 270 SNorris -1 Hartford, Connecticut 06141-0270 AWang_ {

OGC Dear Mr.' Mroczka l

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING NORTHEAST UTILITIES' TOPICAL REPORT NUSCO-163, "Haddam Neck Plant Small Break LOCA-Analysis Zircaloy Clad Fuel" .

The NRC staff has reviewed Topical, Report NUSCO-163 and has' determined that additional information is needed to complete our safety evaluation. Enclosed are our questions regarding this topical report.

The reporting and/or recordkeeping. requirements contained in this letter affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511. l If you have any questions or comments please contact me at'(301) 492-1313.

Sincerely. -!

/s/

Alan B. Wang, Project Manager Project Directorate I-4 '

Division of Reactor Projects I/II Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/ enclosure:

See next page

[SMALLBREAKLOCA]

LA:PD yI- PM:PDI-gb PD: 44 SN is AWang:cb JSto 7/ 89 7/ lr/89 7/f/

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8907250197 890718 3 PDR ADOCK 05000213 P PDC j

,. July 18, 1989 Docket No. 50-213 DISTRIBUTION Docket File EJordan

• Mr Edward J. Mroczka, Senior Vice President NRC & Local PDRs BGrimes Nuclear Engineering and Operations Plant File- ACRS(10)

Connecticut Yankee Atomic Power Company SVarga Northeast Nuclear Energy Company BBoger '

P.O. Box 270 SNorris Hartford, Connecticut 06141-0270 AWang OGC Dear Mr. Mroczka

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION REGARDING NORTHEAST UTILITIES'  ;

l TOPICAL REPORT NUSCO-163, "Haddam Neck Plant Small Pisak LOCA '

Analysis Zircaloy Clad Fuel" The NRC staff has reviewed Topical Report HUSCO-163 and has determined that additional information is needed to co.nplete our safety evaluation. Enclosed  ;

are our questions regarding this topical report.

The ieporting and/or recordkeeping requirements contained in thir letter I affect fewer than ten respondents; therefore, OMB clearance is not required  ;

under P.L.'96-511. 1 If you have any questions or comments please contact me at (301) 492-1313.

Sincerely,

/s/ i Alan B. Wang, Project Manager i Project Directorate I-4 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation

Enclosure:

As stated cc w/ enclosure:

See next page

[St1ALL BREAK LOCA)

LA:PDI- PM:PDI-gi.'"' PD: 44 SN s AWang:cb JStot 7/l 89 7/ N/89 7/ f /

.. Mr. Edward J. Mrotzka Connecticut Yankee Atomic Power Company Haddam Neck Plant CC:

Gerald Garfield, Esquire R. M. Kacich, Manager I

Day, Berry and Howard Generatior. Facilities Licensing Counselors at Law Northeast Utilities Service Company City Place Post Office Box 270 Hartford, Connecticut 06103-3499 Hartford, Connecticut 06141-0270 W. D. Romberg, Vice President D. O. Nordquist Nuclear Operations Director of Quality Services Northeast Utilities Service Company Northeast Nuclear Energy Company Post Office Box 270 Post Office Box 270 Hartford, Connecticut 06141-0270 Hartford, Connecticut 06141-0270 Kevin McCarthy, Director Regional Administrator l Radiation Control Unit Region I Depsrtment of Environmental Protection U. S. Nuclear Regulatory Commission State Office Building 475 Allendale Road Hartford, Connecticut 06106 King of Prussia, Pennsylvania 19406 Bradford S. Chase, Under Secretary Board of Selectmen Energy Division Town Hall Office of Policy and Management Haddam, Connecticut 06103 80 Washington Street Hartford, Connecticut 06106 J. T. Shediosky, Resident Inspector Haddam Neck Plant D. B. Miller, Station Superintendent c/o U. S. Nuclear Regulatory Commissior Haddam Neck Plant Post Office Box 116 Connecticut Yankee Atomic Power Company East Haddam Post Office RFD 1, Post Office Box 127E East Haddam, Connecticut 06423 l East Hampton, Connecticut 06A24 G. H. Bouchard, Unit Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 l

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ENCLOSURE REQUEST FOR ADDITIONAL INFORMATION ON 1 1

NUSCO 163 SMALL BREAK LOCA ANALYSIS ZIRCALOY CLAD-FUEL l

HADDAM NECK P'. ANT

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1. NUREG-0630 provides. infomation regarding the zircaloy-clad material and 1 deformation behavior for use in ECCS licensing analyses. Demonstrate that +" 'ad behavioral model in NULAP5 is consistent with or j consert '

3.y bounds the data in NUREG-0630. <

2. Explain why the initial portion of the power transients for the stainless f steel-clad fuel (of the previous analysis) results in a higher _ overpower f

than that for the zircaloy-clad fuel.  !

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3. What are the limiting time-of-life fuel parameters for use in initializing i the hot rod for small break LOCA enslyses? If the fuel rod cladding temperatures could achieve rupture conditions, would end-of-life '

conditions (when pin pressure is at a maximum) be more limiting than i early in life when the stored energy is at a maximum?

4. Explain why the limiting break areas are significantly different for the-stainless steel-clad and zircaloy-clad fuels? What.effect did the change in critical flow modeling have on the limiting break size? In addition, justify why additional break sizes between .02 and .075 sq. ft. were not 1 analyzed to ensure the determination of the maximum peak clad temperature

) for a small break LOCA.

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5. The clad surface temperature for the .01 sq. ft break shows an increasing trend to 2,000 seconds. Explain why the transient was not extended past 2,000 seconds to ensure that'the clad surface temperature had peaked.

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6. Please supply plots of the hot rod channel steam temperatures and saturation temperatwes for each of the breaks.

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7. By letter dated August 3,1988, the staff provided a safety evaluation of l the use of the NULAP5 code. Conclusion 7 of the evaluation stated that the licensee committed to review the core thermal-hydraulics and clad l -

temperature response in all future calculations to ensure that the clad temprature increase is not artificially terminated By the existence of fnist flow in the upper core during the loop seal clearing uncovering period. Provide evidence of this review.

8. With regard to figures A.15 through F.15, define two-phase level and d cuss its use as part of your evaluation methodology. We have also noticed a possible inconsistency in the relation between the two-phase level and tne collapsed liquid level. Specifically, in Figut* f.15, an initial depression of the two-phase level occurs when the collapsed liquid level shows a significant increase. Also in Figure F.15 at the end of the transient, the two-phase level is about 90% and the liquid mass is less than 5%, while earlier, at about 90 seconds, the liquid mass is about 25% with a corresponding two-phase level of about 55%. Please explain in detail the relation between the two-phase level and collapsed water level indicated in this Figure as well as Figures A thru F.15.  ;

9. What causes the clad temperature increase in Figure E.14 when the core is covered with two-phase flow?

10. Explain the large oscillations in the two-phase level in Figure F.15. l l

12. The heat transfer coefficient in Figures P4 is difficult to interpret at values below 500 Btu /hr/sq. ft./F. Please provide an additional plot or tabulated data (0-500) so that the variation of the heat transfer coefficient for the latter portion of the transient, particularly when '

steam cooling governs the heatup of the hot rod, may be reviewed.

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