ML20207H072

Forwards Response to Request for Addl Info Re License Change Application 137 Proposal to Increase Max Pressurizer Spray Differential Temp Limit of Tech Spec 3.4.9.2.c from 320 F to 560 F

ML20207H072
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	12/29/1986
From:	Lindblad W PORTLAND GENERAL ELECTRIC CO.
To:	Varga S Office of Nuclear Reactor Regulation
References
TAC-60781, NUDOCS 8701070452
Download: ML20207H072 (4)

Text

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O PORTLANn GENERAL ELECTHIC COMI%NY 121 S. W. S ALM o N STREET PORTLA N D, O R EGON 97204 WI LLIAM J. LIN DB LAD

" (603;226-8875 December 29, 1986 Trojan Nuclear Plant Docket 50-344 License NPF-1 Director of Nuclear Reactor Regulation ATTN: Mr. Steven A. Varga Director, PWR-A Project Directorate No. 3 U.S. Nuclece Regulatory Commission Washington DC 20555

Dear Mr. Varga:

TROJAN NUCLEAR PLANT License Change Application 137 Pressurizer Spray Water Differential Temperature License Change Application (LCA) 137 proposes to increase the maximum pressurizer spray differential temperature limit of Trojan Technical Specification 3.4.9.2.c from 320*F to 560*F. This change more accurately reflects the pressurizer design basis and removes an unnecessary license restriction preventing the discretionary use (within the cyclic limits of Table 5.9-1) of auxiliary spray as a means of pressure control during certain accident scenarios.

During your staff's review of the LCA, several questions were raised l

regarding material properties of the pressurizer and the effects of postulated transients. Attached are responses to those questions.

Sincerely, f,

A en AYe/ f Attachment c: Mr. David Kish, Acting Director State of Oregon Department of Energy 8701070452 861229 PDR ADOCK 05000344 /

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o Trojan Nuclear Plant Mr. Steven A. Varga Docket 50-344 December 29, 1986 License NPF-1 Attachment Page 1 of 3

. Responses to questions on Trojan's Technical Specification change increasing the maximum pressurizer spray differential temperature limit from 320*F to 560*F:

Question 1 Was fracture analysis conducted?

Response-No. The vessel was designed and originally analyzed to the ASME Code,Section III, 1968 Edition / Winter 1968 Addenda. This edition / addenda of the code did not have any requirements for the fracture mechanics analysis. A fracture analysis for the new differential temperature was not performed because the original fatigue analysis was performed for 560*F.

Ouestion 2 During the transient of injecting 100*F water into the Pressurizer, do the metal temperatures (pressurizer wall and spray nozzle) stay above the upper shelf temperature? Is a cooldown rate of 200*F/hr or less maintained?

i Resporse The appliccble code edition / addenda for this vessel did not require determinstion of RTNDT and KIR. Therefore, it cannot be established whether metal temperatures stay above the upper shelf temperature during l postulated 100*F water injection into the pressurizer. However, since the cooldown rate of the metal will lag the cooldown rate of the water, the metal temperatures are conservatively determined.

During the postulated transient, inadvertent auxiliary spray (an upset conditien transient, total-10 occurrences), water at 100*F is injected L into the pressurizer for 300 seconds. At the end of the transient, average pressurizer water temperature drops to 543*F (AT of 110*F).

After the spray is over, the pressurizer fluid temperature uniformly increates to the normal operating condition in approximately 1.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />.

This transient data shows that a maximum cooldown of 200*F in any 1-hour period is maintained.

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w Trojan Nuclear Plant Mr. Steven A. Varga

~ Docket 50-344 December 29, 1986 License NPF-1 Attachment Page 2 of 3 Ouestion 3 What is the final metal. temperature?

Resoonse JAt the end of the postulated transient, inadvertent auxiliary spray (during which 100*F. water is injected into the pressurizer and the maximum differential in fluid temperature in the spray nozzle is Delta T = -560*F), the affected components have-the following temperatures.

Spray Nozzle Safety End: 100*F ,

Spray Nozzle.and Neighboring 200*F at inside surface to 500*F at Upper Heat portion: outside surface Shell Region where spray 105*F at inside surface to 461*F at contacts the wall: outside Question 4 What is the RTNDT of the material?

Resoonse The Trojan Nuclear Plant pressurizer was constructed in accordance with the'1968 Edition / Winter 1968 Addenda of the ASME B & PV Code Section III.

This edition / addenda did not require determination of RTNDT. Instead,-

, either drop weight tests or Charpy V-notch tests at 60*F below the lower of the vessel hydrotest temperature or the lowest service metal tempera-ture were required to be performed. Consistent with the Design Specifi-cation (676440, Rev. 4) these tests were performed at a temperature of less than or equal to 40*F. Review of the material test certificates for the spray nozzle forging, the upper head, and the shell barrels indicates that the Code requirements were satisfied at a test temperature of 10*F.

Question 5 Does the pressurizer maintain its integrity in accordance with Appendix G to 10 CFR 50?

Response

Yes, based upon the fracture toughness tests performed.

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. Trojan Nuclear Plant Mr. Steven A. Varga Docket 50-344 December 29, 1986' License NPF-1 Attachment Page 3 of 3 10 CFR 50, Appendix G, III.A includes the following:

To demonstrate compliance with the fracture toughness requirements, ferritic materials must be tested in accordance with the ASME Code. For a vessel that was constructed to an ASME Code earlier than the Summer 1972 Addenda of the 1971 Edition, the fracture toughness data and data analysis must be supplemented in a manner approved by the Director, NRC, to demonstrate equivalence with the fracture toughness requirements of this appendix.

10 CFR 50, Appendix G, III.C includes the following:

All fracture toughness test programs conducted in accordance with Paragraph A of this section must comply with ASME Code requirements . . .

As shown in response to Question 4 above, the fracture toughness-tests on

. the pressurizer pressure boundary materials .were conducted in accordance with the applicable edition / addenda of the ASNE Code,Section III.

Question 6 Is the spray nozzle austenitic or ferritic stainless steel?

Response

The spray nozzle forging material is SA-508 Class 2. This is a ferritic low alloy steel (not stainless). It is clad with austenitic stainless steel. The spray nozzle forging safe end material is SA-182 Grade F316L austenitic stainless steel. These are the materials which comprise the pressure boundary components of the spray nozzle. Note there is also an internal non-pressure boundary spray nozzle. This material is ASTM A-296, Crade CF-8M austeni ic stainless steel.

Question 7 Does 100*F water actually come in contact with the pressurizer wall, or is it heated and mixed?

Response

For the stress analysis purpose, it was conservatively assumed that all water from the nozzle strikes the vessel wall rather than allowing for any evaporation and/or mixing with the hotter steam. It is expected that for a transient of this nature, the cooler water will actually mix and not directly contact the pressurizer wall.

DLN/kal 1356W.1286