3F1297-05, Forwards Rev 0 to Calculation M97-0121,IAW Commitment to re-evaluate Conclusion Re LOCA Effects of Jet Impingement

Forwards Rev 0 to Calculation M97-0121,IAW Commitment to re-evaluate Conclusion Re LOCA Effects of Jet Impingement

ML20203F102
Person / Time
Site:	Crystal River
Issue date:	12/13/1997
From:	Rencheck M FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20203F106	List: 3F1297-05, Forwards Rev 0 to Calculation M97-0121,IAW Commitment to re-evaluate Conclusion Re LOCA Effects of Jet Impingement ML20203F128
References
3F1297-05, 3F1297-5, TAC-M96604, NUDOCS 9712170287
Download: ML20203F102 (5)

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U.S. Nuclear Regulatory Commission i Attn: -Document Control Desk /

Washington, DC 20555-0001 Protection Against Dynamic Effects of Less of Coolant Accident,

Subject:

-Evaluation of Jet Impingement Effects of Pressurizer Surge Line, '

f Inspector Followup Item (IFI) 95-15-02(TACNo,M96604) g

References:

1. FPC to NRC letter, 3F1197-29, dated November 7, IC97 . I ,

L 2. NRC to FPC letter, 3N1097-09, dated October 9, 1997 -<

3. FPC to NRC letter, 1F0997-01, dated September 29, 1997

4. FPC to NRC letter, 3F0697-13, dated June 5, 1997 g

( 1 5 '. NRC to FPC letter, 3N0497-12, dated April 10, 1997

Dear Sir:

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Florida Power Corporation (FPC) is hereby submitting this letter in accordance @U with a comitment in Reference 1 to re-evaluate the conclusions stated in < D Reference 3 regarding the loss-of-coolant accident (LOCA) effects of jet I impingement. Using a 30' jet cone angle for a Crystal River Unit 3 (CR-3) "1 Pressurizer Surge Lii.e circumferential rupture jet impingement, FPC evaluated the i effects on the Nuclear Services Closed Cycle Cooling (SW) System lines serving . -

the Reactor Coolant Pumps (RCP). References 2, 4, and 5 :re included for 1*

correspondence traceability on this issue.

One circumferential rupture location on the pressurizer swge line has the potential _ to impinge on a segment of SW System piping serving RCP-1A. Reference 7 3' excluded this segment of piping because it was not within the area of impact using a 20* jet impingement spray cone angle rather than the 30' angle as

, required by the CR-3 licensing basis. FPC re-evaluated the rupture location with

-a pot?ntial jet impingement spray cone angle of 30*.

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CRYSTAL RIVER ENERGY COMPLEX: 15780 W. Power Lkm Street

• Crystal Rwer, Rorida 34428-6700 e (352) 796 6486 A horldle hogress Canpany

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U. S. Nuclear Regulatory Commission j 3F1297-05 i Page 2 of 3 J 1

l In this re-evaluation, a segment of SW System piping serving RCP-1A is within the l area of the jet. Due to the impact of the jet spray, the piping stresses were greater than allowable stresses.

FPC performed an inelastic analysis. The worst case elastica 11y calculated stress for the affected W piping runs was converted to an equivalent effective stress by. dividing by the ratio of the plastic section modulus to the elastic section modulus. The ratios of effective stress to material yield stress, and pulse duration to system time period, were then used to derive the system ductility required to absorb the pulse energy using graphical information. In turn, the system ductility and the elastic modulus for the material were used to calculate equivalent strain.

The relationship between the elastic and inelastic properties of the SW piping material was used t; calc 4 ate the amount of strain energy absorbed during permanent deformation, in comparison to the total strain energy capacity of the piping at failure. The results show negligible permanent defornation, supporting the conclusion that considerable margin exists between the actual deformation and the deformation required to cause pressure bounuary failure of the SW piping.

Based on the analysis, the piping will experience a maximum strain of less than 0.01 in/in, which is well below the ultimate strain of 0.20 in/in for the pipe material (less than 5% of the ultimate strain). This analysis, FPC Calculation M 97-0121, Revision 0, is provlded for information as Attachment B to this letter.

The analysis shows that the SW System piping serving RCP-1A will not lose its structural integrity due to jet impingement from a postulated surge line rupture.

Therefore, FPC concludes there are no inoperable systems, structures, or components associated with this nonconformance with the CR-3 licensing basis.

The SW System and the Containment are operable. Also, there are no conflicts with the Improved Technical Specifications. FPC has prepared a Deficiency Report (DR 97-8092) in accordance with CR-3's corrective action program and a justification for continued operation _(JCO) consistent with the guidelines discussed in Generic letter 91-18, Revision 1, "Information to Licensees Regarding NRC Iaspection Manual Section on Resolution of Degraded and Nonconforming Conditions." The JC0 documents the conclusions presented in this letter. The JC0 concludes that a pressurizer surge line LOCA with a jet spray impinging on the SW piping coincident with a postulated single failure of a SW System containment isolation valve will not result in violation of containment integrity. Also, no post-accident SW System safety fFctions will be impaired.

FPC - also reviewed the guidance in NRC Inspection Manual 9900, Operability, Section 6.13. shich recommends the use of methodology in ASME III, Appendix F to establish operability for piping. The stress intensities associated with the strains calculated in FPC Calculation M 97-0121 are lower than the allowable stress intensities in Appendix F, Section F-1341.2. Therefore, FPC concludes the SW piping is operable under jet impingement loading associated with a pressurizer surge line LOCA.

U. 'S Nuclear. Regulatory Commission 3F1297-05 Page 3 of 3' Based on the JCO and this letter, FPC will close Restart Issue D-58, " Design Requirements for Dynamic LOCA Effects," to resolve IFI 95-15-02. This issue will not be a restart restraint for CR-3.

FPC is evaluating several approaches to resolve this nonconformance. The

approaches under consideration include hardware modifications, such as a jet

-impingement shleid, re-routing of SW piping, or installation of additional-isolation valves; or a license amendment request to change the.CR-3 licensing basis. FPC will advise the NRC of the planned approach for resolution of this issue by May 29, 1998.

FPC evaluated the extent of condition of possible dynamic interactions with the SW System piping as a result of a LOCA. The circumferential rupture discussed above is the only vulnerability identified. This was verified by plant walkdowns and analyses.

The commitments in this letter are contained in Attachment A. If you have any further questions, please contact Mr. David Kunsemiller, Manager, Nuclear Licensing at (352)563-4566.

Sincerely, M. W. Rencheck, Director Nuclear Engineering _and Projects MWR/jwt Attachments

-xc: Regional Administrator, Region II Senior Resident Inspector NRR Project Manager

U.- S.- Nuclear Regulatory Comission Attachment A" 3F1297-05 Page 1-of 1 List of Regulatory Commitments ,

The- following table identifies those actions comitted to by Florida Power Corporation in this document. Any other actions discussed in the submittal represent intended or planned actions by Florida Power Corporation. They are described to the NRC for the NRC's information and are not regulatory comitments. Please notify the Manager, Nuclear Licer. sing of any questions regarding this document or any associated regulatory comitments.

COMMITMENT IMPLEMENTATION FPC is evaluating several approaches to resolve this May 29, 1998 nonconformance. The approaches under consideration incibJe hardware modifications, such as a jet impingement shield, re-routing of SW piping, or installation of additional-isolation valves; or a license amendment request to change the CR-3 licensing basis. FPC will advise the NRC of the planned approach for resolution of this issue.

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U.::$.- Nuclear Regulatory Commission?

. . 3F1297-05:- - - -

+: - ATTACHMENT B :

FPC CALCULATION'M 97-0121, REVISION 0- --

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