LIC-04-0055, Omaha Public Power District'S Response to Request for Additional Information, Relief Request for Previous Repair of Pressurizer Nozzle
| ML041240423 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 04/29/2004 |
| From: | Phelps R Omaha Public Power District |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CAW-04-1772, LIC-04-0055 | |
| Download: ML041240423 (16) | |
Text
m-Omaha Public Pover Distict 444 South 16th Street Afall Omaha NE 68102-2247 April 29, 2004 LIC-04-0055 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
References:
- 1. Docket No. 50-285
- 2. Letter from OPPD (D. J. Bannister) to NRC (Document Control Desk) dated July 25, 2003, Relief Request for Previous Repair of Pressurizer Nozzle (LIC-03-0099)
- 3. Letter from NRC (A. B. Wang) to OPPD (R. T. Ridenhoure) dated March 30, 2004, FCS Unit No. 1 Request for Additional Information on Relief Request for Previous Repair of Pressurizer Nozzle (TAC No. MC0196)
- 4. NRR Office Instruction LIC-204, Revision 2, Handling Requests to Withhold Proprietary Information from Public Disclosure Effective, dated April 2, 2004
SUBJECT:
Response to Request for Additional Information, Relief Request for Previous Repair of Pressurizer Nozzle In support of the relief request, "Relief Request for Previous Repair of Pressurizer Nozzle" (Reference 2), the Omaha Public Power District (OPPD) provides the attached information in response to the Nuclear Regulatory Commission's (NRC's) Request for Additional Information of Reference 3.
Pursuant to 10 CFR 2.790, OPPD requests that the information in Enclosures 2, 3, and 4 be withheld from public disclosure. Westinghouse Electric Company considers this information to be proprietary as justified in the supporting affidavit (Attachment B). In accordance with Section 4.2 of Reference 4, nonproprietary versions of the analyses of Enclosures 3 and 4 are not provided because a nonproprietary version would be of no value to the public due to the extent of the proprietary information.
I declare under penalty of perjury that the forgoing is true and correct. (Executed on April 27, 2004). No commitments are made in this letter.
Employment with Equal Opportunity
U. S. Nuclear Regulatory Commission LIC-04-0055 Page 2 If you have any questions or require additional information, please contact Dr. R. L. Jaworski of the FCS Licensing staff at (402) 533-6833.
Sincerely, R. L. Phelps Division Manager Nuclear Engineering RLP/RLJ/rlj Attachments:
A. Response to NRC Request for Additional Information-Relief Request for Previous Repair of Pressurizer Nozzle B. Affidavit from Westinghouse Electric Company Supporting Proprietary Nature of Referenced Documents
Enclosures:
- 1. Reference 7.1, Westinghouse Letter CSE-2000-106 dated October 25, 2000 (with attachment) -Non-proprietary
- 2. Reference 7.1, Westinghouse Letter CSE-2000-106 dated October 25, 2000 (with attachment) - Proprietary
- 3. Reference 7.2, Westinghouse Electric Company LLC Calculation Note Number CN-CI-02-74, Revision 1, "Evaluation of Fatigue Crack Growth of Postulated Flaw At Omaha Fort Calhoun Pressurizer Lower Shell Instrumentation Nozzle," dated April 16, 2004 -
Proprietary
- 4. Reference 7.3, Westinghouse Electric Company LLC Calculation Number A-OPPD-9449-1253 Rev. 0, "Evaluation of a Shell Side Temperature Nozzle Repair for Omaha Public Power Pressurizer," dated November 3, 2000 - Proprietary c: B. S. Mallett, NRC Regional Administrator, Region IV A. B. Wang, NRC Project Manager J. G. Kramer, NRC Senior Resident Inspector
LIC-04-0055 Attachment A Page I Response to NRC Request for Additional Information Relief Request for Previous Repair of Pressurizer Nozzle NRC Question 1:
Please provide Reference 7.1, Westinghouse Letter CSE-2000-106 dated October 25, 2000 (with attachment), and Reference 7.2, Westinghouse Electric Company LLC Calculation Note Number CN-CI-02-74, Revision 0, "Evaluation of Fatigue Crack Growth of Postulated Flaw At Omaha Fort Calhoun Pressurizer Lower Shell Instrumentation Nozzle," dated January 8, 2003, for our review.
OPPD Response: provides Reference 7.1, Westinghouse Letter CSE-2000-106 dated October 25, 2000 (with attachment). Enclosure 2 provides Reference 7.2, Westinghouse Electric Company LLC Calculation Note Number CN-CI-02-74, Revision 1, "Evaluation of Fatigue Crack Growth of Postulated Flaw At Omaha Fort Calhoun Pressurizer Lower Shell Instrumentation Nozzle," dated April 16, 2004. Revision 1, completed in 2004, updated the Revision 0, produced for Fort Calhoun in 2003, to include heatup and cooldown insurge transients, revise stress linearization methodology, raise the cooldown end temperature to 1200 F, and correct crack growth programming errors.
NRC Question 2:
Confirm that there is no built-in interference between the pressurizer vessel and the pressurizer nozzle.
OPPD Response:
There is no built-in interference between the pressurizer vessel and the pressurizer nozzle. The relationship between the bore of the pressurizer vessel and the nozzle OD allows a range of tolerances which are accounted for in the calculation presented in Enclosure 4. These values are consistent with the ASME Code requirements for partial penetration welds specified in NB-3337.3.
NRC Question 3:
Provide the stress analysis results of the repaired vessel-nozzle configuration considering the operating stresses and the residual stresses caused by the Inconel 152 overlay and the partial penetration weld. The stress analysis results should include gap or interference of the entire cylindrical surface between the vessel and the nozzle and the stresses of the weld overlay, the partial penetration weld, and the adjacent nozzle section. Meeting the American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section III stress criteria needs to be demonstrated because this repair changes the pressure boundary and therefore is, by nature, of new construction.
LIC-04-0055 Attachment A Page 2 OPPD Response: provides Reference 7.3, Westinghouse Electric Company LLC Calculation Number A-OPPD-9449-1253 Rev. 0, "Evaluation of a Shell Side Temperature Nozzle Repair for Omaha Public Power Pressurizer," This calculation, performed in accordance with Section III of the ASME Code in November, 2000, includes the analysis and results of the repaired vessel-nozzle configuration.
NRC Question 4:
If the stress analysis results indicate that a local gap exists in front of the weld, provide a fatigue crack growth analysis on the crack in front of the partial penetration weld. If the stress analysis results indicate that a continuous passage exists from the top of the original J-groove weld to the new partial penetration weld, provide a primary water stress corrosion cracking and fatigue crack growth analysis on the crack in front of the partial penetration weld.
OPPD Response: provides Reference 7.3, Westinghouse Electric Company LLC Calculation Number A-OPPD-9449-1253 Rev. 0, "Evaluation of a Shell Side Temperature Nozzle Repair for Omaha Public Power Pressurizer." This stress analysis shows acceptable fatigue characteristics of the weld using a stress concentration factor of 5 at the root of the weld. As a result, fatigue cracking in this location is not anticipated and no additional analysis is required.
LIC-04-0055 Attachment B Page 1 Affidavit from Westinghouse Electric Company Supporting Proprietary Nature of Referenced Documents
LIC-04-0055 Attachment B Page 2
( )Westinghouse -Westinghouse Ekcric Company NuclearSenrices
- P.O Box 500 WindsorConnecticut 06095-0500 USA U.S. Nuclear Regulatory Commission Direct tel: 860-731-6289 Document Control Desk Directfax 860-731-6238 Washington, DC 20555-0001 e-mail: ian.crickard@us.westinghousecon Ourref CAWV-0-1772 April 20. 2004 APPIACATION FOR WITIIIOlDITNG PROPRIETARY INFORMATION FROM11 PUBLIC DISCLOSURE
Reference:
(1) Letter CSE-2000-106, D. Siska to K. Hyde, 'Technical Justification for Weld Rcpair of Fort Calhoun Side Shell and Upper Pressurizer Nozzles," dated 10/25/2000.
(2) Westinghouse Calculation CN-CT-02-74 R01, 'Evaluation of Fatigue Crack Growth of Postulated Flaw at Omaha Fort Calhoun Pressurizer Lower Shell Instrumentation Nozzlc," 4116104.
(3) Westinghouse Calculation A-OPPD-9449-1253 ROO, "Evaluation of a Side Shell Temperature Nozzle Repair for Omaha Public Power Pressurizer," 11/3/2000.
Westinghouse hereby transmits the above-referenced proprietary documents for which withholding is requested pursuant to Affidavit CAW-04-1772. This affidavit, which accompanies this letter and is signed by the owner of the proprietary information, Westinghouse Electric Company LLC, sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in 10 CFR Section 2.390(b)(4) of the Commission's regulations.
This letter also authorizes use of the accompanying affidavit by Omaha Public Power District.
In conformance with the requirements of 10 CFR 2.390, Westinghouse confirms that the information contained within the referenced documents is proprietary. Thejustification for claiming these documents as proprietary is identified in Sections (4)(iiXa) through (4Xii)(f) of the enclosed affidavit. Westinghouse also affirms that a nonproprietary version of these calculations does not exist and, due to the extent of proprietary information contained, a nonproprietary version of such calculations would be meaningless.
Communication with respect to the proprietary aspects of the application for withholding or the Westinghouse affidavit should reference this letter, CAW.04-1772, and be addressed to the undersigned.
Very truly yours, Licensing Project Manager Rogulatory Compliance and Plant Licensing
Enclosure:
cc: G. S. Shukla (NRC)
A BNFL Group Company
LIC-04-0055 Attachment B Page 3 CAW-041772 bcc: J. A. Grcsham (ECE 4-7A)
C. B. Brink-man, (Rockhille. MD 20S52)
R. Bastien, (Nivelles, Belgium)
C. A. Nielsen (WestinghousIOPPD)
D. P. Siska (Chattanoosa)
RCPL Administrative Aide (ECE 4-7A)
LIC-04-0055 Attachment B Page 4 CAW-04.
AFFIDAVIT STATE OF CONNECTICULT )
) ss: WINDSOR, CT COUNTY OF HARTFORD )
Before me, the undersigned authority, personally appeared Ian C. Rickard, who, being by me duly swc according to law. deposes and says that he is authorized to execute this Affidavit on behalf of Westinghouse Electric Company LLC ("Westinghouse"), and that the avenrents of fact set forth in thi Affidavit arc true and correct to the best of his knowledge, information, and belief:
Ian C. Rickard, Licensing Project Manager Regulatory Compliance and Plant Licensing Sworn to and subscribed before me this 20e day of April 2004.
Pub-ic My commission expires May 31, 2008.
LIC-04-0055 Attachment B Page 5 CAWV-04-1772 (1) 1, tin C. Richard, depose and say that I am the Licensing Project Manager in Nuclear Services, Westinghouse Electric Company LLC ("Westinghouse"), and as such I have been specifically delegated the function of reviewing the proprietary infonnation sought to be withheld from public disclosure in connection witlinuclear power plant licensing and rule making proceedings, and am authorized to apply for its withholding on behalf of the Westinghouse Electric Company LLC.
(2) 1am making this Affidavit in conformance with the provisions of 10 CFR Section 2.390 of the Comrnmission's regulations and in conjunction with the WVestinghouse application for withholding accompanying this Affidavit.
(3) 1have personal knowledge of the criteria and procedures utilized by the Westinghouse Electric Company LLC in designating information as a trade secret, privileged or as confidential commercial or financial informration.
(4) Pursuant to the provisions of paragraph (b)(4) of 10 CFR Section 2390 of the Commission's regulations, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.
(i) The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse.
(ii) The information is of a type customarily held in confidence by Westinghouse and not customarily disclosed to the public. Westinghouse has a rational basis for determining the types of infornmation customarily held in confidence by it and, in that connection, utilizes n system to determine when and whether to hold certain types of information in confidence.
The application of that system and the substance of that system constitute Westinghouse policy and provide the rational basis required.
Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:
(a) The information reveals the distinguishing aspects of a process (or component, strmcture, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.
(b) It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage, e.g., by optimization or improved marketability.
(c) Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, rmainufacture, shipment, installation, assurance of quality, or licensing a similar product.
LIC-04-0055 Attachment B Page 6 CAW-04-1772 (d) It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.
(e) It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.
(f) It contains patentable ideas, for which patent protection may be desirable.
(iii) There are sound policy reasons behind the Westinghouse s)stem for classification of proprietary informnation, which include the following:
(a) The use of such infornation by Westinghouse gives Westinghouse a competitive advantage over its competitors. It is, therefore, withheld from disclosure to protect the Westinglhouse competitive position.
(b) It is infornation that is marketable in manye ways. The extent to which such information is available to competitors diminishes the Westinghouse ability to sell products and services involving the use of the infornmatiol.
(c) Use by our competitor would put Westinghouse at a competitive disadvantage by reducing his expenditure of resources at our expense.
(d) Each component of proprietary information pertinent to a particular competitive advantage is potentially as valuable as the total competitive advantage. If competitors acquire components of proprietary information, any one component may be the key to the entire puzzle, thereby depriving: Westinghouse of a competitive advantage.
(e) Unrestricted disclosure would jeopardize the position ofprominence of Westinghouse in the world market, and thereby give a market advantage to tlhe competition of those countries.
(f) The Westinghouse capacity to invest corporate assets in research and development depends upon the success in obtaining and mraintaining a competitive advantage.
(iv) The infonrnation is being transmitted to the Commission in confidence and, under the provisions or 10 CFR Section 2390, it is to be received in confidence by the Commission.
(v) Thle infornation sought to be protected is not available in public sources or available information has not been previously employed in the same original manner or method to the best ofour knowledge and belief.
(vi) The proprietary information sought to be withheld in this submittal is that which is contained in (1) Letter CSE-2000-106, D. Siska to K. Hyde, 'Technical Justification for WVeld Repair of Fort Calhoun Side Shell and Upper Pressurizer Nozzles:' dated I0'25/2000; (2) Westinghouse Calculation CN-CI-02-74 ROI, "Evaluation of Fatigue Crack-Growth of Postulated Flaw at Onalha Fort Calhoun Pressurizer Lovver Shell
LIC-04-0055 Attachment B Page 7 CAW-04-1772 Instrumentation Nozzle ' 4116/04; and (3) Westinghouse Calculation A-OPPD-9449-1253 ROO, "Evaluation of a Side Shell Temperature Nozzle Repair for Omalh Public Power Pressurizer," 11/3/2000.
The information is part of a model that will enable WVestinghouse to evaluate the fatigue crack growth of a postulated flaw in the Fort Calhoun Station pressurizer, and in particular to supporting utilities with CE NSSS plants in the application of such, including (a) The identification of important phenomena relevant to the application of the fatigue crack growvth model, including quantification of dominant failure mechanisms, operational considerations and model implementation, (b) A generic methodology for the applicability of the fatigue crack growth model to utilities with CE NSSS plants, and (c) An evaluation of problems with pressurizer nozzles in CE NSSS plants that have common cause implications and the probability of such events leading to nozzle failure.
Further this information has substantial commercial value as follows:
(a) Westinghouse plans to sell the use of similar information to its customers for purposes of meeting NRC requirements for licensing documentation.
(b) Westinghouse can sell the application and defense of the fatigue crack growth evaluation model.
(c) The information requested to be withheld reveals the distinguishing aspects of a methodology that was developed by Westinghouse.
Public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar advanced nuclear power plant designs and to provide licensing defense services for commercial power reactors wvithout commensurate expenses. Also, public disclosure of the infornation would enable others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.
The development of the technology described in part by the infonnation is the result of applying the results of many)years ofexperience in an intensive Westinghouse effort and the expenditure of a considerable sum of money.
In order for competitors of Westinghouse to duplicate this information, similar technical programs would have to be performed and n'significant manpower effort, having the requisite talent and experience, would have to be expended.
Further the deponent sayeth not.
LIC-04-0055 Attachment B Page 8 CAw-04--1772 PROPRIETARY INFORMATION NOTICE In order to conforn to the requirements of 10 CFR 2.390 of the Commission's regulations concerning the protection of proprietary information so submitted to the NRC, Westinghouse confirms that the infonnation in (1) Letter CSE-2000-106, D. Siskla to K. Hyde, "Technical Justification for Weld Repair of Fort Calhoun Side Shell and Upper Pressurimr Nozzles," dated 10/25/2000; (2)
Westinghouse Calculation CN-CI-02-74 R01, "Evaluation of Fatigue Crack Growth of Postulated Flaw at Omnaha Fort Calhoun Pressurizer Lower Shell Instrumentation Nozzle," 4/11604; and (3)
Westinghouse Calculation A-OPPD-9449-1253 ROO, "EaIluation of a Side Shell Temperature Nozzle Repair for Omaha Public Power Pressurizer," 1 1/312000 is proprietary. The justification for claiming this infornntion as proprietary is indicated in Sections (4XiiXa) through (4)(ii)(f) of affidavit CAW-04-1772 accompanying this transmittal.
COPYRIGUT NOTICE The information transmitted herewith is copyright by WVestinghouse. The NRC is pernitted to make the number of copies of the information that are necessary for its internal use in connection with generic and plant-specific revievws and approvals as *x11 as the issuance, denial, amendment, transfer, renewal, modification, suspension, revocation, or violation of a license, pennit, order, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on public disclosure to the extent such information has been identified as proprietary by Westinghouse, copyright protection notwithstanding. Copies made by the NRC must include the copyright notice in all instances and the proprietary notice if the original was identified as proprietary.
LIC-04-0055 Page 1 Reference 7.1, Westinghouse Letter CSE-2000-106 dated October 25, 2000 (with attachment)
Non-Proprietary
Westinghouse Non-Proprietary Class 3 Westinghouse Electric Company 1201 Riverfront Parkway Nuclear Services Chattanooga, TN 37402 October 25, 2000 CSE-2000-106 Mr. Kevin Hyde Omaha Public Power District Fort Calhoun Station P.O. Box 399 Fort Calhoun, NE 68023
SUBJECT:
TECHNICAL JUSTIFICATION FOR WELD REPAIR OF FORT CALHOUN SIDE SHELL AND UPPER PRESSURIZER NOZZLES
Reference:
Westinghouse (Chattanooga) ASME Code Design Report CENC-1 130, Analytical Report for Omaha Pressurizer, April 1970.
Dear Mr. Hyde:
Westinghouse has performed an analysis of the'unsevered upper head and side shell temperature nozzles using a classical two-body interaction procedure. Conservative assumptions were made to allow use of the referenced stress report models with the addition of thermal stresses Induced by the added restrairlt'assumlng the nozzles were also welded at the O.D. of the weld pad. Results of the' analysis showed the side shell temperature nozzle Is acceptable without severing the nozzle for the lifetime of the plant. However, the conservative analysis showed the added thermal stresses would not be acceptable for fatigue usage factor of the upper head nozzles.
The usage factor for the upper head nozzles was calculated for stress concentration factors (SCF) of 5 and 4. The allowable number of heatup and cooldown cycles for the SCF of 5 was predicted to be approximately 100; the allowable number for a SCF of 4 essentially doubled the allowable cycles to 200. Thus, as long as Fort Calhoun can verify they will have less than 100 heatup and cooldown cycles before the next outage, the analysissbows it Is acceptable for to leave the upper head nozzle unsevered. Westinghouse Is confident thatfa more detailed analysis will show that the nozzle ran remain unsevered for the lifdtir'rie of the plant..'
Westinghouse has also evaluated the effect of boric acid on corrosion of the base metal under a crack and determined it will be negligible. This conclusion is based on the attached letter which concludes that a (( )) gap in corrosion resistant material on the Palo Verde hot legs will not adversely affect the estimated nozzle repair lifetime f[ )). Since the (( )) gap Is considerably larger than the crack in the pressurizer side shell nozzle, the attached letter bounds the potential corrosion effects on the Fort Calhoun pressurizer.
Please contact me at 423-752-2833 If there are any questions or if you would like to discuss the details of this evaluation.
Sincerely, D.P. Siska, Supeivlsor Field Services Engineering
Westinghouse'Non-Proprietary Class 3 Westinghouse Elec tic Company 2000 Day Hu Road Nuclear Services W.ndsor. CT 06095 October 10, 2000 Mr. Rex Meeden Arizona Public Service Palo Verde Nuclear Generating Station 5801 South Wintersburg Road Tonopah, AZ 8S354
Subject:
IUffect of Increased Gap in (lie HnIf-Nozzle Repair on Carbon Steel Pipe Corrosion Evaluation
Reference:
Report No. 98-TR-1;SW-030 Rev 00, "Ilalf-Nuzzlc Repair- Carbon Steel Corrosion Bvaluation
Dear Mr. Meeden:
Arizona Public Service plans to replace several hot leg, Alloy 600 nozzles at Palo Verde-2 during the current outage. The repair process will use the half-nozzle approach In which the existing nozzle is cut outboard of the weld between the nozzle and pipe, inserting a short length of Alloy 690 nozzle and making a new weld on the pipe OD. This technique leaves a small gap between the old and new nozzles through which borated water can enter the crevice between the nozzles and carbon steel piping. A section of the Alloy 600 nozzle and the original 1-weld remain in place. When this process was first implemented, there were concerns about the corrosion of the carbon steel in the nozzle bore hole and the propagation orcrmcks through the Alloy 600 nozzles and weld metals to the pipe material where the crack could continue to grow by a stress corrosion cracking or fatigue mechanism.
The referenced report evaluated these concerns for the Palo Verde Units and concluded the following:
The corrosion rate for carbon steel exposed to borated water under the conditions expected at Palo Verde as a result of a half-nozzle repair will be low ((
)) and the nozzle repairs will have a lifetime of (( .1]
Cracks that may be present in tie Alloy 600 nozzle or weld metal will not continue to propagate through the carbon steel pipe because of the low oxygen levels which will result in corrosion potentials below the critical cracking potential for carbon steel, and
- A minor amount of fatigue crack growth may occur if stress conosion cracks in the nozzles propagate to the carbon steel.
Westinghouse Non-Proprietary Class 3 These findings, which wcre based on laboratory test data and field experience, result In the overall conclusion that the hall-nozzle repair is a viable long enmn repair option for small diameter Alloy 600 nozzles such as those in the hot leg piping of the Palo Verde plants.
During our conversation of October 4, 2000, you indicated that the gap between the remnants of
- the original Alloy 600 nozzles and the new Alloy 690 half-nozzles would be ((
.1] You inquired about the effects, if any, of this change on the conclusions of the referenced report.
The change that you indicated would be implemented will not have any affect on the conclusions of the referenced report. Increasing the gap may permit greater exchange of the borated water in the crevices with the bulk coolant. The corrosion data used to estimate repair lifetinme was developed fromi specimens exposed to bulk water conditions and not to crevice conditions. The hulk wvatcr conditions are more conservative that the crevice conditions because corrosion products will forn and evcnmlilly fill the crevices reducing access of the borated water to the carbon steel. This will reduce the corrosion rate. Further, the chemical characteristics of the water In the crevices will change as a resulr of tie corrosion products being present with the result that the solution will become even less aggressive to the carbon steel. Thus, the increased gap between the nozzles will not adversely affect the estimated nozzle repair lifetime -
Since tile gap is not near the weld, increasing the width of the gap will not result Inan increase in the susceptibility of the curbon steel to stress corrosion cracking nor will it affect the transients used to calculate fatigue crack growth.
Iryou need additional Infornation, please contact me.
John F. 1-all Prin Consultant W000063 cc: K. M.Rajan D. P. Siska