ML20199L833

Responds to NRC 971230 RAI Re 971006 Proposed License Amend, Implementing Mod to Install New Suction Strainers on Certain ECCS Pump Suction Lines.Revised Calculations M-51-62 & M-52-31,encl.AB Suppl Affidavit Also Encl

ML20199L833
Person / Time
Site:	Limerick
Issue date:	02/02/1998
From:	Cotton J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20199L838	List: ML20199L833 ML20199L841 ML20199L848
References
GL-97-04, GL-97-4, IEB-96-003, IEB-96-3, NUDOCS 9802100042
Download: ML20199L833 (10)

Text

, , John s. cotton

,- Vos hrsdont Station Support i NRCB 96-03 PECO NUCLEAR pcmen A Unit of PECO Energy gyjgQ19087mgg February 2,1998 Docket Nos. 50 352 50 353 License Nos. NPF 39 NPF 85 U.S. Nuclear Regulatory Commission Attn: Document Control Desk i Washington, DC 20555-0001

Subject:

Limerick Generating Station, Units 1 and 2 Response to Request for Additional Information Emergency Core Cooling System Suction Strainer Modification

Dear NRC Officials:

(

By letter dated October 6,1997, PECO Energy submitted license amendment requests for Limerick Generating Station (LGS), Units 1 and 2, to facilitate implementation of a plant modification to install new suction stralners on certain Emergency Core Cooling System (ECCS) pump suction lines. PECO Energy requested the license amendments since the 10CFR50.59 evaluation that was performed in support of the plant modification concluded that a portion of the proposed modification involved an unreviewed safety question (USQ). The regulations require that, for any changes to the facility involving a USO, the licensee shall submit an application for amendment to its license pursuant to 10CFR50.90. The USQ that was identified pertains to the design assumptions used in determining the amount of debris that would be expected to be generated under Loss of Coolant Accident (LOCA) conditions and the amount of material that would be transported to the suppression pool. We are requesting that, when approved, the Issuance of the amendments coincide with the schedule for completing the modification on each LGS unit. l/

Subsequently, by letter dated December 30,1997, the NRC requested additional information concerning the proposed plant modification at LGS, Units i and 2. The letter identified two (2) issues in which supplemental information is needed in order for the NRC to continue its review of h CM) the license amendment requests. The questions identified by the NRC aro restated below followed by our response. This information is being submitted under affirmation, and the -

associated affidavit is enclosed.

P DO O PDR.

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February 2,1998 Page 2 Question i Attachment 1 of the October 6, f 997, submittalstates that 'the margin of safety for toe ECCS system is defined by the flow rates produced by the pumps. If the required NPSH is maintained, the ECCS pumps will deliver the rated flow. The replacement suction stralners are designed to maintain the pressure drop across a fully fouled stralner to 2 feet less 'han the available NPSH margin for the RHR and Core Spray pumps under design basis LOCA conditions with the maximum combined Insulation and corrosion product loading.' This statement implies that the new stralners willreduce the available NPSH margin by 2 feet. Provide a copy of the NPSH analyses for the RHR and Core Spray pumps with the new ECCS stralner design.

Resoonse Attached is information conceming the Net Positive Suction Head (NPSH) analyses performod for the Residual Heat Removal (RHR) system and Core Spray (CS) system pumpt for LGS, Unit 1. The analyses provided assume installation of the new strainers.

Attachmont i provides the NPSH analyses associated with the RHR system, and Attachment 2 contains the information for the CS system. The NPSH analyses for the Unit 2 RHR and CS systems pumps are not included, since these analyses have not yet been updated to reflect the new strainer design values.

In addition, PECO Energy believes that further clarification is necessary in explaining how the 2 feet of margin was discussed in our October 6,1997, submittal. Although no margin is required for NPSH, the proposed design basis for sizing the new strainers limits the head loss of a fully fouled strainer, thus retalning a minimum NPSH margin of 2 feet for each ECCS pump. The margin of 2 feet was retained to provide operational flexibility and allow for minor inaccuracles in the calculational methodology. This results in an allowable head loss for a RHR suction strainer of 12 feet (i.e.,14 feet 2 feet) and an allowable head loss for a CS suction strainer of g.2 feet (i.e.,11.2 feet 2 feet) at a temperature of 212'F.

Question 2 The staffis aware that the Limerick ECCS is designed to meet the guidance specified in Safety Guide 1,

• Net Positive Suction Hcad for Emergency Core Cooling and Containment Heat Removal Systsm Pumps,' Revision 0, and that Limerick Generating Station intends to continue to meet the guidance of Safety Guide 1. The staff also needs to knowif there are or will bo any other modifications to the NPSH analyses, besides the strainer debris loading head loss, that are different from the last previously approved NPSH analyses. Provide a description of alldifferences between the NPSH analyses with the new ECCS strainers and the previously reviewed and approved NPSH analyses.

1 February 2,1998  ;

Page 3 1

Response

By letter dated December 30,1997, PECO Energy submitted a response to Generic Letter (GL) 97 04," Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps," for LGS, Units 1 and 2, and Peach Bottom Atomic Power Station, Units 2 and 3. In our response to this GL, PECO Energy provided information for LOS describing any differences between the current

, design basis NPSH analysis and the most recent analysis reviewed and accepted by the NRC.

As indicated in the GL 97 04 response, a summary of the NPSH analysis for the LGS  !

RHR system was submitted as part of the licensing application for the LGS Power Rorate Project. The NRC issued a Safety Evaluation Report (SER) for this submittal, in addit'on, the NRC losued an SER for the original analysis contained in the LGS Updated Flaal Safety Analysis Report (UFSAR) Section 6.3.2.2.4. With respect to the CS system, the NPSH analysis was never formally reviewed by the NRC.

4 The current design-basis NPSH analysis for the LGS RHR system does di'for from the -

most recent analysis reviewed and accepted by the NRC for which an SER was issued.

Additional conservatism is included in the current design basis analysis that was not included in the LGS UFSAR or Power Rorate Project submittal discussion. This additional conservatism accounts for pipe aging, conservative flowrate and additional pressure drop across the existing suction strainers. For LGS, Unit 1, the most recent NPSH analysis considers the pressure drop across the new large-capacity strainers for the RHR and CS systems. The Unit 2 analyses have not yet been updated to include the new strainer design values.

Also enclosed is an affidavit prepared by ABB supporting the submittal of proprietary information

related to the strainer modification activities. This affidavit supplements the ABB affidavit previously submitted in our October 6,1997, letter. This affidavit was prepared in order to correct a typographical error that was identified in referencing the title of a calculation in the original af"idavit.

If you have any questions or require additional information, please do not hesitate to contact us.

Very truly yours, Wnf &

Attachments Enclosures cc: H. J. Miller, Administrator, USNRC, Region I (w/ attachments, enclosures)

A. L. Burritt, USNRC Senior Resident inspector, LGS (w/ attachments, enclosures) ,

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ENCLOSURE 1 l

l PECO Energy l Affidavit

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i COMMONWEALTH OF PENNSYLVANIA  :

ss.

COUNTY OF PHILADELPHIA  :

J. B. Cotton, being first duty swom, deposes and says:

That he is Vice President of PECO Energy Company, the Applicant herein; that he has read the -

l foregoing response to the request for additional information for Limerick Generating Station, Unit 1 and 2 Facility Operating License Nos. NPF 39 and NPF-85, regarding the resolution of the unreviewed safety question associated with the debris generation and transport methodology used th wpport of the Emergency i

l Core Cooling System suction strainer modification, and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information, and belief.

, 4, N 4)

Vice President Subscribed and swom to before me thishk day b 1998.

QJtatn Notary Public NOTARIAL SEAL CAMOL A. WALTON. Notary Pusan City of PhuadelpNo. hule.

h6an f.apues MarJ$.

4 1

ENCLOSURE 2 ABB Supplemental Affidavit w ~

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4 AEEIDAVIT PUREUANI TO 10 CFR 2.790 I, S.E. Ritterbusch, depose and say that I am the Manager, Licensing Projects, of Combustion Engineering, Inc., duly autholized to make this affidavit, and have reviewed or caused to have reviewed the information which is identified as proprietary and referenced in the paragraph immediately below. I am submittin0 this affidavit in conjunction with the application of PECO Energy and in conformance with the provisions of 10 CFR 2.700 of the Commission's regulations.

The information for which proprietary treatment is sought is contained in the following document:

MISC PENG CALC 059, REV. 00, *Models for Sizing and Evaluating Performance of BWR Replacement Strainers with Pleated Surfaces", July 1997 This document has been appropriately designated as proprietary.

I have personal knowledge of the criteria and procedures utilized by Combustion Engineering in designating information as a trade secret, privileged or as confidential commercial or financial information.

Pursuant to the provisions of paragraph (b) (4) of Section 2.790 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, included in the above referenced document, should be withheld.

1. The information sought to be withheld from public disclosure, is owned and has been held in confidence by Combusbon Engineering. It consists of information concerning the test data and methods for calculating Emergency Core Cooling System (ECCS) strainer size.

2-

2. The information consists of test data or other similar data concerning a process, method or component, the application of which results in I substantial competitive advantage to Combustion Engineering.

3. The information is of a type customarily held in confidence by Combustion Enginenring and not customarily disclosed to the public. Combustion Engineering has a rational basis for determining the types of information '

customarily held in confidence by it and, in that connection, utilizes a system to determine when and whether to hold cerialn types of information in confidence. The details of the aforementioned system were provided to the Nuclear Regulatory Commission via letter DP 537 from F. M. Stern to Frank Schroeder dated December 2,1974. This system was applied in determining that the subject document herein is proprietary.

4. The information is being transmitted to the Commission in confidence under the provisions of 10 CFR 2.790 with the understanding that it is to be received in confidence by the Commission.

5. The information, to the best of my knowledge and belief, is not available in public sources, and any disclosure to third parties has been made pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in confidence.

6. Public disclosure of the information is likely to cause substantial harm to the competitive position of Combustion Engineering because:

a. A similar product is manufactured and s,ld by major pressurized water reactor competitors of Combustion Engineering.

b. Development of this information by Combustion Engineering required hundreds of thousands of dollars and tens of thousands of manhours of effort. A competitor would have to undergo similar expense in generating equivalent information.

. . . . c 3-

c. In order to acquire such information, a competitor would also require considerable time and inconvenience to develop (est l

data and methods for calculating ECCS strainer size.

.d. The information consists of test data and methods for calculating ECCS strainer size, the application of which

provides a competitive economic advantage. The availability of such information to competitors would enable them to modify their product to better compete with Combustion Engineering, take marketing or other actions to improve their product's position or impair the position of Combustion Engineering's product, and avoid developing similar data and analyses in support of their processes, methods or apparatus.

e, in pricing Combustion Engineering's products and services, significant research development, engineering, analytical, manufacturing, licensing, quality assurance and other costs and expenses must be included. The ability of Combustion Engineering's competitors to utilize such information without similar expenditure of resources may enable them to sell at prices reflecting significantly lower costs.

l

f. Use of the information by competitors in the international marketplace would increase their ability to market nuclear steam supply systems by reducing the costs associated with their technology development. In addition, disclosure would have an adverse economic impact on Combustion Engineering's notential for obtaining or maintaining foreign licensees.

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. e4 Further the deponent sayeth not, i S.E. Ritterbusch, Manager Licensing Porjects Sworn to before me  !

-this /[# day of L UAntw9 ,1998 l

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Nota [PublicO My commission expires:- 8/

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