U-602896, Provides 90-day Response to GL 97-04, Assurance of Sufficient Net Positive Suction Head for ECC & Containment Heat Removal Pumps

Provides 90-day Response to GL 97-04, Assurance of Sufficient Net Positive Suction Head for ECC & Containment Heat Removal Pumps

ML20198B288
Person / Time
Site:	Clinton
Issue date:	12/29/1997
From:	Jackie Cook ILLINOIS POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-97-04, GL-97-4, U-602896, NUDOCS 9801060258
Download: ML20198B288 (5)

Text

. . I

• likno4s Power Company Chnton Power Station P o Box G78 Clinton. IL 61727 Tel 217 935 4623 l Fax 217 9354 632

' John G, Co'ok R Senior Wcs 'rctident l

e m. cm , . ,

U402896 l 80.120 l l

December 29, 1997  !

Docket No. 50-461 Document Control Desk

. Nuclear Regulatory Commission .

Washington, D.C. 20555

Subject:

Illinois Power's (IP's) Response to Generic Letter (GL')

97-04, " Assurance of Sufficient Net Positive Suction IIcad for Ilmfigency Core Coolina and Containment litaLR3moval Pumos"

Dear Madam or Sir:

This letter provides the IP 90 day response to GL 97-04. GL 97-04 requires that addressees submit information necessary to confirm the adequacy of the net positive suction head (NPSII) available for emergency core cooling (including core spray and decay heat removal) and containment heat removal pumps. Addressees are required to respond with the following information within ninety days from the date of this generic letter. Listed below is the information request in bold followed by IP's response.

1. Specify the general methodology used to calculate the head loss associated with the ECCS suction strainers.

The calculations for determining the available NPSII for Clinton Power Station (CPS) Emergency Core Cooling System (ECCS) pumps were included in the /

original pipe sizing calculations for each of the Emergency Core Cooling Systems. The analyses were performed in accordance with Regulatory Guide f[to/

1.1," Net Positive Suction IIead for Emergency Core Cooling and Contaime.ent lleat Removal System Pumps." The analyses assumed a 212'F suppression pool temperature with no credit taken for containment overpressure. The analyses ar,sumed the ECCS sminers were 50 % clogged with a resultant 1 foot head

. loss through them. This assumption was consistent with the ECCS suction strainer purchase specification requirement that specified the head loss through the strainer when 50% clogged was not to exceed 1-foot.

~

9901060258 971229 PDR ADOCK 05000461 P PDR VUJ ,

.- e .U e s96-Page 2 7

2- Identify the' required NPSH and the available NPSH.

Thc General Electric (GE) Process Diagrams for the CPS Emergency Core Cooling Sys.oma specify a NPSH requirement of 5 feet at a reference elevation of 2-feet above the pump mounting flange for each pump. Review of the vendor pump performance curves shows the actual NPSH requirements to be

approximately 2-feet at a reference elevation of 2 feet above the pump mounting .

' flange. Bounding analyses performed using preoperational test data prepared in response to_NRC Infonnation Notice 97-27, "Effect ofIncorrect Straine- Pressure l

- Drop on Available Net Positive Suction Head," show that the minimum availabic NPSH for ECCS pumps during design basis events will be greater than 9.7-feet.

[ 3. Specify whather the current design-bcsis NPSH analysis differs from the most recent analysis revieaed and approved by the NRC for which a sarety evaluation was issued.

Bounding analyse = were recently prepared usmg preoperationtJ test data during l IP's review of Nh l Infennation Notice 97-27. The analyses are based on

preoperational wst data in which the suction strainers were covered with a hood to simuiste a 50% clogged strainer. These recent analyses differ fron the analysis .

used by the NRC for issuance ofNUREG-0853. "St ' Evaluation Reoe i Related to the Operation of Clinton Power Statior. ' . t No.1," issi < . .

1982. That analysis was based on the original pipe usag calculati 4 -

l actual operating test data was used for input. The recent boundh - -

were

, performed in accordance with Regulatory Guide 5.1 guidelines. Th sasic equation used in the bounding analyses is shown na Attachment 2.

! However, the recently pe6crmed bounding analyses do not replace the Clinton L Power Station design-basis NPSH analysis. rherefore, the current C!inton Power Station design basis NPSH analysis does not differ from the most recent analysis

- reviewed and approved by the NRC for which a safety evaluation was issued.

3-

4. Specify whether containment overpressure (i.e., containment pressure above the vapor pressure of the sump or suppression pool fluid) was credited in the calculation of available NPSH. Specify the amount of overpressure needed and the rainimum overpressure available.

I No credit was taken for contair nent overpressure in either the original or the most current NPSH bounding analyses.

5. When 2ontainment overpressure is credited in the calculatica of available r NPSH, confirm that an eppropriate containment pressure analysis was done to establish the minimo containment pressure.

}

Not applicable to CPS since credit is not taken for cor,tainment overpressure.

4 N,m. v.w,, . , < -,

,,ar, , y - , _ , _ ,

, ~ _ , , _

, __4

~'

>- - ,;.i 11-602896 Page 3

. Attachment I provides'an affidavit supporting the facts set forth in this letter, Sincerely yours,'

lW ohn G. Cook Senior Vice President -

JSPirrk ,

Attachments cc: NRC Clinton Lic:nsing Project Manager NRC Resident Office, V-690 Regional Administrator, Region III, USNRC lilinois Department ofNuclear Safety t.

t

~-

.-- Attachment I to U-602896 John G. Cook, being first dulf sworn, depows and says: That he is Senior Vice President of the Nuclear Program at Illinois Power; that this letter supplying information for Generic

. Letter 97-04 has been prepared under his supervision and direction; that he knows the

contents thereof, and that to the best of his knowledge and belief said letter and the facts contained therein are true and correct. .

Date: This N day ofDecember 1997.

Signed: A I V John G. Cook STATE OFILLINOIS l SS. ~ " " = = = ^

g ' OFFICIAL SE)y, a

Mctuel D. S:t:Wy DeNitt COUNTY J  ; Notary Put!!c, St to of glinois

[ My Comm!:f:.5 Expires 2/22/99

• = = ~ ... ,., _ ,,._____ , ___

Subscribed and sworn to before me t>b ,2f_ day of December 1997.

[(Notary'Publip) 4

. N* Attachment 2 :

U 602896 Provided below is the general equation used by IP for confirming the adequacy of the net positive suction head (NPSH) available for emergency core cooling (including core spray and

- decay heat removal) and containment heat removal pumps.

NPSH.,. = [(P + P )/di + P./d2]

• 144 + V 2/2g + Z - R (He - H,)

where, NPSH = the available NPSH at runout under accident conditions P, = gauge pressure during testing at pump suction di = H2O density at test conditions d2 = H2O density at accident conditions P, = atmospheric pressure V = fluid velocity at design flow rate Z = pressure gauge elevation above the pump mcunting flange R = reference elevation above pump mounting flange for the minimum NPSH requirement a P. = saturation pressure of 212 'F water '

, Hg= suppression pool elevation during accident Hp = minimum supression pool elevation during accident .

~&

4 l

% _ _ . . _