ML20154E866
| ML20154E866 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 10/05/1998 |
| From: | Rainsberry J SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-04, GL-97-4, TAC-MA0040, TAC-MA0041, TAC-MA40, TAC-MA41, NUDOCS 9810090010 | |
| Download: ML20154E866 (3) | |
Text
il l h SDUIHE RN CAL H ORMA - !
B" ' EDISON * "'
'"", Plant Licensing Manager An EDISON INTERNATIOM4l* Company e ,.
October 5, 1998 U.S. Nuclear Regulatory Commission
-ATTN: Document Control Desk Washington, D.C. 20555-0001 l
Gentlemen: - j
Subject:
NRC Generic Letter 97-04: Assurance;of Sufficient Net Positive Suction Head for Emergency Core Cooling and_ Containment Heat Removal Pumps !
San Onofre Nuclear Generating Station Units 2 and 3 (TAC Nos. !
MA0040 and MA0041)
References:
- 1) August 19, 1998 letter from James W. Clifford (NRC) to Harold l B. Ray (SCE),'
Subject:
Request for Additional )
Information - San Onofre Nuclear Generating Station Units 2 and 3:(TAC Nos. MA0040.and MA0041) j
- 2) January 2, 1998 letter from J. L. Rainsberry (SCE) to Document Control Desk (NRC),
Subject:
NRC Generic Letter 97-04: Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps, San Onofre Nuclear Generating Station Units 2 and 3 This letter provides the additional information requested in Reference l' ,
concerning NRC Generic Letter (GL) 97-04. This information confirms the l adequacy of- the net positive suction head (NPSH) available for emergency core
. cooling and containment heat removal pumps at San Onofre Units 2 and 3. In addition to the information requested in Reference 1, a correction to ,
' Reference 2, Southern California Edison's (SCE's) initial response to GL !
97-04, is provided below. The NRC questions in Reference 1 and SCE responses are the following: {
NRC Question 1:
What is the maximum sump temperature assumed in the net positive suction head (NPSH) analysis? ;
SCE Response: \g The maximum sump temperature assumed in the NPSH analysis (Calculation M-0012-010) is 270 degrees F.
San Onofre Nuclear Generating Station P. O. Box 128
,o.
UiU( u) hoh San Clemente. CA 92674 0128 ,
9810090010 981005r !
PDR ADOCK 05000361 P POR
a
!' - Document Control Desk ;
NRC Question'2:
Tables 1, 3, and 4 in the GL response (Reference 2) list the NPSH i l required for the containment spray pumps as 13 feet. However, the !
flowrate provided in Tables 1 and 3 is 2200 gpm whereas the flowrate in
! Table 4 is 2500 gpm. Explain'why the NPSH required did not increase !
with the 300 gpm increase in flow.
l SCE Responset for clarification,' the flowrates provided in Reference'2 Tables 1. and 4- f are 2500 gpm (runout flow), and the flowrate in Table 3 is 2200 gpm i
! (worstcasedesignflow). l i
L The data provided in Tables 1 and 4 were taken from the NPSH calculation ,
of record, M-0012-01D, which states that the NPSH required for l Containment Spray pumps at runout flow of 2500 gpm is-13.0 ft. A review '
of the manufacturer's certified test' curves confirmed that three of the '
l four containment spray pumps (there are two at each unit) were bounded by the data presented in the calculation. For three of these pumps, the :
NPSH required 9 2500 gpm is equal to or less than 13.0 ft. However, the !
( remaining pump (2P012) requires 13.0 ft. NPSH 9 2200 gpm and 14.0 ft. .!
NPSH 9 2500 gpm. This difference is not significant due to the large margin; NPSH available is 24.5 ft. The NPSH calculation of record, ;
M-0012-01D, is an original Bechtel calculation, issued November 13, i
- 1980. SCE has added a note to the calculation documenting that 2P012 l l: requires 14.0 ft. NPSH 9 2500 gpm. !
NRC Question 3: l l Have there been any other revisions to the NPSH calculations.Other than ]
those discussed in response to question 3 of the subject Generic Letter? '
h SCE Response.
The NPSH calculation of record to date (M-0012-01D) has not been revised j other than as discussed in the response to question 3 in Reference 2 and '
< addition of the note as stated in the response to question 2 above. A l design change package (DCP-2(3)-6863.0SN) was issued in 1993 to enable the use of the Containment Spray pumps for.. Shutdown Cooling or Spent Fuel Pool. Cooling. This design change added a 16"x10" weldolet in the suction of the Containment Spray pumps. Since Containment Spray flow from the Refueling Water Storage Tank or the Emergency Safety Features 1 Sump.is straight through the run of this connection, the change was i
!. considered to have a negligible impact on the NPSH calculation, and no l
[ changes were made.
I I
fL - . . . . ._
1 l
- j. Document Control Desk !
(. .
Correction to Reference 2:
Reference 2 referenced two calculations: M12.1D and N-0024-006. The actual calculation numbers are M-0012-010 and N-0240-006, respectively.
l-If you have any questions or would like additional information, please let me j know.
q-l Sincerely, l
, s a
i
/ l
\
l cc: E. W. Merschoff, Regional Administrator, NRC Region IV l J. A. Sloan, NRC Senior Resident Inspector, San Onofre Units 2 & 3 l.
J. W. Clifford, NRC Project Manager, San Onofre Units 2 and 3 ;
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