ML20213F015
| ML20213F015 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 11/07/1986 |
| From: | Hunsader S COMMONWEALTH EDISON CO. |
| To: | Harold Denton NRC COMMISSION (OCM) |
| References | |
| 2371K, NUDOCS 8611130417 | |
| Download: ML20213F015 (4) | |
Text
S I
-,N Commonwealth EcIleon A
One First Nabonal Plaza. Chicago. Illinois Address Reply to: Post Omco Box 767 Chicago, lilinois 60690 0767 November 7, 1986 Mr. Harold R. Denton U.
S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C.
20555
Subject:
Braidwood Station Units 1 & 2 Emergency Core Cooling System Operability NRC Docket Nos. 50-456 and 50-457 Reference (a):
J.
L. Tain letter to J. D. Deress dated November 3, 1986, regarding Safety Injection Pump Flow Rates.
Dear Mr. Denton:
The purpose of this correspondence is to inform your office of the results of the SI flow balance test when compared to Technical Specification 4.5.2.h.
The preoperational test involved, BwPT EF-ll, was completed successfully in May, 1986.
The test results have been reviewed and approved by the Test Review Board.
This test verifies that sufficient flow and NPSH are available to enable the ECCS systems to perform their safety-related functions.
Technical Specification 4.5.2.h states in part that, following any modification to the system which would alter the flow characteristics, a flow balance test must be performed.
One parameter of this post-modification flow balance is a maximum flow rate of 655 gpm.
During the preoperational testing, the 1A SI pump had a recorded flow of 656.6 gpm.
The basis for the maximum flow rate limitation arises from
,~
pump protection concerns.
As noted in the reference (a) (attached),
the 655 gpm limit is overly conservative.
A more realistic upper limit is 665 gpm.
Braidwood will propose a change to the Technical Specifications in the future to raise the maximum allowable flow i
rate based upon reference (a).
Braidwood has determined that the ECCS system can be declared operable based on the following:
i The minimum flows assumed in the FSAR Chapter 15 analyses have been met or exceeded, gol i
'D i
kh0CK05000456 17 861107 DR P
. No technical concerns related to pump integrity exist, As noted in the FSAR and Section 14 of NUREG 0876, successful completion of the preoperational tests is sufficient to demonstrate that the system is capable of meeting its safety-related performance requirements, and The surveillance requirements of Specification 4.5.2 are not applicable until such time as the system is modified in a manner that would alter the flow characteristics.
This concern has been discussed with the Resident Inspectors and verbal concurrence that no technical concerns exist has been obtained.
If there are any questions in this matter, please contact this office.
Very truly yours, Cf w b S.
C. Hunsader Nuclear Licensing Administrator SCH/rmg att.
cc: NRC Resident Inspector - Braidwood
(
J.
Stevens 2371K l
l
.n,-.
t..a-
/
N I
\\v/
1.,.
Westinghouse Power Systems Systems Dmsion Electric Corporation Bc 355 Pittsburgh Pennsytvania 15230 0355 CBW-5697 DATE: November 3,
1986 Mr.
J.
D.
Deress S.
O.
NO: CCE/CDE-280 Project Engineering Manager SET-CCE-308 Byr on & Braidwood Projects Commonwealth Edison Company P.
O.
B o>: 767 Chicago, I111 noi s 60690 COMMONWEALTH EDISON COMPANY BRAIDWOOD STATIONS - UNITS 1 AND 2 Safety Injection Pump Flow Rate
Dear Mr. Der ess:
This l et t er documents the justification for al l owi ng the intermediate head safety injection pump to be operated at a flow rate of 665 gpm against atmospheric pressure in the cold legs.
The f1ow rate has been requested as the revised basis for the maximum al1owable f1ow in Section 4.5.2.h.2.b of the Braidwood Tech Specs.
Currently 655 is the flow rate in Section 4.5.2.h.2.b of the Tech Specs.
The reason for the flow being higher than 655 gpm is the fact that the Braidwood combination of intermediate head safety injection pumps has 1 pump that is noticably stronger than its " sister" pump.
Westinqhouse concurs with this Tech Spec change proposal for the following reasons:
a.
The F5AR Chapter 15 safety analyses flow rates are exceeded.
The weal'er intermediate head pump meets Westinghouse minimum head and flow specifications and thE systen. Is properly balanced.
Havano an intermediate head s.afety injection pump stronger than minimum specification and more safety injection flow of this magnitude has negligible effect on safety (Note: Westinghouse does. not condone increasing the maximum allowable charging pump flow r ate in the Tech Specs),
b.
Ava11able net positive suction head (NP5H) is satisfactory.
The required NPSH curve plotted on the certified pump curve is stable at the last measured head / flow i
point, and other plant specific intermediate head pump curves show stable NPSH requirements at 665 gpm-below the NP5H i
i
]
,o N_.
o avalleble at the Braidwood plant.
The Br al dwood 1B safety injection i ntermedi ate head pump has been run by Pac 2fic Pumps at 665 gpm.
c.
Attual intermediate saiety 2njection pump fIow rates during full safeguards actuation for a double ended breal (man 2 mum i nter medi ate saf et y injection pump flow condition) will be lower than the f low rate demonstrated in the pr e-oper at 2 onal test or any future t ur ve111 ance.
This as due to the additionel pipe friction in the common refueling water stor age tsnt di scharge pipe and add 2 ti onal friction in the 10 inch accumuletor di scharge piping due to simultaneous additional flow from the accumulator tanks and low head safety injection system that share common piping connected to each told leg.
The Braldwood EF-11 pre-operational test confirms that the intermediate head safety injection pump flow i s bel ow 655 ppm during single train safeguards actuation--even without simultaneous accumul ator injection.
If you have any questions, please contact us.
Very truly yours, WESTINGHOUSE ELECTRIC CORPORATION
'in 6&atr J.
L.
aln, Maneger Commonweelth Ed2 son Frojects J.
D.
De'ess, 2L. 2A cc:
W.
C.
Clefi 2L, 2A b/L Chiceco
,-