ML19309A481

Forwards NRC Re NRC Conclusions Concerning Proposed Control Rod Drive Sys Mods & NRC Concerning Addl Analyses of Boiloff Rates & Control Rod Drive Sys Makeup Capability

ML19309A481
Person / Time
Site:	LaSalle
Issue date:	03/06/1980
From:	Parr O Office of Nuclear Reactor Regulation
To:	Peoples D COMMONWEALTH EDISON CO.
References
REF-GTECI-A-10, REF-GTECI-RV NUDOCS 8003310349
Download: ML19309A481 (2)

Text

f T:3 gg k

UNITED STATE 3 y'

g NUCLEAR REGULATORY COMMISSION 5 J' S E WASHINGTO*J O. C. 20555

~ t as...../

MAR 0 61980 Docket Nos. 50-373/374 Mr. D. Louis Peoples Director of Nuclear Licensing Commonwealth Edison Company P. O. Box 767 Chicago, Illinois 60690

SUBJECT:

MODIFICATIONS TO BOILING WATER REACTOR CONTROL ROD ORIVE SYSTEMS Enclosed you will find a copy of our January 28, 1980 letter to General Electric which discusses the NRC staff's conclusions regarding proposed control rod drive (CRD) system modifications related to the elimination of cracking in the CRD return line nozzle. You will also find a copy of our February 11, 1980 letter to GE regarding additional analyses of boiloff rates and CRD system makeup capability.

This. letter also responds to a GE-proposed draft procedure for optimizing GRD pump flow to the reactor vessel.

You should especially note our request tnt modifications not be performed on operating reactors until complete guidance has been issued in NUREG-0619. We anticipate issuing this document in its "For Comment" form in April 1980. However, if an operating reactor is scheduled for a rQling outage in the near future, and if applicable CRD system modifications or adjustments are scheduled prior to the final issuance of NUREG-0619, please obtain NRC guidance by contacting your Project Manager. The staff will provide assistance as necessary.

Sincerely,

%lanb.f

. Parr, D ef Light Water Reactors Branch No. 3 Division of Project Management

Enclosures:

As stated cc w/ enclosures:

See next page 8 003310 8g%

J cc: Mr. D. Louis Peoples

• cc: Richard E. Powell, Esq.

Isham, Lincoln & Beale One First National Plaza 4

2400 Chicago, I:linois 60670 Dean Hansell, Esq.

Assistant Attorney Ge..croi State of Illinois 188 West Randolph Street Suite 2315 Chicago, Illinois 60601 Mr. Roger Walker, Resident Inspector V. S. Nuclear Regulatory Commission P. O. Box 737 Streator, Illinois 61364 i

l i

l

o.

ns as,,

/a

'o, u% TED ST ATIS E

i NUCLEAR REGULATORY COMMISSION isAaMING7086. D. C. 20E85 7,

s

n. y e y

%%,,,,s.'

January 28, 1980 Generic Technical Activity A-10 Mr. Richard Gridley, Manager Fuel and Services Licensing General Electric Cogany 175 Curtner Avenue San Jose, California 95215

Dear Mr. Gridley:

Since the initial discovery af cracking in boiling water reactor (SWR) control rod drive return line (CRORL) nozzles in early 1977, General Electric (GE) has proposed a number of solutions to tne problem in the course of which several documents were submitted for hRC staff review.

These documents were as follows:

1.

Letter of March 14, 1979, G. G. Sherwood (GE) to V. Stello and R. Mattson (NRC) regarding calculation of CRD system return flow capacity; 2.

Letter of April 9,1979. G. G. Shemood (GE) to Y. Stello and R. Mattson (NRC) forwarding results of CR0 systes solenoid valve endurance testing; 3.

Letter of May 1, 1979, G. G. She mood (GE) to Y. Stello and R. Mattson (NRC) fomarding results of CRD system solenoid valve performance testing; and 4.

Letter of November 2,1979 G. G. Sherwood (GE) to R. P. Snaider (NRC) fomarding additional information as requested regarding CR0 hydraulic system perfor-nance, especially with regard to corrosion products emanating from carbon steel piping.

All concerned the GE rationale for the latest proposed system modification to prevent nozzle cracking; na:nely, total removal of the CRORL and cutting and capping of the CRDRL noz:le. Previous submittals had presented the bases for the other modification proposals discussed nerein.

y

\\q l)

(2

'gs 0 {;

c b

(#(

N s#

1. y v

((pe%

I, UNITED STATES

,5,f j NUCLEAR REGULATORY COMMISSION

.y j

wasmoros o. c. 2osss s

g

/

February 11, 1980 Generic Task No. A-10 Mr. Richard Gridley, Manager Fuel & Services Licensing General Electric Company 175 Curtner Avenue San Jose, California 95125

Dear Mr. Gridley:

By letter dated November 27, 1979, you forwarded results of analyses of boil-off rates and Control Rod Drive (CRD) System Pump makeup capability for plants not previously addressed in earlier related sub,ittals. The letter also included a draft procedure for optimizing CR0 pump flow to the reactor vessel.

The November 27, 1979 letter was not included in the NRC's Unresolved Safety Issue A-10 review and the analyzed classes of plants will not be included in NUREG-0619, which resolves A-10 and is tentatively scheduled for issuance in "For Cor: ment" form by February 29, 1930. However, we see no reason wny licensees and applicants cannot use the results in the plant-specific analyses (and testing) required by NUREG-06-19. Signi~ficantly more detail will be reNired in their submittals, however, particularly,with regard to the assump-tions utilized in derivation of the various flow rates.

We concur that the GE-proposed procedure for optimization of CR0 system flow to the pressure vessel provides a necessary first step toward reaching the desired goal.

However, in our opinion it is too cumbersome with regard to measurement of pump discharge flow. When faced with the need to maintain water level upon loss of other capable high pressure water injection systems, the operator simply cannot be burdened with the need to refer to pump curves or the need to consider what, if any, other portions of system flow are not included in a respanned flow meter.

We believe that operators should be provided one or two meters capable of reliable direct measurement of one and two pump flow.

\\

Smcerely, Yhu6 as #

N f b)

Darrell G. gisenhut, Acting Director x

Division of Operating Reactors Office of Nuclear Reactor Regulation

/ b" Q

j t

., (

qg @Nb

[f

-