ML20126L338

Responds to IE Bulletin 80-17,Suppls 1 & 2, Failure of 76 of 185 Control Rods to Fully Insert During Scram at Bwr. Insp Procedure Used for Scram Discharge Vol Sys,Marked Up Isometric Drawings & Quality Insp Rept Re Sys Encl

ML20126L338
Person / Time
Site:	Susquehanna
Issue date:	05/26/1981
From:	Curtis N PENNSYLVANIA POWER & LIGHT CO.
To:	Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20126L341	List: ML20126L338 ML20126L347
References
IEB-80-17, PLA-770, NUDOCS 8106020354
Download: ML20126L338 (5)

Text

U PP&L fWO NORTH NINTH $TRitT, ALLENTOWN. FA. 18101 PHONtt (215) 821 5151 NORMAN W. CURTIS ves Presg:ent.Engineenng & Consuuccon 821 5381 g ,N MAY 2 61981 rp .h U

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Mr. Boyce H. Grier, Director JUN0'l$81* '

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( Region I f U.S. Nuclear Regulatory Commission \/,. , -

631 Park Avenue

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King of Prussia, Pennsylvania 19406 q, j/ ,,

SUSQUEHANNA STEAM ELECTRIC STATION IE BULLETIN 80-17 SUPPLEMENTS 1 AND 2 '

ER 100450 FILE 842-3 DOCKET NOS. 50-387 PLA-770 50-388

Dear Mr Grier:

The following information is provided in response to IE Bulletin 80-17, Supplements 1 and 2, " Failure of 76 of 185 Control Rods to Fully Insert During a Scram at a BWR."

Supplement 1 actions to be taken:

A.1. The system verification, as required by item A.1 of Supplement l', was performed prior to system turnover. The term "as built" refers to the isometric and other drawings representing the conditions existing at the time of system verification. The following items are attached:

a. The procedure used to inspect the "as built" condition of the Unit 1 SDV system,

b. Marked-up copies of the isometric drawings and other drawings of the Unit 1 SDV system. The originals are available for

! inspection at PP&L General Offices in Allentown, t

c. The Quality Inspection Report addressing verification of the Unit 1 SDV system.

The system was reviewed against the following criteria:

a. The SDV's must have 3.34 gallons capacity per control rod drive to allow for a full acram on demand,

b. All vent lines must not allow any water pockets.

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c. The vent lines must not be submerged in the sump.

d. The vent lines must not be shared by other systems.

818602 0354

Mr. Boyce H. Grier M E 2 8 [$$f

e. The drain lines must slope down and not allow air pockets.

f. The drain lines must not be shared with other systems.

g. All valves must be positioned in the system to assure flow in the correct direction.

h. Level sensors in the SDIV's must be positioned to initiate the signal they are intended to provide.

The review had the following results:

a. The SDV's were confirmed to have in excess of 3.34 gallons capacity for'each of the 18S CRD's, above the scram level switch set point.

b. The "as-built" drawings of Unit i reveal all vent lines slope up and no " pockets" exist to the vent valves. Then the vent lines slope down, mostly vertical, to the sump area.

c. The "as-built" drawings of Unit lL reveal the vent lines discharge into the Reactor Building sump above the high level in the sump.

d. The "as-built" drawings.of Unit i reveal the vent lines of the SDV's have no interconnecting lines with other systems.

e. The "as-built" drawings of Unit I reveal the drain lines slope down.

f. The "as-built" drawings of Unit i reveal the drain lines of Unit 1 SDV's have no interconnecting lines with other systems.

There is sufficient drain line height (about 87 feet) to allow drainage of any accumulated water in the lines even if a perfect vacuum were created. This means no water could enter the SDV's via the drain lines from the sump due to a vacuum induced reverse flow.

g .- The instrument root valves for the float switches have essentially no flow and this criteria does not apply to these i valves. The drain and vent valves are placed correctly I

accordingly to the flow indication arrows on the valve bodies.

h. The float switch level chambers for low level, red block, and scram initiation are installed as designed.

A.2. Operating Procedure CP-53-001 has been revised to define, for the operator, specific plant conditions which require initiation of the SLCS. This revision is in draf t form and has been issued for information and trial use.

l Mr. Boyce R. Grier MAY 2 61981 A.3. Susquehanna's SDV's are connected to the SDIV's directly by an 8" elbow. Due to this closely coupled arrangement, water will drain to the SDIV's and will not collect in the SDV's. The SDIV's have adequate instrumentation to continuously monitor system water levels. Therefore, procedures are not required concerning water levels in the SDV's.

A.4 Check-Off Lists OP-53-001-1 (Unit 1) and OP-53-001-3 (Unit 2) require the Control Room Operator to be cognizant of the location of the SLCS initiation key. These check-off lists have been drafted and will be issued upon system turnover. A key will be administratively controlled in the shift office to allow rapid access..

A.S. Susquehanna has an integral SDV/SDIV design which precludes the need for a separate continuous monitoring system. The float switches with their respective alarm, control, and RPS functions are adequate and alleviate the need for water level monitoring in the SDV's.

B.1. The SDV's do not need separate continuous water level monitors. As described above,-Susquehanna's SDV's are closely coupled with the SDIV's. This design allows the SDIV float switches to continuously monitor the water in the SDV's. SDIV "not drained" alarm, rod withdrawal blocks, and scram functions are also provided by the float switches.

In response to suggested ATWS improvements, delta pressure level switches will be installed to provide diversity for scram initiation.

Additional float switches will be installed in the south SDIV (Unit 1) for alarm and rod block. The installation of these new switches will be scheduled consistent with the overall ATWS implementation. Current schedule calls for completion of SDIV instrument additions by December 31, 1982 contingent on materials availability. Identical improvements will be made to the Unit 2 SDIV consistent with Unit 2 schedule.

B.2.

In response to item A.1~a review of Susquehanna's SDV system (including the vent paths) was performed. This review concluded that the system is adequate and will perform satisfactorily. In addition, a vacuum breaker draining thewill SDV's.

be installed downstream of the SDV vent valve to aid in Redundant parallel valves will not be installed in either the vent or the drain lines. This work will be completed on Unit 1 prior to the end of the first refueling outage and on Unit 2 prior to Fuel Load.

Supplement 2 actions to be taken:

1.

Susquehanna's present SDV vent system is dependent solely on the vent valve and piping provided. No modifications to the piping, in response to this supplement, are anticipated or necessary.

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Mr. Boyce H. Grier -

4- MAY 2 61981 Very truly yours, b '

N. W. Curtis Vice President-Engineering & Construction-Nuclear Attachments and Affidavit RMH:mcb ces Director Division of Reactor Operations Inspection Office of Inspection and Enforcement U. S. Nuclear Regulatory. Commission Washington, D.C. 20555 Mr. G. G. Rhoads U. S. Nuclear Regulatory Commission P. O. Box 52 Shickshinny, PA 18655 Mr. L. D. Narrow U. S. Nuclear Regulatory Commi-sion 631 Park Avenue j' King of Prussia, PA 19406 l

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AFFIDAVIT COMMONWEALTH OF PENNSYLVANIA)

SS COUNTY OF LEHIGH )

I, NORMAN W. CURTIS, being duly sworn according to law, state that I am Vice President, Engineericg & Construction-Nuclear of Pennsylvania  !

Power & Light Company and that the facts set forth on the attached response by i Applicants to IE Bulletin 80-17, Supplemer.ts 1 and 2, are true and correct to the best of my knowledge, information and belief.

. i Norman W. Curtis Vice President, Engineering & Construction-Nuclear Sworn to and subscribed before me this 26 M day of May, 1981.

(9-4m. 0-Notary Public JEAN A. SMOUCX, Notary Public Allentown, Lehigh County, Pa.

My Commission Dpires May 14,1984

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