ML20059K735

Application for Emergency Amend to License DPR-30 for NRC Review & Approval of Two USQs Associated W/Interim Mod on Quad-Cities Station Unit 2,to Resolve Concerns Described in NRC Bulletin 93-003

ML20059K735
Person / Time
Site:	Quad Cities
Issue date:	01/14/1994
From:	Schrage J COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
IEB-93-003, IEB-93-3, NUDOCS 9402020235
Download: ML20059K735 (5)

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b y January 14,1994 Dr.-Thomas E. Murley .

Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission ~

Washington D.C. 20555 Attn.: Document Control Desk

Subject:

Quad Cities Station Unit 2 Request for Emergency License Amendment  :

Facility' Operating License DPR-30  :

NRC Docket No. 50-265 -)

References:

(1) P.L. Piet to T.E. Murley letter dated October 29,1993. 1 C.P. Patel to D.L. Farrar letter dated November 3,1993-

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(2) I!

(3) J. Stang to D. Farrar letter dated November 25,'1993 ,i (4) L.O. DelGeorge to T.E. Murley letter dated December 22, [

1993. ,

(5) Teleconference between CECO (J. Schrage, P. Piet) and the L

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ti NRC (C. Pate!) on January 13,1994.

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(6)' Teleconference between CECO (D. Farrar) and the NRC (J." ,

Zwolinski, et all on January 14,1994. 9 Dr. Murley, This letter requests an Emergency License Amendment for the NRC review and approval of two Unreviewed Safety Questions (USQs) associated with an interim~

modification on Quad Cities Station Unit'2C This interim modification will resolve 'l concerns described in NRC Bulletin (IEB) 93-03, " Resolution of Issues Related to Reactor Vessel Water Level instrumentation in BWRs" until a long term modification is; -

implemented on Unit 2 during the thirteenth refuel outage (O2R13). The' basis for this.' j Emergency License Amendment is described below. '

. On October 29,1993, (ReferenceL(1)), CECO submitted proposed License .. .

Amendments for the resolution of two Unreviewed Safety Questions (USQs) for Quad : '

Cities Station Units 1 and 2, and Dresden Station Units 2 and 3. These USQs were:

L  ; associated with modifications which re' solved concerns described in NRC Bulletin (IEB) 93.

03, Resolution of issues Related to Reactor Vessel Water Level Instrumentation in. l BWRs." ' in addition, CECO ~ requested NRC review and approval for Quad Cities Station '

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Dr. T.E. Murley January 14,-1994 j e

Unit 1 on an Exigent Basis to support installation of the modification during a planned maintenance outage in November 1993. The NRC Staff forwarded the " Notice of Consideration of issuance of Amendment to Facility Operating License" (for the Quad l Cities Unit 1 proposed Exigent License Amendment) to the Office of the Federal Register j on November 3,1993 (Reference (2)). ,

The proposed Amendment would provide NRC review and approval for two  !

Unreviewed Safety Questions (USQs) associated with an interim modification for Quad j Cities Station Unit 2. The interim modification resolves the concems described in NRC 1 Bulletin (IEB) 93-03, " Resolution of issues Related to Reactor Vessel Water Level ,

Instrumentation in BWRs."

On November 25,1993 (Reference (3)), the NRC Staff responded to the Reference (1) letter, and instructed CECO not to implement Reactor Vessel Level Instrumentation System (RVLIS) modifications which require administrative controls. The NRC Staff also requested a 30-day response from CECO to provide a descriptiun and implementation s schedule for modifications at Dresden and Quad Cities Stations which would resolve the f issues described in NRC Bulletin (IEB) 93-03 without relying on administrative controls.

i CECO responded to the NRC Staff's request on December 22,1993 (Reference  ?

(4)), with a description and proposed schedule for implementation of RVLIS modifications which did not rely upon admirestrative controls. As part of the proposed schedule, CECO i described a proposed interim modification for Quad Cities Unit 2 which was planned for i installation and operation prior to start-up following the current maintenance outage (O2M11, scheduled to initiate startup on January 21, 1994). CECO also indicated that implementation of this interim modification would require NRC review and approval of the two USQs which had been previously submitted in Reference (1).

On January 13,1994, CECO identified that the proposed License Amendment for _d Quad Cities Unit 2, which was originally submitted on October 29,1993, had not been noticed in the Federal Register. During a teleconference on January 13,1994 with CECO ]

(Reference (5)), The NRC Staff confirmed that the proposed License Amendment for Quad Cities Unit 2 had not been noticed in the Federal Register.

On January 14,1993 (Reference (6) teleconference), the NRC Staff informed-CECO that the proposed License Amendment for Quad Cities Unit 2 could not be approved j

prior to startup, and the Staff requested CECO to submit a request for an Emergency License Amendment for Quad Cities Station Unit 2. Therefore, in order to support startup of Quad Cities Station Unit 2 with the interim RVLIS modification operable (to address the concerns identified in NRC Bulletin (IEB) 93-03), CECO requests that the NRC grant an Emergency License Amendment for review and approval of the two Unreviewed Safety Questions associated with the interim modification.

The Federal Register Notice for the Quad Cities Unit 1 proposed License Amendment (Reference (3)) is identical to the proposed License Amendment for Quad  !

Cities Unit 2. )

l In addition to the request for an Emergency License Amendment for Quad Cities  !

Unit 2, this letter provides additional information with respect to the leakage criteria for

Dr. T.E. Murley January 14,1994 the safety-related backfill instrument line check valves. This information is provided in the 'l Enclosure to this letter. i To the best of my knowledge and belief, the statements contained above and in the Encilosure are true and correct, in some respects, these statements are not based on my personal knowledge, but upon information furnished by other Commonwealth Edison and contractor employees. Such information has been reviewed in accordance with company practice, and I believe it to be reliable.

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If there are any further questions, please contact John L. Schrage at 708-663-7283.

Very truly urs,

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! ' i Joh L. Schrage f uclear Licensing Administrator Enclosure

cc: J. Martin, Regional Administrator-Rill T. Taylor, Senior Resident inspector-Quad Cities ,

C. Patel, Project Manager-NRR Office of Nuclear Facility Safety -IDNS  ;

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ENCLOSURE LEAKAGE CRITERIA AND CALCULATIONAL METHODOLOGY QUAD CITIES STATION BACKFILL INSTRUMENT CHECK VALVES

1. What is the leakage criteria for the backfill instrument check valves at Quad Cities Station?

Quad Cities has calculated the critical seat leakage rate for the RVLIS backfill instrument check valves to be 30 ml/hr. To increase the margin of safety, CECO has established a maximum test leakage rate of 3.0 ml/hr for the RVLis backfill check valves. This provides significant leak rate margin for assurance that instrument accuracy will be maintained.

2. How was the leakage criteria derived?

l Leakage criteria was established to provide assurance that vessellevel instrumentation integrity is adequately maintained in the event of CRD system l

depressurization. The basis for the check valve leakage shall be the maximum leakage which ensures that the loss of water inventory from the reference leg piping over an acceptable time period is limited to that corresponding to a 6" level change.

This ensures that adequate vessel level indication is provided to the operator for assessing plant operating conditions.

The level change criteria (six inches) is based upon the total instrument calibration tolerance from sensor to control room indicator. The time criteria (ten hours) is based upon the detection of a level gauge discrepancy by the control room operator within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, and implementation of corrective actions (isolation of the potentially leaking backfill system) within an additional 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

Based upon the inputs described above, CECO determined the volume of water, in the condensate pot and reference leg, that would provide, if lost, a 6" level discrepancy. This value was then divided by 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />. This yielded a critical seat' leakage rate for the RVLIS backfill instrument check valves of 30 ml/hr. However, in order to increase the margin of safety, CECO has established a maximum test leakage rate of 3.0 ml/hr, which is a factor of 10 less than the critical seat leakage.

The RVLIS backfillinstrument check valves will be periodically tested as part of the IST program.

The Quad Cities Station IST program is committed to the 1986 Edition of ASME Section XI. Per this code, the leakage rate for check valves will be " owner supplied", or as calculated using the following formula,2*30*D (ml/hr), where D is the check valve nominal valve size.

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. i CECO has developed an " owner supplied" value, based upon the information above, I of 3.0 ml/hr. Using the ASME formula (2*30*D), CECO calculated a leakage rate criteria of 22.5 ml/hr. l

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3. Provide the basis for acceptability of the leakage criteria. .i I

This adjusted leakage critoria is in compliance with ASME Section XI, and is

> conservative to the critical seat leakage for the RVLIS backfill instrument check . ,

valves.

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