ML18040A329

Provides Followup to Meeting W/Util & NRC on 980128 Re Reportability of Blowout Panel Deficiencies

ML18040A329
Person / Time
Site:	Nine Mile Point
Issue date:	02/19/1998
From:	Mueller J NIAGARA MOHAWK POWER CORP.
To:	Collins S NRC (Affiliation Not Assigned)
References
NMP1L-1288, NUDOCS 9802260261
Download: ML18040A329 (8)

Text

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ACCESSIOl.". 5lBR:9802260261 DOC.DATE: 98/02/19 NOTARIZED: NO DOCKET FACIL:50-220 Nine Mile Point Nuclear Station, Unit 1, Niagara Powe 05000220 AUTH.NAME AUTHOR AFFIL1ATION MUELLER,J.H. Niagara Mohawk Power Corp; RECIP . NAME RECIPIENT AFFILIATION COLLINS,S.J.

SUBJECT:

Followup to NRC. staff 980128 meeting re reportability of blowout panel deficiencies. C DISTRIBUTION CODE: IE01D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: General (50 Dkt)-Insp Rept/Notice of Violation Response NOTES:

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/5RPM PECB 1 NRR/DRPM/PERB 1 NUDOCS-ABSTRACT 1 OE DIR 1 OGC/HDS3 1 RGN1 FILE 01 1 EXTERNAL: LITCO BRYCEiJ H NOAC NRC PDR NUDOCS FULLTEXT D

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Niagara Mohawk ~ . ~

John'H. Mueller Otha t315) 3l9.7907 Fax: t315)3l9-1321 Senior NcePnmM and Chief Nudear ORer OEll8t lnuSIOrofklXLCRl February 19, 1998 NMP1L 1288 Mr. Samuel J. Collins Director, Office of NRR "U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 RF.: Nine Mile Point Unit 1 Docket No. 50-220

Subject:

Notice of Violation II.B Dated June 1S, 1996

Dear Mr. Collins:

This letter is a followup to the meeting between Niagara Mohawk Power Corporation (NMPC) and NRC staff on January 28, 1998 regarding reportability of blowout panel deficiencies.

Once again, thank you for the opportunity for NMPC to have this dialogue with you and other NRC staff regarding the important issue raised in the subject violation and subsequent correspondence between'MPC and the NRC..As we stated at the meeting, NMPC does not as a matter of course argue a level 4 violation to the extent we have in this case. However, we believe the ramifications of accepting the violation are significant to NMPC and the nuclear industry.

As we agreed at the conclusion of the meeting, we are providing this letter to summarize key points'that NMPC made during the meeting. Following are the bases for our disagreement with the violation:

I This guide was used in preparing the Nine'Mile Point Unit 1 (NMP1) Final Safety Analysis Report (FSAR). The General Consideration section of the guide presents the hierarchy of principle criteria for design, design bases and how the plant meets the plant performance objectives. As we indicated in the meeting with the example for

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Page 2 the Containment System, the Design Bases. section of the FSAR was intended to define the principle functions that are needed to protect public health and safety. This guide also provides insight into the true intent of 10CFR50.2 which was issued at about the same time. In addition, the guide separately describes design features of the containment structures and the explanation for their selection which should be in the FSAR. That guidance clearly distinguishes between design bases and design features.

When the NMP1 FSAR was developed, it was formatted so that the design features were subsections of the Design Bases section. The format could have been a separate section for design features which would have clearly distinguished between the two aspects. It is NMPC's considered opinion that the blowout panels are a design feature, whose primary function is to protect the building superstructure. The'key parameter in performing that function is to maintain internal pressure below 80 psf. NMPC believes that the guide better defines what was intended to be design bases than what was

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formatted in the NMP1 FSAR. Finally, it seems inappropriate to consider design bases to be a term such as "approximately 45 psf ".

The language in 10CFR50.72(b)(1)(ii) clearly indicates that a one hour report is needed d (000)(70.73(l(3)(")30d2 j ( ~ 'Hy 3 outside the design bases g jQ~lanl. The event for which we are cited did not, at the time, involve any serious degradation or being outside the design bases of the plant as described above.

As we stated, it is NMPC's practice to report under 10CFR50.72(b)(1)(ii) when we are uncertain whether a deviation is outside of the design bases in order to prevent possible violation of the regulation. Ifafter subsequent review it is determined that the design bases is not encroached and therefore not reportable, that notification is retracted.

When the wrong sized bolts were found in the blowout panels, the engineers involved determined, based upon engineering judgment, that the blowout panels would have relieved below 80 psf. Therefore, the event was not reported.

The statements of considerations when 10CFR50.72 and 10CFR50.73 were developed and revised indicate the rules were intended for

. In addition, the statements of considerations indicate a loss of safety margins that apply to individual components is not reportable.

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r NMPC does not believe that this deficiency in the blowout panel needed immediate action by the NRC. The deviation was a change in a setpoint of a single component with no reduction in safety margins as the internal pressure would remain below 80 psf.

Reporting.was accordingly not required.

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I sl An example in NUREG 1022 which we believe is analogous to the blowout panel is on page 37 of the second draft of Rev. 1. That example discusses initial reporting of a missing high energy line break pipe restraint which was then retracted after analysis showed that the design bases had not been exceeded. Based upon familiarity with our own and industry practice, such an analysis would almost certainly involve evaluation of piping and pipe support stresses. Ifthe analysis demonstrated code allowable stresses were not exceeded, the condition. would not be outside of the design bases of the plant.

The Reactor Building and Turbine Building structural design bases is 80 psf, which is analogous to a code allowable. The blowout panels relief analysis determined that 45 psf had been exceeded, however, the design allowable (80 psf) had not been exceeded.

The preceding summarizes the arguments made during our meeting on January 281998. One additional point of clarification made during the meeting was that Mr. Thadani's letter on September 12, 1997 alludes that'80 psf is the failure point of the Turbine Building and Reactor Building. As demonstrated by analysis, the failure point of both buildings is well in excess of 100 psf.

Very truly yours, ohn H. Mueller Chief Nuclear Officer JHM/GJG/cmk xc: Mr. H. J. Miller, Regional Administrator, Region I Mr. B. S. Norris, Senior Resident Inspector Mr. S. S. Bajwa, Director, Project Directorate I-l, NRR Mr. D. S. Hood, Senior Project Manager, NRR

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