ML20202H759

Forwards Draft Request for Addl Info Re Radiological Consequences of Steam Generator Tube Rupture

ML20202H759
Person / Time
Site:	Millstone
Issue date:	02/01/1999
From:	Stephen Dembek NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
TAC-MA4175, NUDOCS 9902080221
Download: ML20202H759 (3)

Text

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i February 1,1999 f MEMORANDUM TO: Docket File FROM: Stephen Dembek, Project Manager Project Directorate 1-2

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Division of Reactor Projects - l/ll ,

l Office of Nuclear Reactor Regulation l

SUBJECT:

MILLSTONE NUCLEAR POWER STATION, UNIT 2, DRAFT REQUEST l

FOR ADDITIONAL INFORMATION, RADIOLOGICAL CONSEQUENCES i OF STEAM GENERATOR TUBE RUPTURE (TAC NO. MA4175) l l

The attached request for additionalinformation (RAI) was transmitted by facsimile on February 1,1999, to Ravi Joshi of the licensee's staff. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI and/or clarify issues that may not need a formal response from the licensee. This memorandum and the attachment do not convey a formal request for information or represent an NRC staff position.

Docket No. 50-336

Attachment:

As stated DISTRIBUTION Docket File I

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, , , , , #p February 1,1999 MEMORANDUM TO: Docket File l

FROM: . Stephen Dembek,. Project Manager Project Directorate 1-2 l Division of Reactor Projects -l/ll I

Office of Nuclear Reactor Regulation i

SUBJECT:

MILLSTONE NUCLEAR POWER STATION, UNIT 2, DRAFT REQUEST

FOR ADDITIONAL INFORMATION, RADIOLOGICAL CONSEQUENCES OF STEAM GENERATOR TUBE RUPTURE (TAC NO. MA4175)

The attached request for additional information (RAI) was transmitted by facsimile on February 1,1999, to Ravi Joshi of the licensee's staff. Review of the RAI would allow the licensee to determine and agree upon a schedule to respond to the RAI and/or clarify issues l

that may not need a formal response from the licensee. This memorandum and the attachment do not convey a formal request for information or represent an NRC staff position.

Docket No. 50-336

Attachment:

As stated r

i

pRAFT Q u i=mAM

- 1. In your submittal you state that the air ejector release path to the Unit 1 stack will be automatically isolated upon isolation of the EBFAS and the vent path will be manually realigned to the Unit 2 stack.

1. Provide the EAB and LPZ X/Q values which you used for the Unit 1 stack release.

2. Provide the time interval following the tube rupture that 1) the automatic isolation of the Unit 1 stack occurs and 2) the release from the Unit 2 stack begins.

3. State the time required for realignment of the air ejector release path from the Unit 1 stack to the Unit 2 stack. Where do you assume the release path to be during this period of manual realignment (or do you assume that releases are stopped during this period)?

2. In your submittal you pronose eliminating the X/Q values for an elevated release and reducing the X/Q values for a ground level release. Justify your reasons for proposing these changes. Justify your reasons for using a ground level release X/O value (EAB of 3.66 E-4 and LPZ of 4.8 E-5) for releases from both the Unit 2 stack (via the condenser air ejector discharge), and for releases from the atmosphere dump valves and the safety valves.

3. In your submittal you state that one of the changes used in the updated dose consequences calculation is the inclusion of the potential of flashing of the primary-to-secondary leakage in the ruptured (faulted) SG. If you accounted for flashing of a fraction of the primary-to-secondary leakage to the faulted SG in your updated dose analysis:

1. Provide a table listing the flashing fractions in the faulted steam generator (Ib flashed /lb break flow) as a function of time following the SG tube rupture.

2. Provide a table listing the break flow rate (Ib/sec) to the faulted SG as a function of time following the SG tube rupture.

3. Provide the scrubbing fraction used for the faulted SG.

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