ML13032A127

from Josephine Ambrosini to Tom Setzer: Uhs Basis Info

ML13032A127
Person / Time
Site:	Millstone
Issue date:	08/16/2012
From:	Josephine Ambrosini NRC/RGN-I/DRP/PB5
To:	Thomas Setzer NRC/RGN-I/DRP/PB5
References
FOIA/PA-2013-0045
Download: ML13032A127 (3)

Text

Setzer, Thomas From: Ambrosini, Josephine Sent: Thursday, August 16, 2012 10:26 AM To: Setzer, Thomas

Subject:

UHS basis info Attachments: U2 FSAR Chapter 14 selections.docx Looks like 77 is the design basis starting point for U2, according to their FSAR accident analysis section. I'm attaching a couple of pages copied from the FSAR.

The tech spec appears conservative and able to be changed from the 24-hour 75 degree value, but they still have some engineering work to do. For example, are there any plugged tubes in heat exchangers that would be ok with 75 degrees, but not ok with 77? That sort of thing.

I'll verify U3 has the same info in their FSAR if he wants it, but really this is NRR's job when Millstone comes in with an amendment request, not ours.

I don't have a fundamental problem with their licensing approach on this issue. Should they have done this long before now? Probably, but I don't see any technical concerns with what they are doing, provided they finish the analysis. Whether we allow them to do this in an emergency/exigent setting is, as they say, above my pay grade.

Jo Ambrosini USNRC Region I Senior Resident Inspector, Millstone 860-447-3170

U2 FSAR Chapter 14 MPS-2 FSAR TABLE 14.8.2-2 lITIM.AL CO_-NDITIONS FOR PRESSURE .N.ALYSES Reactor Coolant System NSSS power level (MWt) 13.1 0% plus pump heat of 17.1 MWt Coolan pressure (pske) 2300 Inle coolant temperature ( F) 534.25 lasemil coolant volume (cubic fet) (ehcludes the plessurier) 10.104-4 containment System Pressre q~ia)15.7 Relatve humidity ()25 aside temperature (T) 120 OuLde temperaturem f) 100 Service Water Inlet temperature (T) 77 Refieling Water Storage Tank (RWST) water temperature (CF) 100 SafetY Injection Tank (SIT) water temperature (,F) L20 Pave 1 of Rimr. 21 1

U2 LOCA Analysis M]PS-! FSAR

b. Initial c prsure is 15.7 psia.

c. Initial couainuneut buniditv is assumed toWb 25 percent as in, the MSLBý

d. The m-. mu usable Ref£ein Water Storage tank (RWST) volume assumed for alcaula*twn of the nimof Sucup Reciu-lahion Actuation Sigl (SILAS) i. 298.300 trallonsL

e. Both the HYSI and tie LPSI pumps operate prior to SEAS. Following SRAS. the 1_PSl are mtomatically stopped.

f The Reactr Building Closed Cooling Water (RBCCW) is modeled with assumed flows. before and aSff SEAS. The RBCCW is cooled bly' Senvie Warner at 77$F 7 The heat removal fim the CAR fan cooler is modeled in the CONTRANS Code.

It takes mto accouw the steam latent heat and te sensible beat removed from the contamment atmosphere.

14.3.2.4 Results The limiting LOCA was determined to be the double-ended discharge leg slot break inthte LOP.

the failure of two CAR fans and owe spray hUm. and mnmum ECCS. The maximun contanment pressure and rempersare of thi limiting LOCA are bounded by the MSLB results provided in secrion 14.8.2.1.

14.9.2.2.5 Conlusion The maximum containment pressure and temperature of the LOCA are les than the containment design pressure and temperatue of 54 psig and 2890.

14.8.3 DELETED 14.8.4 RADIOLOGICAL CONSEQUENCES OF THE DESIGN BASIS ACCIDENT 14.8.4.1 General A LOCA would increase the pressure m the containment resulting in a containment isolation and initiatin of the ECCS and countament spray systens. A SIAS sigal autmatically starts de Enclosure Buld Fitrati Synstem (F.S) which maintams a neptive presure within toe enclosure building durim accident conditions. The nuclide imventory assumed to be initially available for release is consistent with the requirements of Regulatory Guide 1.1S3 (Refereme 14.3- 5). A SIAS also isolates the control room by dosing the flesh air damper within 20 seconds.

Within I hou after control room isolation, the control room nergency, ve*ilation (CREV) is properly aligned, CREV recirculates air within the control room thuough a charcoal filter at 2-500 cfh (+/-10%) to remove iodines from the control room envelope.

14.3-8 Ret. 25.1