View source for B11517, Forwards Util Response to SER (NUREG-1031) Open Item 10 Re Justification for Subcompartment Analysis of Only Upper Reactor Cavity,Per NRC 840802 Request.Info Should Close Item

{{Adams
| number = ML20116E425
| issue date = 04/19/1985
| title = Forwards Util Response to SER (NUREG-1031) Open Item 10 Re Justification for Subcompartment Analysis of Only Upper Reactor Cavity,Per NRC 840802 Request.Info Should Close Item
| author name = Counsil W
| author affiliation = NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
| addressee name = Youngblood B
| addressee affiliation = NRC OFFICE OF NUCLEAR REACTOR REGULATION (NRR)
| docket = 05000423
| license number = 
| contact person = 
| case reference number = RTR-NUREG-1031
| document report number = B11517, NUDOCS 8504300289
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 3
}}

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                   .am .m m.cw                                                  HARTFORD CONNECTICUT 061414270 L  t   ;  '.r* ae a       cow.                                         (203)666 6911 April 19,1985 Docl<et No. 50-423 Bl1517 Director of Nuclear Reactor Regulation Mr. B. 3. Youngblood, Chief Licensing Branch No.1 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Reference          (1)   B. 3. Youngblood letter to W. G. Counsit, Issuance of Safety Evaluation Report - NUREG-1031 - Millstone Nuclear Power Station, Unit No. 3, dated August 2,1984.

==Dear Mr. Youngblood:==

Millstone Nuclear Power Station, Unit No. 3 Response to SER Open item #10 Attached is Northeast Nuclear Energy Company's response to SER Open Item #10 concerning justification for analysis of only the upper reactor cavity which was identified in Reference (1).
We trust that this information will fully resolve the Staff's concerns regarding Open Item #10. However, if you have any further questions, please contact our licensing representative directly.
Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY et. al.
BY NORTHEAST NUCLEAR ENERGY COMPANY Their Agent
                                                                      /(&ftQ       '
W. G. Counsil Senior Vice President B504300289 850419                                                                           [IbOk hDR ADOCK 05000423                                                                                 I/
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STATE OF CONNECTICUT )
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Then personally appeared before me W. G. Counsil, who being duly sworn, did state that he is Senior Vice President of Northeast Nuclear Energy Company, an App!! cant herein, that he is authorized to execute and file the foregoing information in the name and on behalf of the Applicants herein and that the statements contained in said information are true and correct to the best of his knowledge and belief.
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d SER Open item 10 - Subcompartment Analysis (SER Section 6.2.1.2)
The applicant has stated that the design of the neutron shield tank and reactor vessel insulation prevents venting dawnward below the upper cavity. Thus, the applicant considered only pressurization of the upper reactor cavity and the refueling cavity, which is directly above the upper reactor cavity. The staff has requested the applicant to provide additional design information to support the treatment of only the upper reactor cavity.
Responsd: (April 1985)
The upper reactor cavity neutron shield (URCNS) is designed to prevent blowdown into the lower reactor cavity from a rupture of the reactor coolant piping. This justifies consideration of only upper reactor cavity subcompartment analysis.
The URCNS is a composite design of thermal insulation and neutron shielding material (borated silicone elastomer) encapsulated in a stainless steel shell. The shield is supported vertically by the neutron shield tank. Shield segments bolt together to form a unit that encompasses the reactor vessel. The shield is shown by analysis to remain intact when subjected to the postulated foadings of the pipe break (asymmetric pressurization and jet impingement) thus assuring a pressure seat between upper and lower reactor cavities.
General arrangement of the shield is shown in FSAR Figure 12.3-12.
W._______.._____..---                                                                                     .)}}