ML111530445

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Exhibit 11 in Support of Pilgrim Watch Request for Hearing on a New Contention Re Inadequacy of Environmental Report, Post Fukushima
ML111530445
Person / Time
Site: Pilgrim
Issue date: 06/01/2011
From:
Pilgrim Watch
To:
Atomic Safety and Licensing Board Panel
SECY RAS
Shared Package
ML111530440 List:
References
RAS 20407, 50-293-LR, ASLBP 06-848-02-LR
Download: ML111530445 (4)
v • d • e


Text

p,10 Nov 14 05' 11 :538

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Docket No. 50-293'"

e Boston Edison Company ATTN: Ralph G. Sird Senior Vice President - Nuclear 800 Boylston Street Boston, Massachusetts 02199

SUBJECT:

HHTTAL ASSESSMENT OF PILGRIM SAFETY ENHANCEMENT PROGRAM

Dear Mr. Bird:

On July 8, 1987, Boston Edison Company (BErO) submitted a detailed description of the Pilgrim Safety Enhancement Program SEP) to the NRC. This letter transmits the staff's initial assessment of this program (Enclosure).

The staff's initial assessment has been conducted to provide an understanding of the it2 modifications and assess the safety significance of those changes, when considered singularly or along with other changes. Additionally the staff examined your evaluations of th~se changes and the aECo schedule for implementation of the modifications. Thp staff's review included a visit to BEeo offices in Braintree on July 22, 1987, conversations with r~presentativ~s of your staff over the past few weeks, and a meeting with BECo representatives in Bethesda on August 4, 1987.

The staff expects to continue its dialogue with BECo regarding the SEP program as part of its larger effort on severe accidents. The generic issue of containment venting has been under consideration by BWR owners and the ~IRC for several years. It is a complex issue fraught with con1licting safety objectives. Because the severe accident effort is ongoing, the staff ;s not prepared to endorse the use of the Direct Torus Vent System (Drvs) at this time.

To assist the staff in Its consideration of the DTVS, we request you provide the

~ staff your written response to the questions contained in the enclosure .

  • the need for Technical Specifications on a containment Isolation valve.

The staff still has questions regarding the proposed modification to the reactor core isolation cooling (~~JC) system. Prior to Implementing this modification the staff requests at BECo conduct an assessment of hydrodynamic loads on the ReIC piping and supports, based on the proposed exhaust pressure of 46 psig, and make the results of that assessment available to the staff.

The staff reque~ts clarification regarding the function of one valve in the backup nitrogen supply system. As described in the enclosure, v~lve AO-4356 appears to be a containment 1so1ation valve and, consequ~ntly, would be appropriate for inclusion in the Technical Specifications.

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p.11 Nov 14 0511:54a August 2[, 1~87 The 5taff request. a rificatlon regar:::g the mo. : .* iOI: to the RHR system to provide additional sources of water for RPV 1nj~*.:;n and containment spray. This modification may require a change to 'Technical Specifications.

As described 1n the enclosure. the valves to be ar .J to the RHR system become part of the reactor coolant pressure boundary dur J operation of the RHR system and, consequently, are subject to surveillance tF .ing.

We commend your efforts and leadership on this Jgram. The Quality of your July 8, 1987 submittal ;s impressive and the c .leratfon of your staff ;s appreci ated.

As you are aware, the NRC will continue its spection of SEP m6~ifications, review of affected ~lant procedures, and o~ rvutic~ of related onsite activities. We will keep you informed. s* .Id we have additional concerns about this program. Please contact the' . Pl"o.iect Manager if you 'have any Questions.

Sincerely.

/5/

Steven A. Varga, Director Division of Reactor Projects 1/11 Office of Nuclear Reactor Regulation Encl OSllre:

As stated cc w/enclosure See next page DISTRIBUTION:

POl-3 R/F PDR C. Tinkler T. Collins N. Su V. Thomas O. Chopra B. Cl ayton J. Wiggins, R: r S. Col11ns, R: 1 W. Russell, R: I M. McBride. R: I

~See previous concurrence

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Nov 14 05 11:54a p.12

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Enclosure INITIAL ASSESSMENT OF PILGR If" SAFC"T'r ,ANCEMENT PROGRAM Note: Section numbers refer to sect~on nu~' ,

  • in the SECo submittal of July 8, 1987.
1. Sect. 3.2
  • Installation of Direct .orus Vent System (OTVS)

The proposed desl~n modiffcatio~ ssociated with the direct...... torus vent system (DTVS) ~rovldes a dlrec' lent path from the torus air SPace to the main stack, 1n parallel with .d bypassing the Standby Gas Treatment System (SGTS). The OTVS provides new 8" line branching off thE e~'isting torus purge exhaust line betwee' ;he containment ~solatlon valves (outside containment) with a recCl~""'!ctfon to the existing torus purge exhaust line downstream of the SGTS. T~e new torus vent line is also provided with its own containment ir.lation valve and a rupture disc, set to relieve at 30 pstg .

The installation' an additional branch line and containment s .....\... h, I'> "Cc "'1 V'>,

isolation valve lOuld require a change to the plant Technical l... * (" ...........

Spec~ffcations. Therefore, it is our view that installation of the OTVS ..... ,'" . ~"",J.

~ cannot be implemented under the provisions of 10 CFR 30.59.

To assist the staff in its consideration of the proposed DTVS, we re~uest a written response to the following concerns:

1) Prov~de comprehensive analyses of accident sequences, with their estimated frequency of occurrence, for which the vent would be ca11ed upon to operate.
2) Provide estimate of the fraction of those sequences where the vent would be operated but where the accident would have been terminated short of containment failure without vent operation. Consider the following situations in the accident sequences:
  • (a)

(b) electric power returned to service equ~pment returned to service (e) m1s-d~agnosed situation corrected by operators

p.13 Nov 14 0511 :54a

./

3) Provide comprehensive analysis of t'~SJ accident sequences that:

(a) could be improved by correct .se of the vent. or (b) could be initiated or made Jrse by incorrect operation of the

. vent *

4) Provide analysts of seQuen r thut could lead to containment failure by operation of the vent Ilowed by excessive pressure differential (buck 11 ng).
5) Provide analysis of.e probabil ity of vent failure wr.en called upon.
6) Provide analysis of maintenance or surveillance errors on the vent system that could induce accidents.
7) Provide an estimate of the radioactivity released for all sequences when the vent could be opened, including botr. correct usage according to procedures and incorrect usage due to human error or equipment malfunction.
2. Sect. 3.3 - Containment Spray Header Nozzles The objective Of installing new containment spray header nozzles in the drywell is to improve the performance of drywell spray under severe accident conditions and to provfde greater flexibility of use of the sprays under a variety of accident conditions. The replacement spray nozzles are identical to the existing nozz1es except that the rePlacement) nozzle assembly has 6 out of 7 nozzle outlets capped while the original
  • nozzle assemblies had all 7 nozzle outlets open. The effect of capping nozzles is to reduce drywell spray flow when the spray water is provided by the RHR pumps (5000 gpmJ and preserve a basic spray pattern when the spray
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