ML17202U796
| ML17202U796 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 08/20/1990 |
| From: | Partlow J Office of Nuclear Reactor Regulation |
| To: | Kovach T COMMONWEALTH EDISON CO. |
| References | |
| GL-89-16, TAC-74864, TAC-74865, NUDOCS 9008280065 | |
| Download: ML17202U796 (7) | |
Text
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. e UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 Docket Nos. 50-237 and 50-249 Mr. Thomas J. Kovach Nuclear Licensing Manager Commonwealth Edison Company - Su1te 300 Opus West I II 1400 Opus Place Downers Grove, Illinoh 60515
Dear Mr. Kovach:
Aug.ust 20, 1990
SUBJECT:
REQUESTED DELAY OF DECISION TO INSTALL HARDENED WETWELL VENT FOR DRESDEN NUCLEAR POWER STATION UNITS 2 AND 3 (TAC NOS. 74864 AND 74865)
On September 1, 1989, the NRC staff issued Generic Letter 89-16, "Installation of a Hardened Wetwell Vent," requesting that Mark I containment utilities, withiri 45 d~ys, volunteer with a schedule to install a hardened wetwell vent.
Otherwise, the Commission had directed the staff to perform plant-specific backfit analyses for facilities not elec~ing to voluntarily incorporate changes.
In your letter dated October. 30, 1989, you did not commit to
- .install a hardened vent and stated that upon co.mpletion of the Individual Plant.Examination a review of its results may.identify additional considerations specific to Dresden Units 2 and 3.
The NRC letter dated January 26, 1990, informed you that since you do not intend to install the hardened vent on a voluntary basis at this time, the*
staff would complet~ a plant~specifi~ analysis for the Dresden Units 2 and 3.
If the completed analysis lUpported the conclusion that modifications meet the requirement of the NRC backfit rule, a copy of the NRC staff analysis would be sent to you to providt:: you wi.th another opportunity to makt: the modific~tions under the provisions of 10 CFR 50.59. The NRC letter dated June 15, 1990, transmitt~d the staff's backtit analysis and the staff's conclusion based on the analysi~ that the backfit is justified for Dresden Units 2 and 3.
At your request, on July 24, 1990, you and other owners of plants with isolation condtnsi:rs who had not volunteered to install a hardened wetwell
- vent met with the NRC staff to provide additional information to support your request that the recommended improvement be evaluated as part of the Individual Plant Examination (IPE} pro~ram; and that a decision.to install the vent* be: delayed until completion of the IPE progra~.
After careful consideration of the additional supporting information provided regarding the isolation condenser plants, the staff continues to believe that Dresden Units 2*and 3 and the other similar plants should proceed without delay with the installation of the hardened wetwell vents. Our decision to proceed 1s.based, in part, on the importance of the venting sequences and their rol~ in mitigating a.1.9,.~-@.e reidiqlogical release.
Many of these sequences are 1i\\.*~* ~1*.,*,,~
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Mr. Thomas applicable to Dresden since the isolation condenser could not be assured to be operable/available for these s~quences. Examples of events leading to these sequences include stuck open SRV transients as well as the complete spectrum of primary system pipe ruptures.
Under these depressurized-conditions, the isolation-condenser is not expected to function. Therefore, venting is necessary under these conditions to maintain decay heat removal capability and minimize challenges to the containments.
Dresden Units 2 and 3 have Emergency Operating Procedures (EOPs) in place which call for venting of the containment for a wide range of plant conditions.
The venting procedures and pathway should be as reliable as possible to assure that the operators will carry out the EOP instructions. To this end, the operator should not be faced with the potential of further plant damage or possible radiological impacts on personnel when venting is a consideration.
Therefore, we view the hardening of the pathway as an important step in reducing the negative consequences of venting. Based on the above, and our discussions during the July 24, 1990 meeting, we still conclude that the results of our backfit analysis remain valid.
We believe that proceeding without delay with the installation of the hardened wetwell vent is a prudent course of action.
Accordingly, we will be initiating an Order ba~ed on the staff's backfit analysis directing you to implement the hardened vent at Dresden-Units 2 and 3~
unless we receive a commitment from you within two weeks from the date of this letter that you will voluntarily install a hardened vent capability at Dresden Units 2 and 3.
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NRC & Local PDRs PDIII-2 Rdg Plant File DCrutchfield JZwo 1 inski CMoore AThadani WRussel l BSiegel MThadani RBarrett OGC EJordan CNichols JKudrick JPa'rtlow concurrences.
Sincerely, Origina\\ signed by James G. Partlaw James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation ADR/IV/V JZwolinski*
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a Mr. Thomas to Dresden since the isolation condenser could not be assured to be
/
operable/available for these sequences.
Examples of events leading to the sequences include stuck open SRV transients as well as the complete spectr'Um of primary system pipe ruptures.
Under these depressurized conditions,,/the isolation condenser is not expected to function. Therefore, venting is necessary under these conditions to maintain decay heat removal zapa {1ity and minimize challenges to the containments.
Dresden Units 2 and 3 have Emergency Operating Procedures (EOPs) in place which call for venting of the containment for a wide range of ;Plant conditions.
The venting procedures and pathway should be as reliable as possible to assure that the operators will carry out the EOP instructions.
To this end, the operator should not be faced with the potential of furthe~ plant damage or possible radiological impacts on personnel when venting *s a consideration.
Therefore, we view the hardening of the pathway as an
- portant step in reducing the negative consequences of venting.
Based on the a ove, and our discussions during the July 24, 1990 meeting, we still conclude hat the results of our backfit analysis remain valid.
We believe that pr eeding without delay with the installation of the hardened wetwell vent is prudent course of action.
Accordingly, we will be initiating an Order ba don the staff~s backfit analysis directing you to implement the harde ed vent at Dresden Units 2 and 3, unless we receive a commitment from you with*n two weeks from the date of this letter that you will voluntarily inst l a hardened vent' capability at Dresden Units 2 and 3.
cc: See next page DISTRIBUTION Docket File NRC & Local PDRs PDII I-2 Rdg Plant File DCrutchfield JZwolfoski CMoore AThadani WRussell B iegel Thadani RBarrett OGC EJordan CNichols JKudrick JPartlow concurrences.
ames G. Partlow Associate Director for Projects Office of Nuclear Reactor Regul~tion ADR/IV/V JZwolinski*
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Mr. Thomas.
releases. Many of these sequences are applicable to Dresden since t~olation condenser could not be assured to be operable/available for these sequences.
Examples of events leading to these sequences include stuck open s.Rv transients as we.11 as the complete spectrum of primary system pipe ruptures 7*Under these depressurized conditions, the isolation condenser is not expect~ to function.
This is quite important since Dresden has Emergency Operating *rocedures (EOPs) in place which call for venting of the containment for a wid range of plant conditions.
Since venting is recognized as a significant mitigative a tion, the venting procedures and pathway should be as reliable as possibl to assure that the operators will carry out the EOP instructions. To his end, the oper~tor should not be faced with the potential of further pla damage or possible radiological impacts on personnel when venting is a onsideration. Therefore, we view the hardening of the pathway as an importan step in reducing the negative consequences of venting. Recognizing tha our recent discussions have not negated the results of our plant-specifi analysis and the importance of the implementation of the hardened vent, we b lieve that proceeding without delay with the installation of the hardened we ell vent is a prudent course of action.
Meanwhile, we are continuing to seek your c mitment to install the hardened wetwell vent based on your reconsideration of the staff's backfit analysis.
We, therefore, request that you advise us within two weeks of receipt of this letter, of your decision to commit or no to commit to the installation of the hardened wetwell vent.
cc:
See next page DISTRIBUTION Docket File NRC & Local PDRs
. PDII I-2 Rdg Plant File DCrutchfield JZwolinski CMoore AThadani James G. Partlow Associate Director for Projects Office of Nuclear Reactor Regulation BSiegel MThadani RBarrett OGC EJordan CNichols JKudrick JPartlow
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Mr. E. Since venting is recognized as a significant mitigative option, the venting procedures and pathway should be as reliable as possible to a ure that the operators will carry out the EOP instructions.
To this end, the operator should not be faced with the potential of further plant damage or ssible radiological impacts on personnel when venting is a consideration~ Therefore, we view the hardening of the pathway as an important step in re cing the negative consequences of venting. Recognizing that our recent discussions have not negated the results of our plant-specific analysis d the importance of the implementation of the hardened vent, we believe that proceeding without delay with the insta.llation of the hardened wetwell vent i a prudent course of action.
Meanwhile, we are continuing 'to seek your co1TUT1itment install the harQened wetwell vent base~ on your reconsideration of the st f's backfit analysis.
cc: See next page DISTRIBUTION Docket File NRC & Local PDRs Plant File SVarga BBoger AThadani ADromerick OGC-EJordan CNichols JKudrick Sincerely, James G. P tlow Associate irector for Projects Office o Nuclear Reactor Regulation
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Mr. Thomas August 20, 1990 applicable to Dresden since the isolation condenser could not be assured to be operable/available for these sequences.
Examples of events leading to these sequences include stuck open SRV transients as well as the complete spectrum of primary system pipe ruptures. Under these depressurized conditions, the isolation condenser is not expected to function. Therefore, venting is necessary under th~se conditions to maintain decay heat removal capability and minimize challenges to the containments.
Dresden Units 2 arid 3 have Emergency Operating Procedures (EOPs) in place which call for venting of the containment for a wide range of plant conditions.
The venting procedures and pathway should be as reliable as possible to assure that the operators will carry out the EOP instructions. To this end, the operator should not be faced with the potential of further plant damage or possible radiological impacts on personnel when venting is a consideration.
Therefore, we view the hardening of the pathway as an important step in reducing the negative consequences of venting.
Based on the above, and our discussions
. during the July 24, 1990 meeting, we still conclude that the results of our backfit analysis remain valid.
We believe that proceeding without delay with the installation of the hardened wetwell vent is a prudent cour$e of action.
Accordingly, we.will be iriitiating an Order based on the staff's backfit analysis directing you to implement the hardened vent at Dresden Units 2 and 3, unless we receive a commitment from you within two weeks from the date of this letter that you will voluntarily install a hardened veut capability at Dresden Units 2 and 3.
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J mes G. Partlow A sociate Dir~ctor for Projects Office of Nuclear Reactor Regulation
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- Mr. Thomas J. Kovach
- Conmonwealth Edison Company cc:
Michael I. Miller, E~q.
_Sidley and Austin One First National Plaza Chicago, Illinois 60690 Mr. J. Eenigenburg Plant Superintendent Dresden Nuclear Power Statton Rura 1. Route #1 Morris, Illinois 60450 U. S. Nuclear Regulatory Corrmission Re~ident Inspectors Office Dresden Station Rural Route 11
,Morris, Illinois 60450 Chafrman Board ~f Supervisors of Grundy County.
Grundy County Courthouse Morris, Illin~is 60459 Region~l Administrator*
Nuclear Regulatory-Corrmission, Region III 799 Roosevelt Road, Bldg. #4
- Glen Ellyn, Illinois 60137 I 11 inoi s Department of Nu.clear Safety Office of Nuclear Facility Safety 1035 Outer Park Drive Springfie~d. Illinois 62704 Robert Neumann Office of Public Counsel State of Illinois Center 100 W. Randolph Suite 11-300 Chicago, illfnofs 60601 Dresden Nuclear Power Statton Unit Nos. 2 and 3
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