ML17199F618
| ML17199F618 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 04/16/1975 |
| From: | US ATOMIC ENERGY COMMISSION (AEC) |
| To: | |
| Shared Package | |
| ML17199F614 | List: |
| References | |
| NUDOCS 8601290182 | |
| Download: ML17199F618 (5) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION INTRODUCTION SUPPORTING AMENDMENT NO. 6 TO LICENSE NO. DPR-19 (CHANGE NO.' 32 TO THE TECHNICAL SPECIFICATIONS)
COMMONWEALTH*EDISON COMPANY DRESDEN UNIT 2 DOCKET NO. so-2*37 By letter dated April 4, 1975, ~ommonwealth Edison Company (CE) requested a change to the Technical Specifications appended to Facility Operating License No. DPR-19 for Dresden Nuclear Power Station Unit 2.
The pro-posal would revise Section 3.5.A.7. regarding low pressure, emergency core cooling system limiting conditions of operation.
DISCUSSION Section 3.5.A. of the Technical Specifications requires that, except wider certain specified conditions, the core spray and low pressure
.coolant injection (LPCI) systems must be operable whenever irradiated fuel is in the reactor.' This section states that if the specified requirements cannot be complied with, an orderly shutdown shall be initiated and the reactor shall be in the cold shutdown condition within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Once in the cold shutdown condition~ all low pressure core and containment cooling subsystems (which includes LPCI and core spray) may* be inoperable provided-*.no work is being done which has the potential for draining the reactor vessel. The proposed change would allow the core spray and LPCI systems to remain inoper~ble when the reactor is.
- placed in the refuel mode from the cold shutdown condition provided, again, that no work is being performed which has the potential for draining the reactor vessel.
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t e-The purpose of this change is to allow CE to perform post maintenance testing of control rod drives while simultaneously performing maintenance work on the low pressure, emergency core cooling system.
The performance of these tests in the cold shutdown condition -is prevented by interlocks.
_These tests can be performed in the refuel mode.
Permitting these simultaneous functions does not result-in a decrease in the safety margin
_because performance of the control rod tests in the refueling mode does
_not inc~ease the probability of draining the reactor vessel'.
Furthermore, interlocks operable in the refuel mode prevent conditions which would cause pressurization of the reactor vessel or reactor containment.
For
- post maintenance testing of control rod drives, the LPCI and core spray perform no special safety function different from its standby function in the cold shutdown mode.
Therefore, there is no greater need for the LPCI and core spray in the refuel mode than in cold shutdown condition for the proposed operations, such as control rod testing, which do not affect the potential for draining the core. However, *since CE' s analysis does not include the entire ran.ge of activity that could be carried out in the refuel mode, the proposed technical specification will be limited to allow only post maintenance testing of control rod drives when the LPCI and core -spray systems are inop.erable.
CONCLUSION We have concluded, based on the considerations discussed above, that:
(1) because the change does not involve a significant increase in the probability or consequences of accidents pr.eviously considered and does not involve a significant decrea.Se in a safety margin, the change_
does not involve a significant hazards consideration, *(2).there is-*
reasonable assurance that the health and safety of the public will not be endangered by operatio~ in the proposed manner, and (3) such activities will be conducted in compliance with the Commission's regulations and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public.
Date: April 16, 1975
~*
-ATTACHMENT 5 EVALUATION OF SIGNIFICANT HAZARDS CONSIDERATION Description of Amendment Request The proposed ai.nendments to the Dresden Units 2 and 3 Technical Specifications include:
(1)
Various editorial, grammatical, reference changes as described in, and (2)
A change to allow post-maintenance testing of :control rod drives with the reactor in the REFUEL mode with*Low Pressure Cooling Systems inoperable (See Attachment 4).
Basis for Proposed No Significant Hazards Consideration Determination
~orranonwealth Edison has evaluated the proposed Technical Specifi-cation amendment.and' determined that it -does not represent a significant hazards consideration.
Based on the criteria for defining a significant hazards consideration established in 10 CFR 50.92(c), operation of Dresden Units 2 and 3 in-~*accordance with the proposed amendments will not:
(1) involve a significant increase in the probability or consequences of_an accident previously evaluated because:
(a)
- The miscellaneous editorial, grarranatlcal, reference changes are administrative in nature and do not allow any new operating practices or changes in equipment which could impact the probability or consequences of an a_ccident.
(b) the provision to allow control rod drive testing with Low Pressure Cooling Systems inoperable includes restrictions that the reactor be in the REFUEL mode (following achievement of cold shutdown) and specifically prohibit any simultaneous work which has the potential to drain the' reactor vessel.
The latter provision ensures _that the probability of a loss of coolant accident is not increased.by this amendment.
In addition, REFUEL mode interlocks prevent the withdrawal of more than one control rod thereby protecting against the possibility of making the reactor critical.
2 -
(2)
Create the possibility of a new or different kind of accident from any accident previously.evaluated because (a)
The administrative changes do not allow any new equipment or operating procedures which could initiate or impact the scenario of an accident or operational event, and (b) po.st maintenance testing of control rod drives is not a new activity and therefore does not introduce any new concerns regarding the initiation or progression of a transient event.
This provision does not involve any new equipment, changes to equipment, or significant changes to operating procedures and therefore cannot initiate any new events beyond those previously evaluated.
(3)
Involve a significant reduction in the margin of safety because the changes are either administrative and have no direct affect on operating limits or equipment availability or contain specific provisions to assure the margin of safety is not compromised as in the case of the control rod drive testing provision.
In consideration of the above, Commonwealth Edison has determined that the proposed amendments do not represent a significant hazards.
consideration and requests their approval under the provisions of 10 CFR 50.91(a).(4).
1152K
Nuclear Licensing Department Activities Report December 1985*
Part I:
Nuclear Reactor Regulation Highlights
- Station Activities
- Generic Activities Part II:
Inspection and Enforcement Highlights Highlights IE Bulletins and Notices IE Noncompliance summary Part III: Regulations Proposed Rules Final Rules Summary of Items Commented On Part IV:
Corning Events