ML19340A628
| ML19340A628 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 02/28/1977 |
| From: | Bolger R COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML19340A625 | List: |
| References | |
| NUDOCS 8009020576 | |
| Download: ML19340A628 (7) | |
Text
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Ons First f47tiorni Plata. CNeago. Ithnois Accress Reply to: Post Othce Box 767 Chicago, Illirtois 60690 February 28, 1977 l
Mr. James G. Keppler, Director Directorate of Inspection and Enforcement - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Dresden Station Units 1, 2, and 3 Response to IE Inspection Report l
Nos. 50-10/76-27, 50-237/76-28, and 50-249/76 NRC Docket Nos.
50-10, 50-237, and 50-249 Reference (a) :
J. G. Keppler (NRC) Letter to Byron Lee (CECO) dated February 3, 1977.
Dear Mr. Keppler:
Attached is the response to the items listed under
" Infractions" in the enclosure to Reference (a).
As described in Reference (a), Item B required no response.
Neither this response nor the original report contain proprietary information.
Please address any additional questions on this matter to this office.
Very truly yours, f)
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Bol er Assistant Vice President Attachment 80090205f(
!!.AR 21977
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INFRACTION A:
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. Lack of a program to calibrate instruments which verify that safety related systems perform within Technical k_s Specification requirements.
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Discussion:
This infraction addresses the calibration of instruments associa'.ed with safety related systems and various required parameters of those systems which are required in the Technical Specifications. The Technical Sr acifications lists specific instruments which must be calibrated and also states the required calibration frequency. All of these instruments are presently on the master surveillance list.
The instruments of concern in this infraction are those instruments which are not specifically mentioned in the Technical Specifications, but which are utilized to verify Technical Specification Limits.
In the past, calibration of these instruments has been on an "as needed" basis.
Corrective Action and Corrective Action to Avoid Recurrence:
The corrective action for this infraction will be to review the Technical Specifications for the three Dresden Units and identify all required limits that are monitored by instruments which are not now on a surveillance program.
These instruments
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will then be assigned a calibration frequency and placed on a surveillance program.
Date of Full Compliance:
The surveillance list for Dresden 2 and 3 will be completed by September 30, 1977. The Dresden Unit 1 surveillance progrr.m sill be implemented as soon as practicable af ter all pending major instrumentation modifications are completed.
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INFRACTION B:
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Unit 2 moisture separator room high radiation door, c
-Discussion:
No response required per item 5.C c f Report Details, page 7 of I.E. Report.
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INFRACTION C:
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Flood door to Unit 3 LPCI/ Core Spray Area.
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Discussion:
Contrary to Technical Specification 3.7.C.2,'a flood door to one of the two LPCI and Core Spray Compartments was found open and unattended during power operation of Unit 3.
The occurrence was discovered by the Region 3 Compliance Inspector during his routine plant inspection tour. -1Rua door was immediately closed upon discovery.
Corrective Action:
The door was closed by personnel returning to work in the area.
The door had been lef t open prior to their leaving earlier in the day following cleanup activities in the compart-
, ment and adjoining torus area. The crew was reminded of the importance of maintaining these doors closed while not in attendance.
s Corrective Action to Avoid Recurrence:
Warnings are presently painted 5n the doors to " Keep This Door Closed". Since the design of the flood door is currently awaiting change, it is believed that no additional warning measures are appropriate in tha immediate future.
At the present time, these doors are verified closed once per week as required by 'aection 4.7.C.2 of the Technical Specifications. To provide greater assurance that these doors are closed, a daily door closed verification will be made.
4 Date of Full Comnliance:
Technical Specification requirements were fully satisfied immediately after the occurrence was identified.
The followup procedural verification of door closure on a daily basis will be in effect by March 1, 1977.
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INFRACTION D:
Identification of CRD's F-5 and J-11 being temporarily uncoupled.
Discussion:
During 50% scram testing on D'ecember 13, 1976, CRD F-5 was scram tested and withdrawn to position 48.
At this time, the drive was found to be uncoupled. An insertion to position 44 and subsequent withdrawal to position 48 indicated the drive to be recoupled. A second scram and withdrawal to position 48 again uncoupled the drive.
CRD F-5 was then inserted to position 00 and disarmed.
During a routine startup on December 28, 1976, CRD J-11 was found to uncouple and over travel when withdrawn to position 48.
An insertion to position 46 and subsequent withdrawal to position 48 in,dicated the drive to be recoupled. Additional testing was conducted to verify that the drive was coupled.
CRD uncoupling has occurred at Dresden several times in the past.
Disassembly and inspection of these drives has revealed an unlatched inner filter assembly as the mode of failure. A detailed review of the synptoms associated with the uncoupling of CRD's F-5 and.J-ll concluded that the mode of failure was again an unlatched inner filter. The nature of this uncoupling mechanism is such that control rod insertion will result in CRD recoupling and that uncoupling can only occur when a CRD is at position 48.
Therefore, if the drives can be verified to be coupled at position 48, moving them into the core and repositioning thereaf ter can occur without the concern of an inadvertent uncoupling.
Corre tive Action:
An operating order was issued stating
- 1) Whenever F-5 or,J-11 is withdrawn to position 48, they will be checked for overtravel.
- 2) Whenever F-5 or J-ll is exercised or withdrawn to positions other than 48, control blade following will be conducted using LPRM detectors.
3)
If any additional uncoupling events occur, all CRDs (including F-5 and J-11) which have exhibited uncoupling will be fully inserted and disarmed per Section 3.3.B.1 of the Technical Specifications.
Dresden Station has a change to Section 3.3.3 of the Technical Specifications under NRC review.
This change will allow CRD recoupling under specified conditions.
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INFRACTION D (Continued):
i Corrective Action to Avoid Recurrence
. The Station believes that the issuance of the above mentioned operating order, the pursuit of the above mentioned Technical Specification change and the replacement of F-5 and J-11 with rebuilt CRDs prior to the end of the next Unit 2 refueling outage will be sufficient to preclude recurrence.
Date of Full Compliance:
Full compliance has been achieved since t.he rods are currently coupled.
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' INFRACTION E:
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The reporting of the temporary uncoupling of CRD's F-5 and J-11 on 30 day basis rather than a 14 day basis as required by Section 6.6.B.1 of the Technical Specifications.
Discussion:
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This infraction involves the CRD's discussed under Infraction D.
At the time the temporary CRD uncoupling was reported, CRD's F-5 and J-ll were recoupled. As explained under Infraction D, the nature of this uncoupling mechanism is such that recoupling cannot be avoided when a CRD is inserted.
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the CRD's had experienced uncoupling earlier, but were not uncoupled when reported, the station believed that reporting under a degraded mode of operation would be appropriate.
Corrective Action, Corrective Action to Avoid Recurrence, and Date of Full Compliance:
Future reporting will be in accordance with the Technical Specificaticas.
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