ML020870135
| ML020870135 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/05/2002 |
| From: | Richard Ennis NRC/NRR/DLPM/LPD1 |
| To: | Clifford J NRC/NRR/DLPM/LPD1 |
| Ennis R, NRR/DLPM, 415-1420 | |
| References | |
| TAC MB4555 | |
| Download: ML020870135 (4) | |
Text
April 5, 2002 MEMORANDUM TO: James W. Clifford, Chief, Section 2 Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation FROM:
Richard B. Ennis, Sr. Project Manager, Section 2 /RA/
Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation
SUBJECT:
DOCUMENTATION OF CONFERENCE CALLS REGARDING REACTOR VESSEL HEAD INSPECTION ACTIVITIES FOR MILLSTONE NUCLEAR POWER STATION, UNIT NO. 2 (TAC NO. MB4555)
On March 13, 2002, the Nuclear Regulatory Commission (NRC) staff had a conference call with Dominion Nuclear Connecticut, Inc. (the licensee) to discuss the implications of the Davis-Besse findings related to NRC Bulletin 2002-01, with respect to the ongoing refueling outage for Millstone Nuclear Power Station, Unit No. 2 (MP2). The licensee developed three action items based on the Davis-Besse findings. The three action items were: (1) inspect the insulation package on top of the reactor vessel head, (2) conduct ultrasonic scans of the reactor vessel head, and (3) evaluate the applicability of the Davis-Besse radiation monitor fouling problems as they relate to MP2.
On March 21, 2002, the NRC staff had another conference call with the licensee to discuss the results of the three action items. The following provides a brief discussion of the licensees response to each of the action items.
1)
Inspect the insulation package on top of the reactor vessel head: Because of the construction and application of the insulation package to the reactor vessel head, the licensee was unable to inspect underneath the insulation. However, there was no evidence of severe buildup of boric acid on the insulation. In one area of the insulation the licensee noted staining, but ultrasonic measurements in the area underneath the staining indicated full reactor vessel head thickness.
2)
Conduct ultrasonic (UT) scans of the reactor vessel head: The licensee had performed a 100% UT inspection of its control element drive mechanisms (CEDMs). It identified no through-wall defects (several part through-wall defects were identified). Based on the Davis -Besse findings, the UT data was re-reviewed and no degradation similar to Davis-Besse was identified. In addition, the licensee performed ultrasonic scanning measurements at various locations around the head in areas where boric acid deposits were suspected or confirmed. These measurements did not identify any degradation (i.e., the thickness of the head was as expected).
J. Clifford 3)
Evaluate the applicability of the Davis-Besse radiation monitor fouling problems as they relate to MP2: The licensee reviewed its radiation monitor history and determined that MP2 does not have a history of boron or iron plugging of radiation monitor filters.
In conclusion, the licensee stated that they did not have any indications on the reactor vessel head similar to those which were identified at Davis-Besse.
Based on the preliminary findings from Davis-Besse, the inspections performed by the licensee, and the susceptibility of MP2 to nozzle cracking, the NRC staff did not identify any issues that needed additional follow-up prior to plant restart. The staff will document its formal review after receiving the licenseesBulletin 2002-01 response.
Docket No. 50-336
- See previous concurrence OFFICE PDI-2/PM PDI-2/PM*
PDI-2/LA PDI-2/LA EMCB/PM*
PDI-2/SC NAME REnnis DStarkey TClark MOBrien (changes only)
SBloom JClifford DATE 04/05/02 04/02/02 04/02/02 04/05/02 04/04/02 04/05/02