L-01-002, NRC Bulletin 2001-01: Circumferential Cracking of Reactor Pressure Vessel Head Penetration Nozzles - Updated Response

NRC Bulletin 2001-01: Circumferential Cracking of Reactor Pressure Vessel Head Penetration Nozzles - Updated Response

ML023030471
Person / Time
Site:	Palisades
Issue date:	10/22/2002
From:	Cooper D Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-01-002, BL-02-002
Download: ML023030471 (5)

Text

r Committed to NuclearExcelence. Operated by NuclearPalisades Nuclear Management Plant Company, LLC October 22, 2002 U.S. Nuclear Regulatory Commission 10 CFR 50.54(f)

ATTN: Document Control Desk Washington, DC 20555-0001 DOCKET 50-255 - LICENSE DPR PALISADES NUCLEAR PLANT NRC BULLETIN 2001-01: CIRCUMFERENTIAL CRACKING OF REACTOR PRESSURE VESSEL HEAD PENETRATION NOZZLES - UPDATED RESPONSE On March 29, 2002, Nuclear Management Company (NMC), LLC provided an updated response to the Nuclear Regulatory Commission (NRC) Bulletin (BL) 2001-01, "Circumferential Cracking of Reactor Vessel Head Penetration Nozzles." On August 9, 2002, the NRC transmitted BL 2002-02, "Reactor Pressure Vessel Head and Vessel Head Penetration Nozzle Inspection Programs." While preparing the response to BL 2002-02, an error was discovered in the updated response to BL 2001-01.

A calculation of the effective degradation years (EDY) value was performed as part of the response to BL 2002-02. While developing the EDY calculation, NMC discovered that the equivalent effective full power years (EFPY) value of 22.5 previously reported in the updated response to BL 2001-01 was incorrect. The correct EFPY value is 23.9 years of additional operation from March 1, 2001, until reaching the same time at temperature that the Oconee Nuclear Station Unit 3 had at the time that its leaking nozzles were discovered in February 2001. There is no re-categorizing of susceptibility groups with this change.

Palisades remains in the five to thirty year susceptibility group.

NMC is providing an updated response to items l.a and the reference section. The attachments to the original response remain unchanged and are not included.

SUMMARY

OF COMMITMENTS This letter contains no new commitments and no revisions to existing commitments.

I declare under penalty of perjury that the foregoing is true and accurate. Executed on Octo er 22, 2002.

Doug sE. Coper Site Vice-President, Palisades CC Regional Administrator, USNRC, Region III Project Manager, USNRC, NRR A)*

EnclosureNRC Resident Inspector - Palisades * *~

27780 Blue Star Memorial Highway 0 Covert, Ml 49043 Telephone: 616.764.2000

ENCLOSURE NUCLEAR MANAGEMENT COMPANY, LLC PALISADES NUCLEAR PLANT DOCKET 50-255 OCTOBER 22,2002 NRC BULLETIN 2001-01: PALISADES PLANT UPDATED RESPONSE Three Pages Follow

NRC BULLETIN 2001-01: CIRCUMFERENTIAL CRACKING OF REACTOR VESSEL HEAD PENETRATION NOZZLES PALISADES PLANT UPDATED RESPONSE

1. Requested Background and Descriptive Information

a. Plant Specific PWSCC Susceptibility Ranking primary Palisades Nuclear Plant was originally ranked for the potential for vessel water stress corrosion cracking (PWSCC) of the reactor pressure model and plant (RPV) top head nozzles using the time-at-temperature specific input data reported in MRP-48 [1]. Nuclear Management Company in 2002.

(NMC), LLC re-evaluated the Palisades reactor head temperature the five to The re-evaluation results in Palisades being re-categorized into (EFPYs) of thirty year susceptibility group, with 23.9 effective full power years the same time at additional operation from March 1, 2001, until reaching time that temperature that Oconee Nuclear Station Unit 3 (ONS3) had at the its leaking nozzles were discovered in February 2001 [2].

Using the criteria stated in Nuclear Regulatory Commission (NRC) Bulletin 2001-01, Palisades Nuclear Plant falls into the NRC category of plants top head considered to have a moderate susceptibility to PWSCC of the RPV nozzles.

b. Description of Vessel Head Penetration (VHP) Nozzles CRDM Palisades Nuclear Plant has 54 total RPV head nozzles including 45 The vent nozzles, 8 incore instrument (ICI) nozzles, and one vent nozzle.

nozzle is located near the center of the reactor head, at a center-to-center and vent distance of 11.98 inches from the nearest CRDM. The CRDM, ICI nozzles are made of SB-1 67 Alloy 600. Additional requested nozzle information is provided in Table 2-3 of MRP-48 [1].

c. Description of Reactor Pressure Vessel (RPV) Head Insulation As reported in Table 2-1 of MRP-48 [1], Palisades Nuclear Plant has blanket contoured RPV head insulation.

Two layers of blanket insulation strips rest upon the reactor head at right angles to each other, beneath a stainless steel cover assembly. The hinged, latched covers are removable. The blankets can be removed and re area installed or replaced. An attached photograph depicts the reactor head with some covers removed. (Attachment 1)

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NRC BULLETIN 2001-01: CIRCUMFERENTIAL CRACKING OF REACTOR VESSEL HEAD PENETRATION NOZZLES PALISADES PLANT UPDATED RESPONSE Years

d. Description of RPV Head and Nozzle Inspections Within Past Four As reported in Table 2-1 of MRP-48 [1], Palisades Nuclear Plant has the performed visual inspections of the reactor top head area for leaks per current Generic Letter 88-05 leakage detection program, but no additional four RPV head and nozzle inspections have been conducted within the past years (as of August 31, 2001).

of the

e. Description of the Configuration of Equipment and Cables on Top Reactor Pressure Vessel Head A description of the configuration of equipment and cables on the vessel head is attached to this response. (Attachment 2)

2. Previously Experienced Leakage From or Cracking in VHP Nozzles nozzles.

Palisades Nuclear Plant has not experienced leakage or cracking in VHP No further response to this question is required.

of ONS3

3. Plans for Future Inspections - If Susceptibility Ranking Is Within 5 EFPY of ONS3.

The susceptibility ranking for Palisades Nuclear Plant is not within 5 EFPY No further response to this question is required.

5 EFPY and

4. Plans for Future Inspections - If Susceptibility Ranking Is Greater Than Less Than 30 EFPY of ONS3 upper NMC will perform a 100% effective visual examination of the reactor head be to metal surface during the next refueling outage. Qualification requirements will Pressure the 1989 Edition of American Society of Mechanical Engineers Boiler and leakage from the Vessel Code,Section XI. The acceptance criterion will be zero reactor head and penetration nozzles.

in The bases for concluding that regulatory requirements are met are discussed MRP-48 [1].

If leakage is detected, it will be investigated and repaired as needed, in accordance with the current NMC repair/replacement program at Palisades including applicable and codes and standards. Any indication of leakage or cracks will be evaluated characterized using a combination of surface and/or volumetric examinations.

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NRC BULLETIN 2001-01: CIRCUMFERENTIAL CRACKING OF REACTOR VESSEL HEAD PENETRATION NOZZLES PALISADES PLANT UPDATED RESPONSE

5. Reporting of Future Inspection Results Palisades Nuclear Plant will provide the information requested in Item 5 of NRC Bulletin 2001-01, or indicate that no leakage was identified, within 30 days after plant restart following the next refueling outage.

During the next refueling outage, NMC will perform a 100% effective visual examination of the Palisades reactor vessel head upper metal surface in accordance with BL 2001-01.

References

1. PWR MaterialsReliability ProgramResponse to NRC Bulletin 2001-01 (MRP-48), EPRI, Palo Alto, CA: 2001. TP-1006284.

2. EA-C-PAL-01 -03348-01, Rev. 2, "Upper Head Fluid Temperature for Palisades Reactor (Westinghouse Calculation CN-WFE-02-5, Rev.0)"

Attachments Attachment 1, Photograph of Palisades Reactor Vessel Head Insulation Attachment 2, Configuration of Equipment and Cables on the RPV Head Page 3