ML20058A589
| ML20058A589 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 10/22/1990 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20058A587 | List: |
| References | |
| GL-88-10, NUDOCS 9010290029 | |
| Download: ML20058A589 (3) | |
Text
_
'J.
e,'*
p asa
+f k
UNITED STATES
- y-g-
NUCLEAR REGULATORY COMMISSION 7,'
-l WASHING TON, D. C. 20555 k.
/
5...*,
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION g
L EVALUATION OF PHILADELPHIA ELECTRIC COMPANY'S RESPONSE TO NRC REVIEW L
SUBMITTALS RESPONDING TO NRC GENERIC LETTER 88
- PHILADELPHIA ELECTRIC COMPANY LIMERICK GENERATING STATION, UNITS 1 Aho 2 DOCKET N05. 50-352 AND 50-353-
1.0 INTRODUCTION
By letter dated June 8,-1990, philadelphia Electric Company (the 1
licensee)submitteditsresponsetoNRCSafetyEvaluation(SE)
"- EVALUATION 0F NRC GENERIC LETTER 88-01 RESPONSE" dated March 6, 1990.
Supplemental information was provided by the. licensee during a telephone
.. conference call on September 12, 1990.. The NRC in its letter dated March
_6,.1990(GL)88-1 responses;datedAugust2,1988, April 28,1989, provided the results of NRC's review of the licensee's Generic Letter o
May 30, 1989; and September 11, 1989.
The NRC'had found the licensee's L'
GL-88-01Lresponses to the five specific items and 131 staff positions presented in GL-88-01 acceptable with some exceptions. The GL-88-01 exceptions identified by.the NRC.SE dated March 6, 1990 were addressed by the licensee in its June 8, 1990L1etter.
l l'
l 2.0 DISCUSSION L
The licensee's? response dated June 8, 1990, to NRC'1etter dated March 6, 1990,
=was reviewed by the staff. The: licensee.also provided additional information as to examplesiof material types used-in LGS' Unit Itand 2, by phone call on-September 12,;1990. The-licensee's response dated March 6,.1990, and additiona1'information f.er subject phone: call was found to be acceptabic with Lthe exception of the-licensee's inspection plan for the Reactor Water Cleanup System welds 'beyond the outer containmen+ isolation valves in LGS,. Unit 1.
Theistaff's' review-of the' licensee's IGSCC inspection planc:found that the W
majority-of the welds in.both LGS, Unit 1 and 2 were classified as IGSCC L,,<
1 Category "A" welds ~. For, IGSCC Cateogry "A" welds GL-88-01 regi: ires
- inspection of 25L of the Category "A" weld ppulation every 10 years and at.
least 12%;in 6 years.
Examples of materials being;used at LGS, Units 11and.2:
L'
are Type' ASTM 316K (Reactor Recirculation), and 316L' (RHR). 'In addition, the -
licensee proposed to amend the LGS : Unit ? and 2 TSs in accordance with m
~ GL-88-01 with regard te a statement on ISI,: include-limiting the increase in-leakage to 2!gpa over e 24' hour period,; and t: the staff's position that 11eakage may te measured every e195t:hoeirs instead of every 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.as' required -
~
t
- by GL-88 @l.-
furthermore, the licensee-intends to follow the staff positions--
3 l
on weld overlays, and clamping devices, and stress improvement if situtions i
9010290029 90io22 PDR ADOCK 03000352 P
,r t
,, dictate the use of these techniques at LGS.
The licensee will also approach the NRC on a case-by-case basis if deviations from the staff positions are t
deemed necessary.
The -licensee's inspection plan for the RWCU System welds outboard of the containment isolation valves in LGS, Unit I was found to be unacceptable. The RWCU system generally has the most aggressive environment with regard to IGSCC t
and should be inspected.
Although, the subject piping is not required to be examined in accordance with the ASME Section XI, ISI Program, GL-88-01 applies to all BWF piping made of austenitic stainless steel that is four inches or g
1arger in nominal diameter and contains reactor enolant at a temperature above
.200 degrees F during power operation, regardless of Code classification.
The staff is aware of.the licensee's concerns with regard to the high levels of worker radiation exposure during the preparation and examination of the subjectwelds. THe_ staff has also considered that LGS, Unit 1 has been operational for a relatively short period of time. Therefore, during each refueling outage for the First Ten Year ISI Period, the licensee should
. inspect at least 5% of LGS, Unit 1 RWCU weld population (195 welds) that are
-outboard of the containment isolation valves.
The inspection of the subject LGS' Unit 1 RWCU weld sample should begin with the scheduled refueling outage, 3following the third refueling outage (September 1990).
The-1icensee has. replaced the LGS, Unit 2 RWCU piping beyond the outer containment isolation valves with ASTM 316NG grade material and per GL-88-01 this material (316NG) is considered to be resistant to sensitization and IGSCC in BWR_ piping. The subject. piping is included in_the.151' Pressure Testing Program and the system is pressure tested and visually examined in accordance
- with the aaplicable rules of the ASME Code,Section XI, each inspection period. Thus, the inspection plan proposed by-the licensee for LGS, Unit 2 RWCU welds beyond the outer containment isolation valves is acceptable.
l
3.0 CONCLUSION
- Based on the review of-the licensee's respons'e dated June 8, 1990 and
' additional information provided by'a' phone call on~ September 12, 1990, with regard'to NRC'1etter dated March 6, 1990, the staff finds the licensee's response acceptable with..the exception'of the inspection plan for-the LGS,
~'
Unitil RWCU System welds; outboard of the outer containment ~ isolation valve.
- Beginning with the scheduled refueling outage, subsequent'to the third; refueling! outage;(September 1990) and.during'each refueling' outage for the
. First Ten Year ISI Period, the~1icensee should inspect at least 5% of the
- subject-(195 welds)1 LGS, Unit 11 RWCU weld population.
Furthermore, for subsequent Ten Year ISI Periods the licensee should increase the inspection?
sample to'10% of; the subject.(195 welds) LGS, Unit 1 RWCU_ weld population.
}
i 1
i
~.
- e-
<.o....
. -r The staff also concludes that the proposed response provided in the licensee's
- 4 ',
letter dated June 8, 1990, and additional information provided by phone on 65 September 12, 1990, and implementation of the staff's recommendation above to inspect the LGS, Unit 1 RWCU welds will provide reasonable assurance of maintaining the long-term structural integrity of austenitic stainless steel piping at the Limerick Generating Station, Units 1 and 2.
Principal Contributors:
T. McLellan W. Koo 1
l l
1 i
h i
l
+
k I
i Iii: ;7 ',
i
.