ML20058B301
| ML20058B301 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 10/17/1990 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20058B296 | List: |
| References | |
| NUDOCS 9010300085 | |
| Download: ML20058B301 (3) | |
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 39 TO FACILITY OPERATING LICENSE NO. NPF.37, AMENDMENT NO. 39 TO FACILITY OPERATING LICENSE NO. NPF 66, AMENDMENT NO. 26 TO FACILITY OPERATING LICENSE NO. NPF-72, A,ND AMENDMENT NO. 26 TO FACILITY OPERATING LICENSE NO. NPF-77 COMMONWEALTH EDISON COMPANY BYRON STATION, UNIT NOS. 1 AND 2 BRAIDWOOD STATION, UNIT NOS. 1 AND 2 DOCKET N05. STN 50-454, STN 50-455, STN 50-456 AND STN 50-457
1.0 INTRODUCTION
By letters dated April 20, 1990 and September 6, 1990, Commonwealth Edison Company (CECO) (the licensee) proposed an amendment to the Technical Specifi-cations for both Byron Station Unit Nos. I and 2 and Braidwood Station Unit Nos. I and 2.
The proposed amendment revises TS 3/4,6.3, Containment isolation Valves, to delete the requirement for Type C leakage rate testing for specific Steam Generator (SG) blowdown isolation valves (while continuing to leakage rate test under the Inservice Testing (IST) program) and to add a requirement for Type C leakge rate testing of the 1/2 SI 8968 safety injection valves.
The staff's review of the licensee's proposal and of the licensee's bases for the proposed changes is given below.
2.0 EVALUATION The steam generator (SG) Blowdown lines transfer secondary water to the SG blowdownsystem(SD)forcleanupduringplantoperation. The SG blowdown lines (and the attached secondary side of the SG and main steam system) are neither a part of the reactor coolant system (RCS) pressure boundary nor do they open directly to the containment atmosphere under post-LOCA conditions.
i InaccordancewithGeneralDesignCriterion(GDC)57,thesteamgenerator shell and the lines attached to it (such as the main steam line feedwater line,andtheSGblowdownlines)constituteaclosedsysteminsIde containment, and it is one of the containment isolation barriers for each associated containment penetration. The swcond redundant barrier at each l
penetration is a valve, such as the main steam or main feedwater isolation valves and the SG blowdown valves.
However, the main steam and main feedwater isolation valves are not required to be locally leakage rate l
9010300085 901017 DR ADOCK 05000454 p
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2 tested (Tyre C tested) in accordance with Section 11.H.4 of Appendix J to 10 CFR part 50, it should be noted that the integrity of the closed systems inside centainment are tested during periodic Type A (integrated leakage rate) tr. sting. By letter dated September 6, 1990, the licensee described its cc.nmitment to leakage rate test the subject valves as part of the IST proi, ram, using water or air as the test medium in accordance with ASME Section XI.
The staff considers leakage rate testing of these valves to be a necessary part of periodic verification of the valves' capability to fulfill their safety function.
Therefore, the testing committed to by the licensee is acceptable.
The staff has previously allowed other plants to discontinue Type C testing of the SG blowdown valves (for example, Comanche Peak and Seabrook) on the following basis:
the secondary system is a closed system inside containment and is not postulated to rupture during en accident.
It will preclude the containment atmosphere from reaching the associated isolation valves; therefore, the valves will not be relied on to limit containment leakage, in light of the above discussion and the licensee's commitment to leakage rate testing of the SG blowdown valves under the IST program, the staff finds the licensee's proposal to discontinue Type C testing of the SG blowdown valves acceptable.
It should be noted that the integrity of the closed systems inside containment will be tested during periodic Type A (integrated leakage rate) testing.
Therefore, the staff finds the licensee's proposal to discontinue Type C testing of the SG blowdown valves acceptable.
However, this does not necessarily relieve the SG blowdown valves from the testing requirements of the Inservice Testing (IST) program under ASME Section XI and 10 CFR 50.55a.
The licensee's submittal stated that the valves perform other safety functions besides limiting containment leakage, such as conserving SG secondary side water mass for heat sink during an accident. These safety functions should be contidered when i
I determining testing provisions under the IST program and whether the testing should include leakage rate testing.
However, the IST program is outside the scope of this review, which only addresses Appendix J requirements.
The second requp, for addition of a requirement that would mandate Type C leakage rate tesung for the 1/2 S18968 safety injection valves is i
conservative and is therefore acceptable to the staff.
1
3.0 ENVIRONMENTAL CONSIDERATION
1 These amendments involve a change to a requirement with respect to the instal-lation or use of the facility components located within the restricted areas as defined in 10 CFR 20 or a change to a surveillance requirement. The staff has determined that these amendments involve no significant increase in the amounts, and no significant change in the types of any effluents that may bereleasedoffsiteandthatthereisnosignifIcantincreaseinindividual or cumulative occupational radiation exposure.
The Commission has previously issued a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding.
3 Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuantto10CFR51.22(b)no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
4.0 CONCLUSION
Since the SG blowdown valves will not be relied upon to perform a containment isolation function, the staff finds the licensee's proposal to discontinue the Type C testing on SG blowdown valves currently required by TS 3/4.6.3 to be acceptable.
Further, the staff finds that the addition of a requirement to Type C test the 1/2 51 8968 safety injection valves is also acceptable.
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public willnotbeendangeredbyoperationintheproposedmanner,(2)such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the puolic.
Principal Contributors:
J. pulsipher Dated:
October 17, 1990 i