[Federal Register Volume 61, Number 72 (Friday, April 12, 1996)]
[Notices]
[Pages 16270-16272]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-9145]



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NUCLEAR REGULATORY COMMISSION


Commonwealth Edison Company (LaSalle County Station, Unit Nos. 1 
and 2)

[Docket Nos. 50-373, 50-374]

Exemption

I

    The Commonwealth Edison Company (ComEd, the licensee), is the 
holder of Facility Operating License Nos. NPF-11 and NPF-18, which 
authorize operation of the LaSalle County Station, Units 1 and 2 (the 
facilities). The licenses provide, among other things, that the 
facilities are subject to all rules, regulations, and orders of the 
Nuclear Regulatory Commission (the Commission) now or hereafter in 
effect.
    The facilities consist of two boiling water reactors located at the 
licensee's site in LaSalle County, Illinois.

II

    Section 50.54(o) of 10 CFR Part 50 requires that primary reactor 
containments for water-cooled power reactors meet the leakage rate test 
requirements in either Option A or B of Appendix J, to 10 CFR Part 50. 
Appendix J, Option B, ``Primary Reactor Containment Leakage Testing for 
Water-Cooled Power Reactors,'' contains performance-based requirements, 
schedules, and acceptance criteria for tests of the leak tight 
integrity of the primary reactor containment and the systems and 
components which penetrate the primary containment. The Commission, in 
its letter dated March 11, 1996, authorized the licensee to adopt 
Option B of Appendix J for the LaSalle Station. Section III.B of 
Appendix J, Option B, requires, in part, that leak rate testing must 
demonstrate that the sum of the leakage rates at accident pressure 
(Pa) of Type B tests, and pathway leakage rates from Type C tests, 
is less than the performance criterion (i.e., La) with margin, as 
specified in a plant's Technical Specifications (TSs).
    The version of Appendix J in effect at the operating license review 
stage for the LaSalle Station is now identified as Option A of Appendix 
J. Both Options A and B of this appendix implicitly require that the 
measured leakage past the inboard and outboard main steamline isolation 
valves (MSIVs) be included in the evaluation of the Type B and C tests. 
This combination of measured leakages is identified as the combined 
local leak rate test results.
    When LaSalle was originally licensed, ComEd requested an exemption 
from

[[Page 16271]]

this requirement which the staff granted in March 1981. The LaSalle, 
Units 1 and 2, Safety Evaluation Report (SER) (NUREG-0519) discusses 
the current exemption from 10 CFR Part 50, Appendix J, Option A, 
Sections III.C.2(a) and III.C.3, which is based on the conclusions 
that: (1) The MSIV leak testing methods for the LaSalle Station were 
acceptable alternatives to the cited requirements of Appendix J; and 
(2) the measured MSIV leakage rates could be excluded from the 
evaluation of the Type B and C tests. These conclusions and their bases 
are presented in Section 6.2.6.1 of the LaSalle SER.
    Specifically, the LaSalle SER described that in the event of a 
loss-of-coolant-accident (LOCA), the LaSalle MSIV leakage control 
system (LCS) would maintain a negative pressure between the inboard and 
outboard MSIVs and that the effluent from the LCS will be discharged 
into the standby gas treatment system (SGTS) in the reactor building 
before being released through a stack to the environment. In evaluating 
the licensee's requested exemption in the LaSalle SER, the staff based 
its decision to grant the exemption on the results of its independent 
radiological analysis assuming a TS leak rate limit of 11.5 standard 
cubic feet per hour (scfh). This TS limit and the subject exemption 
were subsequently modified in Supplement No. 6 to the LaSalle SER 
(issued in November 1983) to raise the TS allowable MSIV leakage rate 
for each of the four main steamlines to 25 scfh. The subject exemption, 
its description, and conditions have remained in force from that time 
to the present.
    The staff concluded in the LaSalle SER that the LaSalle Station 
testing procedure, in which two MSIVs on one steamline are tested 
simultaneously using a reduced test pressure of 20.2 pounds per square 
inch gage (psig) applied between the inboard and outboard MSIVs, was 
also acceptable. The use of this LaSalle MSIV test procedure was 
thereby granted as an exemption from certain of the testing 
requirements of Appendix J, Option A, to 10 CFR Part 50.
    In summary, the staff concluded that the current exemption granted 
in March 1981, as modified in November 1983, was acceptable based on: 
(1) The method of MSIV testing; (2) a radiological analysis that 
assumed a 25 scfh MSIV leak rate for each of the four main steamlines 
and whose radiological consequences for all primary containment leakage 
were within the radiation exposure guidelines of 10 CFR Part 100 and 
met the requirements of 10 CFR Part 50, Appendix A, General Design 
Crierion (GDC) 19; and (3) the licensee's commitment to periodically 
test the MSIVs to ensure that the measured MSIV leakage did not exceed 
the TS allowable MSIV leakage rates.
    The deletion of the MSIV LCS and use of an alternate leakage 
treatment (ALT) pathway (i.e., the main steamlines, the steam 
drainlines and the main condenser) as proposed in the licensee's letter 
dated August 28, 1995, as well as the licensee's proposal to raise the 
TS allowable MSIV leak rates, affects the description of one part of 
the subject exemption; i.e., that part which allows the exclusion of 
the measured leakage from the evaluation of the combined local leak 
rate test results. Accordingly, the licensee requested in its letter 
dated August 28, 1995, as supplemented in its letter dated March 4, 
1996, a modification to part of the subject exemption from the 
Commission's regulations in Appendix J. The proposed modification to 
the subject exemption is from the requirements of 10 CFR Part 50, 
Appendix J, Option B, Section III.B. which would allow the licensee to 
(1) continue using a reduced test pressure for the leakage testing of 
the MSIVs, and (2) continue to exclude the measured MSIV leakage from 
the combined local leak rate test results.
    The licensee also submitted in its letter dated August 28, 1995, a 
request for license amendments for the LaSalle Station in conjunction 
with the proposed modification of the existing exemption. The proposed 
license amendment would revise the LaSalle TSs to reflect the deletion 
of the MSIV LCS, utilize an ALT pathway and raise the TS allowable MSIV 
leakage. This proposal is based on the Boiling Water Reactor Owners 
Group (BWROG) method summarized in General Electric Report NEDC-31858P, 
Revision 2, ``BWROG Report for Increasing MSIV Leakage Rate Limits and 
Elimination of Leakage Control System,'' dated September 1993. When the 
license amendments are granted, part of the original exemption from the 
Appendix J leakage test requirements will not be applicable because the 
description and conditions of the original exemption will be 
significantly altered.
    An important element in the evaluation of the licensee's request to 
delete the MSIV LCS is whether the components of the proposed ALT 
pathway for MSIV leakage remain functional under design basis accident 
(DBA) conditions. In this regard, the staff reviewed the capability of 
the ALT pathway to withstand the seismic loads resulting from a safe 
shutdown earthquake (SSE) and remain functional. The staff's review of 
this aspect found that there was sufficient margin in all ALT 
components against gross failure under SSE conditions. Further, the 
staff found that the two redundant paths leading from the MSIVs to the 
main condenser provided an acceptable level of reliability for the 
proposed ALT pathway. Finally, the staff found that motor operated 
valves which define the boundaries of the ALT pathway either have: (1) 
reliable power sources; (2) will remain in their required open or 
closed position; or (3) will be administratively controlled. On this 
basis, the staff found that the proposed ALT pathway would remain 
functional under DBA conditions.
    The staff performed an independent assessment of the radiological 
consequences of the licensee's proposal to delete the present LCS and 
establish an ALT pathway to control and process the leakage past the 
MSIVs as well as the licensee's proposal to increase the TS allowable 
MSIV leakage rate. This radiation dose assessment evaluated the effect 
of the proposed hardware modifications and TS revisions separately and 
then combined these doses with those resulting from all other leakages 
from the LaSalle primary containment. The staff found in its 
radiological assessment of the proposed modification of the existing 
exemption that the potential offsite and control room doses to 
personnel remain within the applicable criteria of 10 CFR Part 50, 
Appendix A, GDC-19 and 10 CFR Part 100 and is consistent with the 
guidance in Standard Review Plan (SRP) Section 6.4.
    The proposed hardware and TS changes associated with deletion of 
the MSIV LCS do not affect the bases for part of the current exemption. 
The modification and implementation of the TS change requests will not 
alter the procedure for MSIV testing (i.e., the test may be performed 
at a minimum pressure of 20.2 psig applied between the inboard and 
outboard MSIVs). Furthermore, when Option B was added to Appendix J in 
September 1995 (60 FR 49495 (1995)), this version stated in Section 
V.B.1 that specific exemptions to Option A that have been formally 
approved by the NRC, are still applicable. On this basis, the staff 
finds that the portion of the existing exemption (i.e., the application 
of test pressure to its MSIVs) remains in force and no further 
consideration is required for this portion of the subject exemption 
request.
    As part of its evaluation of the TS change to delete the MSIV LCS, 
the NRC staff concluded that there is reasonable assurance that: (1) 
the current MSIV leak testing method (i.e., a minimum

[[Page 16272]]

test pressure of 20.2 psig applied between the inboard and outboard 
MSIVs) is an acceptable method for testing MSIV leakage; (2) the 
proposed MSIV leakage ALT pathway will withstand the seismic loads from 
an SSE and remain functional; and (3) the calculated radiation doses 
assuming an MSIV leakage rate limit of 100 scfh per main steamline, not 
to exceed 400 scfh for all four main steamlines, are within the 
radiation exposure guidelines in 10 CFR Part 100, meet the requirements 
of GDC-19 of Appendix A to 10 CFR Part 50 and are consistent with SRP 
Section 6.4. On this basis, the staff finds it acceptable to continue 
to exempt LaSalle, Units 1 and 2, from the 10 CFR Part 50, Appendix J, 
Option B, requirements to include the measured MSIV leakage rate from 
the combined local rate tests since the radiological consequences of 
the MSIV leakage are acceptable and continue to meet the underlying 
intent of the rule. Therefore, the staff finds that the requested 
modification to the existing exemption in the licensee's submittal 
dated August 28, 1995, as supplemented on March 4, 1996, may be 
granted.

III

    Pursuant to 10 CFR 50.12, the Commission may, upon application by 
any interested person or upon its own initiative, grant exemptions from 
the requirements of 10 CFR Part 50 when: (1) the exemptions are 
authorized by law, will not present an undue risk to public health and 
safety, and are consistent with the common defense and security; and 
(2) when special circumstances are present. Special circumstances are 
present whenever, according to 10 CFR 50.12(a)(2)(ii), ``Application of 
the regulation in the particular circumstances would not serve the 
underlying purpose of the rule or is not necessary to achieve the 
underlying purpose of the rule * * * .''
    The underlying purpose of the rule is to assure leakage through the 
primary reactor containment, and systems and components penetrating 
primary containment do not exceed allowable leakage rate values and 
that periodic surveillance is performed so that proper maintenance and 
repair are made. The staff analysis has demonstrated that an adequate 
margin can be maintained even if leakage past the MSIVs through the ALT 
pathway occurs at the TS allowable MSIV leakage rates of 100 scfh for 
each main steamline, not to exceed a total of 400 scfh for all four 
main steamlines.

IV

    Accordingly, the Commission has determined that, pursuant to 
Section 50.12 of 10 CFR Part 50, an exemption is authorized by law and 
will not present an undue risk to public health and safety, and that 
there are special circumstances present, as specified in 10 CFR 
50.12(a)(2). An exemption is hereby granted from the requirements of 
Sections III.B, of Appendix J, Option B, to 10 CFR Part 50 regarding 
testing the MSIVs at accident pressure and including MSIV leakage rates 
in the sum of the Type B and C leakage rates. The exemption allows: (1) 
leakage testing of the MSIVs using a minimum test pressure of 20.2 psig 
applied between MSIVs and a TS leakage rate limit of 100 scfh per main 
steamline past the MSIVs, not to exceed 400 scfh for all four main 
steamlines; and (2) exclusion of the measured MSIV leakage rate from 
the evaluation of the combined local leak rate tests.
    Pursuant to 10 CFR 51.32, the Commission has determined that the 
granting of this exemption will have no significant impact on the 
quality of the human environment (61 FR 14837).
    This exemption is effective upon issuance and will be implemented 
prior to startup of LaSalle, Unit 1, from its present refueling outage 
and implemented for LaSalle, Unit 2, prior to startup from its 
refueling outage scheduled to start in September 1996.

    For the Nuclear Regulatory Commission.

    Dated at Rockville, Maryland, this 5th day of April 1996.
Jack W. Roe,
Director, Division of Reactor Projects--III/IV, Office of Nuclear 
Reactor Regulation.
[FR Doc. 96-9145 Filed 4-11-96; 8:45 am]
BILLING CODE 7590-01-P