[Federal Register Volume 60, Number 32 (Thursday, February 16, 1995)]
[Notices]
[Pages 9059-9060]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-3879]
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NUCLEAR REGULATORY COMMISSION
[Docket Nos. 50-237, 50-249 50-254, 50-265]
Commonwealth Edison Co., Facility Operating License
Exemption
In the Matter of Commonwealth Edison Co. (Dresden Nuclear Power
Station, Units 2 and 3; Quad Cities Nuclear Power Station, Units 1
and 2).
I
Commonwealth Edison Company (ComEd, the licensee) is the holder of
Facility Operating License Nos. DRP-19 and DRP-25, which authorize
operation of Dresden Nuclear Power Station, Units 2 and 3, at a steady
state power level not in excess of 2527 megawatts thermal; and Facility
Operating license Nos. DRP-29 and DRP-30, which authorize operation of
Quad Cities Nuclear Power Stations, Units 1 and 2, at a steady state
power level not in excess of 2511 megawatts thermal. Dresden Station is
comprised of two boiling water reactors at the licensee's site located
in Grundy County, Illinois. Quad Cities Station is comprised of two
boiling water reactors at the licensee's site located in Rock Island
County, Illinois. These licenses provide, among other things, that
Dresden and Quad Cities are subject to all rules, regulations, and
Orders of the U.S. Nuclear Regulatory Commission (the Commission) now
or hereafter in effect.
II
By letter dated October 4, 1994, the licensee requested a revision
to an exemption from certain Type B (local leak rate) testing
requirements of appendix J to 10 CFR part 50, for two-ply containment
penetration expansion bellows at four reactor units. The request was
made because the licensee has developed a set of alternative approaches
which can be applied to ensure the intent of requiring a Type A test,
as part of the original exemption, is met.
On February 6, 1992, the NRC issued an Exemption from certain Type
B testing requirements of Appendix J. This exemption stated upon
completion of the two-ply bellows testing program, a Type A integrated
leak rate test (ILRT) will be performed to verify primary containment
integrity. The testing program was intended to assure that at least one
ply of a two-ply bellows is intact and that overall containment leakage
is within its allowable limit as shown by Type A testing. The Type A
test was the only test available that could properly quantify the
bellows' leakages, albeit not individually. The Exemption also stated
that if a method is developed which ensures a valid Type B test on one
or more bellows assemblies, those bellows will also be excluded from
the Exemption and will be required to be tested in accordance with the
normal Type B test program.
III
The original Exemption allowed ComEd to apply special testing
techniques in lieu of performing a test which meets Type B requirements
for these bellows which, at that time, were unable to be tested in
strict conformance to the appendix J criteria. The special testing
techniques included a sequence of air and helium based local leak rate
tests (LLRT) for each affected penetration and performance of a Type A
leak rate test upon completion of the bellows testing during each
refuel outage.
Commonwealth Edison Company now believes that the requirement to
perform a Type A test every outage is not necessary to ensure that the
bellows assemblies are adequately tested and leakage from any leaking
bellows assembly is adequately quantified. Through testing of two-ply
bellows at Dresden Station and Quad Cities Station, the licensee has
developed the following insights:
1. There is minimal probability for the occurrence of a large leak
in a two-ply bellows;
2. the special testing program is effective for identifying small
leaks in two-ply bellows;
3. the Type A test is ineffective for identifying small leaks in
two-ply bellows; and
4. more cost effective alternative methods have been developed for
quantifying leakage.
At the time of the original request for an exemption, a Type A test
was required every outage in accordance with the Technical
Specifications (TS) and appendix J criteria for determination of ILRT
test frequency. Based on appendix J and the TS, ComEd need not do a
Type A test every refuel outage if they have completed two consecutive
successful Type A tests. Quad Cities has completed two consecutive
successful Type A tests. However, as previously stated the original
exemption requires a Type A test every outage to support the two-ply
bellows leakage testing.
The licensee has discovered very small leaks using the special
testing techniques in some bellows and they have subsequently been
modified, removed from the list described in the original exemption and
are not on a Type B testing schedule.
The licensee has identified several methods for conducting a valid
Type B test on bellows since the original Exemption was issued. The
first method involves the addition of a bellows test enclosure equipped
with leaktight seals. The second involves installation of a rubber boot
inside the drywell to form a seal between the drywell atmosphere and
the bellows. The third is to weld a cover plate inside the drywell to
provide a seal between the process pipe and the drywell atmosphere. The
licensee also has the option to implement a complete replacement of the
existing two-ply bellows assemblies with a new testable two-ply
bellows.
The licensee has proposed the following revision to the approved
exemption for non-Type B testable bellows. This proposal eliminates the
need but keeps the option to perform a Type A test every refuel outage.
The licensee proposed to include the following alternatives to the
current requirement in place of the existing Section III.6 and .7 in
the original Exemption:
Upon completion of the two-ply bellows special testing program,
the following actions shall be taken to address any two-ply bellows
which have been identified as leaking through both plies:
(A) All bellows which leak through both plies shall be tested in
accordance with Type B requirements to ensure license limits are met
prior to return to service, or
(B) A Type A ILRT test shall be performed to verify primary
containment integrity. All two-ply bellows assemblies which
demonstrate leakage through both plies shall be replaced or
subjected to a valid Type B test to demonstrate license limits are
met prior to return to service from the subsequent refuel outage,
unless ComEd provides justification for continued operation greater
than one operating cycle.
The licensee states that the estimated cost of a Type A test, as
described in NUREG-1493, ``Performance-Based Containment Leak-Test
Program,'' Draft Revision 2, dated March 31, 1994, is $1.89 million.
Based on the number of historical leaking bellows found at Dresden and
Quad Cities during the refuel outages, the cost of the Type A test per
bellows ranges from $378k to $1.89M. The licensee also states that the
Type A tests performed every outage since approval of the current
exemption have never found a bellows leak which was undetected by the
special testing program. The techniques of the special
[[Page 9060]] test program have the ability to detect leaks smaller
than would be detected by the Type A test.
For a two-ply bellows that leaks through both plies, this revised
exemption allows: (1) A valid Type B test using one of various
developed alternatives to ensure compliance to license limits, or (2) a
Type A test as required in the original exemption and, before the
return to power in a subsequent refuel outage, replacement of the
bellows with a testable bellows assembly or a valid Type B test to
ensure license limits are met.
The staff finds that the underlying purpose of the regulation will
be met in that the proposed testing program will detect bellows
assemblies with significant flaws and result in replacement of flawed
assemblies within one operating cycle, or be tested with a Type B test
to ensure license limits are met during which period there is
reasonable assurance that the bellows assemblies will not suffer
excessive degradation. If the licensee should propose to wait longer
than one cycle to replace any bellows assembly, the staff must evaluate
and approve the request at that time.
IV
Accordingly, the Commission has determined that, pursuant to 10 CFR
50.12(a)(i) and (a)(2)(ii), that (1) the Exemption from appendix J is
authorized by law, will not present an undue risk to the public health
and safety, and is consistent with the common defense and security, and
(2) application of the regulation in this particular circumstance is
not necessary to achieve the underlying purpose of its rule.
The Commission concludes that the testing and replacement program
for the containment penetration bellows assemblies is an acceptable
alternative to the existing appendix J testing requirement.
Accordingly, the Commission hereby grants the Exemption from appendix
J.
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 (59 FR 64001).
This exemption is effective upon issuance.
Dated at Rockville, Maryland this 9th day of February 1995.
For the Nuclear Regulatory Commission.
Jack W. Roe,
Director, Division of Reactor Projects III/IV, Office of Nuclear
Reactor Regulation.
[FR Doc. 95-3879 Filed 2-15-95; 8:45 am]
BILLING CODE 7590-01-M
