ML20212P464
| ML20212P464 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 08/26/1986 |
| From: | Kingsley O MISSISSIPPI POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML20212P458 | List: |
| References | |
| TAC-60587, TAC-60588, TAC-60589, TAC-60590, TAC-60591, TAC-60592, TAC-61782, NUDOCS 8609030145 | |
| Download: ML20212P464 (5) | |
Text
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BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION LICENSE N0. NPF-29 DOCKET N0. 50-416 IN THE MATTER OF MISSISSIPPI POWER & LIGHT COMPANY and MIDDLE SOUTH ENERGY, INC.
and SOUTH MISSISSIPPI ELECTRIC POWER ASSOCIATION AFFIRMATION I, 0. D.- Kingsley, Jr., being duly sworn, stated that I am Vice President, Nuclear Operations of Mississippi Power & Light Company; that on behalf of Mississippi Power & Light Company, Middle South Energy, Inc., and South Mississippi Electric Power Association I am authorized by Mississippi Power & Light Company to sign and file with the Nuclear Regulatory Commission, this application for amendment of the Operating License of the Grand Gulf Nuclear Station; that I signed this application as Vice President, Nuclear Operations of Mississippi Power & Light Company; and that the statements made and the matters set forth therein are true and correct to t best of my knowledge, information and belief.
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STATE OF MISSISSIPPI COUNTY OF HINDS SUBSCRIBED AND SWORN T0 before me, a Notary Public, in and for the County and State above named, this f4 f day of Ava ad
, 1986.
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$[ 0$o $ $IO (Npt'ary'Public My commission expires:
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Item 1 NPE-85/13 (Additional Submittal)
SUBJECT:
Technical Specification Surveillance Requirement 4.1.3.1.4.a; page 3/4 1-5.
DISCUSSION: Mississippi Power and Light (MP&L) Company proposed changes to Technical Specification 3/4.1.3.1 and to Facility Operating License NPF-29 in a letter dated January 29, 1986. Item 5 of that letter requested changes to allow implementation of a design change to add diverse and redundant Scram Discharge Volume (SDV) level instrumentation and redundant vent and drain valves. An additional submittal was made on April 14, 1986 to propose new action requirements and to withdraw new License Condition 2.C.(41) proposed in the January 29, 1986 submittal.
This license condition was proposed to be replaced with deletion of the 50% rod density scram test in Surveillance Requirement 4.1.3.1.4.a. The present submittal is being made after discussions with NRR staff concerning deletion of the 50% rod density scram test. The proposed changes to the previous submittal made on April 14, 1986 include retaining the 50% rod density scram test and adding a "*" footnote. The footnote will provide an exception to the provisions of Specification 4.0.4 provided the surveillarce is performed at least once per 18 months.
JUSTIFICATION: Redundant SDV vent and drain valves are being added in series and outboard of the present vent and drain valves. Present Surveillance Requirement 4.1.3.1.4.a requires that the SDV vent and drain valves be demonstrated operable by performing a scram test from a normal control rod configuration of less than or equal to 50% rod density at least once per 18 months. This surveillance test requires the SDV vent and drain valves to close within 30 seconds of receipt of the scram signal and to reopen when the scram signal is reset. In order to perform this surveillance test, Operational Condition 1 or 2 must be entered so that control rods can be withdrawn. The proposed exception to the provisions of Specification 4.0.4 will allow entry into Operational Conditions'l or 2 in order to allow plant operation and performance of the required testing.
The proposed "*" footnote will also require that Surveillance Requirement 4.1.3.1.4.a be performed at least once per 18 months. The intent of this provision is to allow the plant to enter Operational Conditions 1 or 2 without having performed Surveillance Requirement 4.1.3.1.4.a and to continue operation as long as the surveillance is performed within an 18 month interval and at least once per 18 months thereafter. MP&L believes that satisfactory performance of the SDV vent and drain valves can be demonstrated by testing without imposing unnecessary plant scrams. By allowing an 18 month frequency for the scram test from 50% rod density, this test can be J16ATTC86081501 - 1
performed during planned shutdowns without imposing an undue hardship on the plant. MP&L views the 50% rod density test as only one of several tests that demonstrate operability of the SDV. Other tests that are performed include quarterly ASME Section XI valve timing and post maintenance or construction functional tests. Another factor that decreases the significance of the closure function of the SDV vent and drain valves at Grand Gulf is that the vent and drain lines terminate in the suppression pool located inside primary containment.
The new SDV vent and drain valves are manufactured by ITT Hammel Dahl. These valves are globe valves with a 2500 lb.
class rating. These valves are spring to close, air to open, with an integral side mounted handwheel. The new vent valve is a one inch model 522FRR62HAZ9 and the new drain valve is a two inch model 522JRR62HAZ9. These new valves are being installed with an orientation such that flow from the SDV will tend to close the valves. It should be noted that these new valves being installed at Grand Gulf are the same type and in some cases the same model number as valves installed and functioning properly in the same service at other operating BWRs.
The SDV instrument volumes are located in the containment at elevation 135'. The work area is not overly congested with equipment and construction access to the vent and drain lines is-adequate. Personnel working on the modification will include but not be limited to approximately four construction workers, a Quality Assurance inspector, a field engineer, and a construction superintendent. The valves are prepared for installation in the fabrication-shop by welding pipe to each open end of the valve body. A section of pipe is removed from each SDV vent and drain line and the new valve is installed by socket welding at the upstream connection. After installation, the new valves and piping are pressure tested to ensure weld integrity and then the downstream connection is made to the existing vent and drain line using socket welds. The drain valve and line is pressure tested to 1562 psig and the vent valve and line is pressured tested to 1250 psig. During the installation process, QA hold points provide for inspections to ensure that work is satisfactory. Field engineer walk downs
- are also performed to ensure proper installation of valves including air and electrical connections.
Post installation functional testing of the new SDV vent and drain valves will be performed to demonstrate proper stroke i times for the Inservice Inspection program and to set and f verify proper opening and closing sequencing. The new outboard SDV vent and drain valves will be set to close nominally five seconds after and open nominally five seconds before the presently installed inboard vent and drain valves to address hydrodynamic concerns.
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.Special testing provisions to ensure proper vent and drain flow and to demonstrate system level functioning will be performed after-the installation of the new valves.- In order-to demonstrate proper flows, a test will be conducted prior to the~
modification by filling the SDV instrument volume with water
.and determining' a drain flow rate after the vent.and drain valves are given'an.open signal. The same flow test will be performed after installation of the new valves to ensure that flow values are comparable with the. previous test. In addition to a flow test, a system level SDV test will be performed after the modification is complete. This test will involve introducing a scram during shutdown to verify all system >
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components function as required. While the scram signal is U present all SDV vent and drain valve closure times will be
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measured to ensure compliance with the 30 second closure
', criteria. After reset of the scram signal, the SDV vent and -
! drain valves will be verified to open and the SDV will be
! checked to ensure proper drainage.
-After the first refueling outage, maintenance on components of the SDV may be required that could affect flow rates and/or SDV
_ operability.. MP&L commits to evaluate each maintenance i activity affecting SDV operability and to perform retests of C parts or of the entire SDV, as necessary, to ensure operability -
of affected components. These retests may involve but are not limited to the post installation' testing described above.for the new SDV vent-and drain valves.
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- SIGNIFICANT HAZARDS CONSIDERATION:
t The proposed change does not involve a significant hazards 4 consideration because operation of Grand Gulf Unit 1 in i- accordance with this change would not:
- (1) involve a significant increase in the probability'or ,
- - consequences of an accident previously evaluated.
This change is necessary to allow entry into a
! required operational condition to perform the test.
l The 18' month time frame for performing the 50% rod density test is justified because other testing of the SDV vent and drain valves demorstrate proper functioning. ASME Section XI quarterly tests '
demonstrate (without'a scram) that the SDV vent and drain ' valves function properly. Also post maintenance and post construction testing assures proper
! functioning of the valves. The 18 month 50% rod density test will add further assurance that the SDV-is functioning properly in its operating configuration. Therefore, this change does not
- increase the probability or consequences of an accident previously evaluated.
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(2) create the possibility of a new or different kind of accident from any previously analyzed. Testing of the SDV vent and drain valves is performed quarterly by ASME Sec' tion XI requirements. This testing along with post maintenance and post construction testing demonstrate operability prior to entering Operational Conditions 1 or 2 and justifies continued operation without performing the 50% rod density scram test until due. The 50% rod density test, when performed at least once per 18 months, provides an additional check on the functioning of the SDV in its normal operating configuration. This change in surveillance requirements does not create the possibility.of a new or different kind of accident.
(3) involve a significant reduction in a margin of safety. Since testing measures other than the 50%
rod density scram test demonstrate operability of the SDV vent and drain valves, this proposed change will not reduce the margin of safety.
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