ML18094B285
| ML18094B285 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 01/25/1990 |
| From: | Labruna S Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-89-003, IEB-89-3, NLR-N90017, NUDOCS 9002130052 | |
| Download: ML18094B285 (6) | |
Text
I Public Service Electric and Gas Company Stanley LaBruna Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 080~8 609-339-4800 Vice President - Nuclear Operations JAN 2 5 1990 NLR-N90017 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:
RESPONSE TO NRC BULLETIN NO. 89-03 POTENTIAL LOSS OF REQUIRED SHUTDOWN MARGIN DURING REFUELING OPERATIONS SALEM UNITS NOS. 1 AND 2 FACILITY OPERATING LICENSE NOS. DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 Public Service Electric and Gas Company (PSE&G) has received the subject NRC Bulletin regarding potential loss of shutdown margin during refueling operations.
PSE&G has reviewed the bulletin and the information requested is provided in the enclosure to this letter.
Should you have any questions regarding this transmittal, please feel free to contact us.
Enclosure 1,:;J()(j 12~:.
o~::iooo272 F'DC Sincerely,
Document Control Desk NLR-,N90017 c
Mr. J. c. Stone Licensing Project Manager Mr. T. Johnson Senior Resident Inspector 2
Mr. w. T. Russell, Administrator Region I Mr. Kent Tosch, Chief New Jersey Department of Environmental Protection Division of Environmental Quality Bureau.of Nuclear Engineering CN 415 Trenton, NJ 08625 JAN 2 5 1990
ENCLOSURE RESPONSE TO NRC BULLETIN 89-03 SALEM UNITS NOS. 1 AND 2 FACILITY OPERATING LICENSE NOS. DPR-70 AND DPR-75 DOCKET NOS. 50-272 AND 50-311 The purpose of this bulletin was to request that the Licensee review it's refueling procedures to identify any possible decreases in Shutdown Margin (SDM).
The written response requested by Bulletin 89-03 is presented below.
NRC CONCERN
- 1.
Assure that any intermediate fuel assembly configuration (including control rods) intended to be used during refueling is identified and evaluated to maintain sufficient refueling boron concentration to result in a minimum shutdown margin of approximately 5%.
RESPONSE
PSE&G performed analysis in October 1988 to investigate the potential for loss of Shutdown Margin or inadvertent criticality during refueling operations.
The study is documented in Nuclear Fuels Group Calculation File DOl.6-498.
The analysis considered several cases which would be expected to bound all possible combinations conservatively with respect to K The calculation results and input requested fromet~e fuel vendor were used to develop guidelines.
The guidelines were incorporated into the refueling package and into training of refueling personnel and refueling SROs.
Since the issuance of NRC.Bulletin 89-03, the fuel vendor has issued generic guidelines addressing this topic.
The vendor guidelines have been reviewed for any improvements or additions to the previous direction.
The results of that review conclude that our existing guidelines are comparable and in some cases more limiting than the recently provided vendor guidelines.
The following are PSE&G's guidelines and the basis for each:
- a.
All burnable absorbers and RCCAs must be inserted in designated fuel assemblies as per the core loading pattern design prior to moving fuel into the reactor cavity area.
NLR-N90017 This guideline prevents completely loading the core with fuel, with no burnable poison or control rods.
- b.
Source bearing assemblies shall be inserted adjacent to
_the baffle before any other assemblies are loaded.
When relocated from the temporary to the final location, there shall be no water hqles between the detector and the source bearing assemblies.
This situation occurs early in core loading when leakage is high due to the small number assemblies loaded.
Thus this is not a limiting case and no specific calculations were performed.
- c.
If it is necessary to temporarily place assemblies aside to "box in" the desired location, prior to loading the assembly in the desired location, the temporary location must have either water or baffle adjacent to all four faces.
It must not be adjacent to the loaded core array or any other temporarily located assemblies.
If it is necessary to use fresh fuel assemblies to make the "box", the fresh fuel assemblies used must have 20 or more standard fresh burnable absorber rodlets or an RCCA inserted _in each fresh assembly not in its final core location.
This guideline limits the amount of reactivity increase associated with the. 11boxing in" of holes for the purpose of guiding bowed fuel assemblies in place during core loading.
- d.
With the exceptions noted in b and c above, assemblies must be placed only in their final location as designated by the core loading pattern design.
Any other exceptions to this requirement must be evaluated on a case by case basis.
This guideline prevents possible large reactivity increases that can occur due to incorrectly loading assemblies into positions other than those designated by.the core loading pattern.
- e.
The-source range counts (ICRR) must be monitored at all times for unexpected changes to preclude inadvertent criticality.
Daily boron concentration analysis of the refueling water will be performed to prevent possible dilution.
This guideline is to preclude an inadvertent criticality by monitoring source range count rates.
This does not ensure a refueling K
<.95.
Errors in the loading configurations could c~O:~e possible higher K
in core regions that are not detected at the d~t~ctor. This and the other guidelines are required to maintain Keff at appropriate values.
- f.
Boron concentration must be maintained ~300 ppm above the calculated boron concentration for K
=.95 for the final core configuration or greater @!£n 2,000 ppm, whichever is more restrictive.
This guideline includes the 1,000 ppm uncertainty allowance required by Technical Specifications and ari adequate allowance for variation in K ff under the above the guidelines during core loading. e This guideline provides K ff margin to accommodate K ff changes due to using fresff ruel assemblies to box ine locations for insertion of bowed assemblies.
One side and one end of the box consists of assemblies loaded into their final core location.
The other side and end (four assemblies) may be fresh fuel assemblies.
This is the side facing the open water.
NRC CONCERN
- 2.
Assure that.fuel loading procedures only allow_~hose intermediate.fuel assembly configurations that do not violate the allowable shutdown margin and that these procedures are strictly adhered to.
RESPONSE
PSE&G incorporated the above guidelines into the refµeling SRO duty supplement of the "Unanticipated Water Level Decrease Procedure", III-11, Rev. 2.
The refueling SRO duty supplement outlines the duties of the refueling SRO with respect to loss of refueling water level, normal refueling process and guidelines on temporary or intermediate configuration control.
The refueling SRO duty supplement is included in all copies of the refueling procedure package assembled for each refueling outage.
A copy of the refueling procedure package. is maintained in the control room and on the refueling floor, as well as other work locations.
The refueling SRO is charged with ensuring that the duties and limitations listed in the refueling SRO duty supplement are observed.
In addition, vendor refueling personnel are responsible to work to these guidelines.
NRC CONCERN
- 3.
Assure that the *Staff responsible for refueling operations is trained in the procedures recommended in Item 2 above and understand the potential consequences of violating these procedures.
This training should include the fundamental aspects of criticality control. with enriched fuel assemblies.
RESPONSE
PSE&G personnel conduct training with all vendor refueling personnel and PSE&G refueling SROs on procedure III-11.
The training is conducted as follows:
- a.
Prior to each refueling outage start of core fuel handling operations, all refueling personnel and refueling SROs shall be trained on the most current revision of procedure III-11.
- b.
In addition, any additional or replacement personnel
~ill be trained prior to their participation iri core fuel handling activities.
It is recognized that the above guidelines apply to the full core offload/reload process which is the present process utilized at Salem Units Nos. 1 and 2.
Prior to a fuel shuffle process, an online calculation capability would be required.
PSE&G has no plans to perform a fuel shuffle at Salem in the near future.
Should a fuel shuffle be planned at a later date, the appropriate calculations will be performed prior to any movement of fuel.